<p id="isPasted">Plastic injection molding is a transformative process that turns raw polymer pellets into essential parts for industries worldwide. Among the numerous factors influencing mold design and production quality, <strong>Melt Flow Rate (MFR)</strong> stands out as a key characteristic that moldmakers must understand and optimize.</p><p><strong>Why Melt Flow Rate Matters</strong></p><p>MFR measures the ease with which a polymer flows under specific conditions of temperature and pressure. While it is often evaluated alongside Melt Flow Index (MFI), the MFR is particularly relevant in high-shear environments like injection molding. It provides insights into:</p><ul type="disc"><li><strong>Material Fluidity</strong>: High MFR polymers flow like water, enabling intricate part geometries. Low MFR polymers, resembling the viscosity of honey or concrete, demand greater force to fill the mold.</li><li><strong>Process Consistency</strong>: A stable MFR ensures uniformity between production batches, reducing defects and waste.</li><li><strong>Compatibility</strong>: Knowing the MFR helps match polymers to specific molding machines and processes.</li></ul><p>Understanding MFR allows moldmakers to anticipate flow behavior, ensuring precise gate sizing, optimal venting, and appropriate runner systems.</p><p><strong>MFR in Mold Design and Manufacturing</strong></p><p>When starting a mold project, evaluating MFR helps answer critical design questions, such as:</p><ol start="1" type="1"><li>How will the polymer flow through the mold?</li><li>Can the mold handle variations in flow due to additives or fillers?</li><li>What cycle time is achievable with the selected material?</li></ol><p>For example, polymers with high MFR are suited for thin-walled parts but may require tighter tolerances in vents and gates to prevent flash. In contrast, low MFR polymers are better for parts requiring high strength but may increase cycle times due to their slower flow.</p><p><strong>Shear and Viscosity: The Bigger Picture</strong></p><p>While MFR provides a baseline for understanding polymer behavior, moldmakers must also consider how shear and viscosity interact. Shear, the sliding of polymer layers against each other, directly affects the viscosity during the molding process.</p><ul type="disc"><li><strong>High Shear Rates</strong>: These typically lower polymer viscosity, making flow easier but increasing the risk of defects like gate blush or material degradation.</li><li><strong>Low Shear Rates</strong>: Maintain material integrity but may struggle to fill complex geometries, especially with low MFR polymers.</li></ul><p>Thus, MFR serves as a foundational metric, but it must be paired with shear and viscosity data for comprehensive mold design.</p><p><strong>From Pellet to Part: Optimizing the Process</strong></p><p>By integrating MFR data with mold flow simulations, moldmakers can predict and mitigate production challenges. These simulations help identify critical factors such as:</p><ul type="disc"><li><strong>Knit line locations</strong></li><li><strong>Optimal press size</strong></li><li><strong>Cycle efficiency</strong></li></ul><p>The goal is to harmonize all components of the process, from the injection screw to the cooling system, for maximum reliability and performance.</p><p><strong>A Competitive Edge with MFR Expertise</strong></p><p>MFR knowledge empowers moldmakers to deliver solutions tailored to specific materials and applications. For instance, understanding the limitations and potential of MFR helps prevent costly redesigns, ensures consistent part quality, and strengthens customer trust.</p><p><strong>Conclusion</strong><br>Melt Flow Rate isn’t just a technical metric; it’s a gateway to smarter, more efficient mold design. By leveraging MFR alongside other material properties, moldmakers can enhance part performance, reduce production errors, and stay competitive in a demanding market. For more details, please visit us at <a href="http://www.apsx.com" target="_blank" rel="noopener noreferrer">www.apsx.com</a>.&nbsp;</p>

Among the numerous factors influencing mold design and production quality, Melt Flow Rate (MFR) stands out as a key characteristic that mold makers must understand and optimize.

The Journey from Pellet to Part: Mastering Melt Flow Rate in Injection Molding

<p dir="ltr" id="isPasted">Plastic injection molding is the most common production process for simple plastic parts with thin walls. It is fast, cheap, and ideal for mass production. However, an injection molding machine is a complex piece of equipment, and the process is prone to a few specific problems that can lead to part defects.</p><p dir="ltr">Injection molding defects can significantly impact the quality and performance of manufactured products — or render them completely unusable and destined for the scrapheap. This can in turn lead to increased production costs, reduced efficiency, and compromised product reliability. For manufacturers, addressing these issues is key to maintaining quality standards and ensuring customer satisfaction.</p><p dir="ltr">Understanding plastic injection molding defects involves identifying their causes, diagnosing their presence, and implementing preventive measures. This article looks at some of the most common injection molding defects, examining why they occur and how to prevent them.</p><h2 dir="ltr">What Are Injection Molding Defects?</h2><p><span class="fr-img-caption fr-fic fr-dib" style="width: 832px;"><span class="fr-img-wrap"><img src="https://s3-us-west-1.amazonaws.com/wevolver-project-images/froala%2F1733143119052-yellow_black_plastic_parts.jpg" style="width: 100%px;" class="fr-fic fr-dib" alt="parts"><span class="fr-inner">Because they are made quickly and affordably, molded parts can exhibit defects</span></span></span></p><p dir="ltr">Injection molding defects are imperfections or anomalies that occur during the manufacturing process of molded products. These defects can manifest in various forms, such as surface blemishes, structural inconsistencies, or dimensional inaccuracies. They can undermine the functionality, aesthetics, and durability of the finished products, often leading to increased waste and production costs.[1]</p><p dir="ltr">Proactively identifying and mitigating defects can save resources, reduce operational costs, and lead to high-quality parts. By prioritizing defect management, manufacturers can enhance their competitiveness and foster sustainable production practices.</p><h2 dir="ltr">Common Types of Injection Molding Defects</h2><p dir="ltr">Injection molding is a highly efficient manufacturing process, but it is not without its challenges. Defects can arise at various stages of production, affecting the functionality, aesthetics, and overall quality of the final product. Below are some of the most frequent defects encountered in injection molding, along with their causes and implications:</p><h3 dir="ltr">Sink Marks</h3><p dir="ltr">These are shallow depressions or dimples that form on the surface of molded parts, often around thicker sections of material. Sink marks occur when the material inside the part cools and shrinks unevenly, pulling the surface inward. They are commonly caused by insufficient packing pressure, inadequate cooling time, or poor mold design features such as inconsistent ribs.[2]</p><h3 dir="ltr">Warping</h3><p dir="ltr">Warping is the unwanted bending or twisting of molded parts after ejection from the mold. It is primarily caused by uneven cooling rates across the part, leading to residual stresses that distort the shape. Warping can also result from improper material selection, as some polymers are more prone to shrinkage and deformation than others.</p><h3 dir="ltr">Short Shots</h3><p dir="ltr">A short shot happens when the molten material does not completely fill the mold cavity, resulting in incomplete or missing sections of the part. This defect is often caused by inadequate injection pressure or obstructions within the mold. It can also occur if the mold is poorly vented, preventing the material from flowing freely.</p><h3 dir="ltr">Flash</h3><p dir="ltr">Flash is an excess layer of material that seeps out of the mold cavity along the mold parting line or around ejector pins. This defect can occur if the mold is not clamped tightly enough or if the clamping force is uneven. Flash can also result from excessive injection pressure or worn mold components that allow material to escape.</p><h3 dir="ltr">Burn Marks</h3><p dir="ltr">Burn marks are darkened or charred areas on the surface of molded parts, typically caused by trapped air overheating during the injection process. These marks are usually found near sharp corners, flow path ends, or areas where air cannot escape the mold cavity. Factors contributing to burn marks include high injection speeds, insufficient venting, or improper gate design.</p><h3 dir="ltr">Flow Lines</h3><p dir="ltr">Flow lines are visible streaks or patterns on a molded part’s surface, caused by the cooling and solidification of material as it flows through the mold. These defects are often linked to inconsistent injection speeds, material temperature, or poor mold design. Although flow lines are typically cosmetic, they can indicate potential weaknesses in the part.</p><h3 dir="ltr">Delamination</h3><p dir="ltr">Delamination refers to the peeling or separation of surface layers on a molded part, resulting in a flaky or brittle texture. This defect is sometimes caused by contamination of the material, such as moisture or foreign particles. It can also occur if incompatible materials or additives are used together or if the material experiences excessive shear stress during molding.</p><h3 dir="ltr">Jetting</h3><p dir="ltr">Jetting appears as wavy, worm-like lines on the surface of molded parts, caused by irregular material flow of the molten plastic. This defect occurs when molten material is injected too quickly or at an improper angle, leading to turbulence rather than smooth filling. Jetting can also result from incorrect gate design or insufficient mold temperature. Proper flow rate and gate positioning can help mitigate this issue.</p><h3 dir="ltr">Voids</h3><p dir="ltr">Voids are small cavities or air pockets that form inside molded parts, often reducing their structural integrity. They typically occur due to uneven cooling, excessive material shrinkage, or trapped air during the molding process. Poorly designed runners or gates and insufficient holding pressure can exacerbate the issue. Adjusting cooling profiles and improving mold venting can help prevent voids.</p><h3 dir="ltr">Knit Lines</h3><p dir="ltr">Knit lines, also known as weld lines, are visible seams where two flow fronts of molten material meet but fail to fully fuse. This defect is often caused by insufficient material temperature or pressure, long flow paths, or improper gate placement. While sometimes purely cosmetic, knit lines can compromise strength. Enhancing material flow and optimizing mold design can reduce their occurrence.</p><p dir="ltr"><strong>Recommended reading: <a href="https://www.wevolver.com/article/the-pros-and-cons-of-3d-printing-low-run-injection-molds" target="_blank"><em>The pros and cons of 3D printing low-run injection molds</em></a></strong></p><h2 dir="ltr">Root Causes of Injection Molding Defects</h2><h3 dir="ltr">Material-Related Causes</h3><p><span class="fr-img-caption fr-fic fr-dib" style="width: 832px;"><span class="fr-img-wrap"><img src="https://s3-us-west-1.amazonaws.com/wevolver-project-images/froala%2F1733143131103-colorful_plastic_pellets.jpg" style="width: 100%px;" class="fr-fic fr-dib" alt="injection molding materials"><span class="fr-inner">Some injection molding materials are more defect-prone than others</span></span></span></p><p dir="ltr">The type and quality of plastic materials used in injection molding play a role in determining the success of the process. Factors such as moisture content, contamination, and material compatibility can directly influence the occurrence of defects.</p><ul><li dir="ltr"><p dir="ltr"><strong>Moisture Content</strong>: Excess moisture in raw molding materials can lead to defects like voids, bubbles, or delamination in the finished product. Certain plastics, such as polycarbonate and nylon, are hygroscopic and require proper drying before use to prevent moisture-related issues.</p></li><li dir="ltr"><p dir="ltr"><strong>Contamination</strong>: Foreign particles or impurities in the material can cause surface blemishes, inconsistent textures, or reduced structural integrity. For instance, contamination with incompatible polymers or dust can result in brittle or uneven parts.</p></li><li dir="ltr"><p dir="ltr"><strong>Material Selection</strong>: Some materials are simply more prone to certain defects than others. For example, polypropylene may exhibit sinking, fiber-filled plastics may warp, and moisture-filled nylon can sputter and create various defects.</p></li></ul><h3 dir="ltr">Process-Related Causes</h3><p dir="ltr">The parameters used during the injection molding process also greatly affect the quality and consistency of the final product. Variations in temperature, pressure, and injection speed can introduce defects if not carefully controlled.</p><ul><li dir="ltr"><p dir="ltr"><strong>Temperature</strong>: Inconsistent or incorrect material temperatures can lead to issues such as burn marks, short shots, or material degradation. For instance, excessive melt temperature can cause thermal degradation, resulting in discoloration or reduced material strength.</p></li><li dir="ltr"><p dir="ltr"><strong>Pressure</strong>: Insufficient or excessive injection pressure (back pressure and/or holding pressure) can lead to defects. Low pressure may cause short shots or incomplete filling of the mold cavity, while excessive pressure can lead to flash or damage to the mold.</p></li><li dir="ltr"><p dir="ltr"><strong>Injection Speed</strong>: The speed at which material is injected into the mold impacts the flow and cooling dynamics. High injection speeds may trap air within the mold, causing burn marks, while low speeds can lead to flow lines or incomplete filling.</p></li></ul><h3 dir="ltr">Design-Related Causes</h3><p dir="ltr">Product and mold design are important factors in the success of the injection molding process. Poor design choices can lead to a variety of defects, impacting both the structural integrity and aesthetic quality of the molded part.</p><ul><li dir="ltr"><p dir="ltr"><strong>Wall Thickness</strong>: Uneven or excessively thick walls can cause defects such as sink marks, warping, or voids. For example, parts with inconsistent wall thickness may cool unevenly, leading to residual stresses and dimensional inaccuracies.</p></li><li dir="ltr"><p dir="ltr"><strong>Rib Design</strong>: Improper rib placement or dimensions can result in defects like sink marks or weld lines. Ribs that are too thick relative to the surrounding walls can create localized shrinkage, causing surface imperfections and weakened structural areas.</p></li><li dir="ltr"><p dir="ltr"><strong>Gate Location</strong>: The placement of gates in the mold affects the flow of molten material. Poorly positioned gates can lead to defects such as flow lines, air traps, or incomplete filling. Researchers have argued that gate location is one of the most important considerations for minimizing wastage and energy costs and consequently increasing sustainability.[3]</p></li></ul><p dir="ltr"><strong>Recommended reading: <a href="https://www.wevolver.com/article/what-are-injection-mold-sprues-runners-and-gates" target="_blank"><em>What are injection mold sprues, runners, and gates?</em></a></strong></p><h2 dir="ltr">Identifying, Diagnosing, and Predicting Defects</h2><h3 dir="ltr"><span class="fr-img-caption fr-fic fr-dib" style="width: 832px;"><span class="fr-img-wrap"><img src="https://s3-us-west-1.amazonaws.com/wevolver-project-images/froala%2F1732650534151-mold-and-inserts-large-1920x1080-v2.jpg" style="width: 100%px;" class="fr-fic fr-dib" alt="moldflow"><span class="fr-inner">Flow simulation tools like Autodesk Moldflow can prevent defects (image credit:&nbsp;<a href="https://www.autodesk.com/ca-en/products/moldflow/" target="_blank" rel="noopener noreferrer">Autodesk</a>)</span></span></span>Visual Inspection</h3><p dir="ltr">Visual inspection is a fundamental step in identifying defects in molded parts. By systematically examining parts after production, manufacturers can detect and address quality issues early.</p><ul><li dir="ltr"><p dir="ltr"><strong>Examine Surface Quality</strong>: Look for visible imperfections such as sink marks, burn marks, or flash. These defects often indicate problems with material flow, temperature, or mold clamping.</p></li><li dir="ltr"><p dir="ltr"><strong>Check for Dimensional Accuracy</strong>: Measure critical dimensions to detect warping, short shots, or shrinkage. Variances in size can compromise the fit and functionality of the part.</p></li><li dir="ltr"><p dir="ltr"><strong>Inspect Weld and Flow Lines</strong>: Observe areas where material flows meet or change direction. Flow lines may appear as streaks or discolorations, while weld lines can signal weakened structural points.</p></li><li dir="ltr"><p dir="ltr"><strong>Assess Overall Consistency</strong>: Compare parts from the same production run to identify variations. Inconsistent quality across parts can highlight issues with process parameters or mold design.</p></li></ul><h3 dir="ltr">Advanced Diagnostic Tools</h3><p dir="ltr">Advanced diagnostic tools play a crucial role in identifying and analyzing defects in injection molding processes (or predicting them in advance). These technologies provide deeper insights into the root causes of defects, enabling manufacturers to make informed adjustments and improve quality.</p><div dir="ltr" align="left"><table><tbody><tr><td><p dir="ltr"><strong>Tool</strong></p></td><td><p dir="ltr"><strong>Description</strong></p></td><td><p dir="ltr"><strong>Benefits</strong></p></td><td><p dir="ltr"><strong>Limitations</strong></p></td></tr><tr><td><p dir="ltr"><strong>Thermal Imaging</strong></p></td><td><p dir="ltr">Detects temperature variations across the molded part and within the mold during the injection process. Identifies areas prone to uneven cooling (e.g., warping, sink marks).</p></td><td><p dir="ltr">Non-invasive&nbsp;</p><p dir="ltr">Real-time analysis&nbsp;</p><p dir="ltr">Easy identification of thermal inconsistencies</p></td><td><p dir="ltr">Limited detection of internal defects&nbsp;</p><p dir="ltr">Cannot identify material-related issues</p></td></tr><tr><td><p dir="ltr"><strong>X-ray Inspection</strong></p></td><td><p dir="ltr">Examines the internal structure of molded parts, detecting voids, inclusions, or incomplete filling not visible externally.</p></td><td><p dir="ltr">High precision&nbsp;</p><p dir="ltr">Assesses material integrity</p></td><td><p dir="ltr">High cost&nbsp;</p><p dir="ltr">Requires specialized equipment and expertise</p></td></tr><tr><td><p dir="ltr"><strong>Flow Simulation Software</strong></p></td><td><p dir="ltr">Models the flow of molten material within the mold, predicting issues like air traps, weld lines, or improper filling. Optimizes mold design and process parameters.</p></td><td><p dir="ltr">Prevents defects proactively&nbsp;</p><p dir="ltr">Reduces costly trial-and-error processes</p></td><td><p dir="ltr">Requires accurate input data&nbsp;</p><p dir="ltr">Demands significant computational resources</p></td></tr></tbody></table></div><h1 dir="ltr">Material Quality Assurance Checklist</h1><p dir="ltr">Prevention of injection molding defects largely comes down to skilled part design and machine operation. However, choosing the right materials and ensuring their proper handling can also help to prevent injection molding defects. Material properties such as viscosity, thermal stability, and moisture absorption can significantly impact the quality of molded parts.</p><p dir="ltr">Some best practices when obtaining and handling materials for injection molding include:</p><ul style="list-style-type: circle;"><li dir="ltr"><p dir="ltr">Verify material certification and supplier quality standards.</p></li><li dir="ltr"><p dir="ltr">Inspect raw materials for signs of contamination, discoloration, or damage.</p></li><li dir="ltr"><p dir="ltr">Test moisture content before processing and ensure it meets the manufacturer’s specifications.</p></li><li dir="ltr"><p dir="ltr">Conduct small-scale trial runs to confirm material performance under intended processing conditions. Adhering to these practices helps ensure material integrity and minimizes the likelihood of defects during injection molding.</p></li></ul><h1 dir="ltr">Conclusion</h1><p dir="ltr">Effectively managing injection molding defects requires an understanding of their causes and the proactive implementation of preventive measures. Manufacturers can enhance product quality by selecting the appropriate materials, optimizing injection molding processes, and designing molds thoughtfully. These efforts not only minimize production costs but also ensure the reliability and consistency of molded parts.</p><p dir="ltr"><strong>Recommended reading: <a href="https://www.wevolver.com/article/3d-printing-vs-injection-molding" target="_blank"><em>3D printing vs injection molding: process, materials, applications</em></a></strong></p><h1 dir="ltr">Frequently Asked Questions (FAQs)</h1><p dir="ltr"><strong>Q: What are the most common injection molding defects?</strong></p><p dir="ltr">A: Common defects in injection molded parts include sink marks, warping, short shots, flash, burn marks, and flow lines. Each arises from different factors such as material properties, processing conditions, or mold design.</p><p dir="ltr"><strong>Q: How does material selection impact defect prevention?</strong></p><p dir="ltr">A: Material properties such as moisture absorption, thermal stability, and viscosity significantly affect defect risks. Selecting materials suited to the application and process conditions is essential for defect prevention.</p><p dir="ltr"><strong>Q: What role does process monitoring play in reducing defects?</strong></p><p dir="ltr">A: Process monitoring helps detect anomalies in real time, ensuring consistent quality. Tracking parameters such as temperature, pressure, and cooling rates allows for early adjustments to avoid defects.</p><p dir="ltr"><strong>Q: Can flow simulation software help prevent defects?</strong></p><p dir="ltr">A: Yes, flow simulation software models the material's behavior within the mold, predicting potential issues like air traps, weld lines, or incomplete filling. This helps optimize mold design and processing parameters.&nbsp;</p><p dir="ltr"><strong>Q: Why is mold design critical to defect prevention?</strong></p><p dir="ltr">A: Mold design determines how material flows, cools, and solidifies. Features like gate placement, wall thickness, and rib design directly impact defect risks and product quality.</p><h1 dir="ltr">References</h1><p dir="ltr">[1] Chen YM, Liu JJ. <a href="https://www.sciencedirect.com/science/article/pii/S0736584599000058" target="_blank">Cost-effective design for injection molding</a>. Robotics and computer-integrated manufacturing. 1999 Feb 1;15(1):1-21.</p><p dir="ltr">[2] Gruber DP, Berger G, Pacher G, Friesenbichler W.<a href="https://www.sciencedirect.com/science/article/abs/pii/S0142941811000717" target="_blank">&nbsp;Novel approach to the measurement of the visual perceptibility of sink marks on injection molding parts</a>. Polymer testing. 2011 Sep 1;30(6):651-6.</p><p dir="ltr">[2] Huszar M, Belblidia F, Davies HM, Arnold C, Bould D, Sienz .<a href="https://www.sciencedirect.com/science/article/pii/S2214993715000093" target="_blank">&nbsp;Sustainable injection moulding: The impact of materials selection and gate location on part warpage and injection pressure</a>. Sustainable Materials and Technologies. 2015 Sep 1;5:1-8.</p>

Injection molding problems like sink marks and flash can be prevented by addressing their most common causes. This article serves as a basic troubleshooting guide.

Injection Molding Defects: Causes, Identification, and Prevention

<p dir="ltr">Acrylonitrile Styrene Acrylate (ASA) filament has emerged as a popular choice in 3D printing, particularly for applications demanding both durability and resilience. As a copolymer, ASA combines the properties of acrylonitrile, styrene, and acrylate, resulting in a material that offers superior performance in challenging environments. One of the critical factors influencing ASA’s usability is its glass transition temperature (Tg), which plays a pivotal role in determining the filament's suitability for various applications.</p><p dir="ltr">The ASA glass transition temperature, typically about 100°C depending on the material and testing process, is a measure of the temperature at which the polymer transitions from a rigid, glassy state to a more flexible, rubbery state.[1] This property is crucial for assessing the material’s thermal stability and its ability to maintain structural integrity under heat. A high Tg indicates that ASA can withstand elevated temperatures without significant deformation, making it an ideal choice for parts exposed to heat or thermal cycles.</p><p dir="ltr">Additionally, the ASA glass transition temperature affects its performance in outdoor and high-stress environments. The ability of ASA to retain its mechanical properties and resist deformation at elevated temperatures contributes to its suitability for a range of applications, from automotive components to outdoor equipment.[2] This article goes over the basics of ASA glass transition temperature and its relevance to 3D printing.</p><h2 dir="ltr" data-hhh-border-width="" data-hhh-border-style="" data-hhh-border-color="" data-hhh-background="" style="border-width: 2px; border-style: solid; border-color: rgb(236, 26, 61); background: rgba(236, 26, 61, 0.25);">What is ASA 3D Printing Filament?</h2><p><span class="fr-img-caption fr-fic fr-dib" style="width: 832px;"><span class="fr-img-wrap"><img src="https://images.wevolver.com/eyJidWNrZXQiOiJ3ZXZvbHZlci1wcm9qZWN0LWltYWdlcyIsImtleSI6ImZyb2FsYS8xNzI0ODUwODUzNzc2LTNkX3ByaW50ZWRfZ2VhcnMuanBnIiwiZWRpdHMiOnsicmVzaXplIjp7IndpZHRoIjo5NTAsImZpdCI6ImNvdmVyIn19fQ==" style="width: 100%px;" class="fr-fic fr-dib" alt="asa filament"><span class="fr-inner">ASA filament is comparable in performance to ABS</span></span></span></p><p dir="ltr">Acrylonitrile Styrene Acrylate (ASA) is a widely used thermoplastic in FDM/FFF 3D printing, known for its excellent weather resistance, mechanical strength, and UV stability. Often compared to ABS (Acrylonitrile Butadiene Styrene), ASA offers similar strength and durability but with superior resistance to outdoor conditions, making it ideal for applications that require exposure to sunlight or harsh weather.</p><p dir="ltr">ASA’s UV stability prevents yellowing and degradation, ensuring that parts maintain their color and structural integrity over time. This property makes it a popular choice for automotive components, outdoor fixtures, and any application where prolonged exposure to the elements is a concern. Additionally, ASA is resistant to chemicals and has good impact strength, making it suitable for functional prototypes and end-use parts.</p><p dir="ltr">In terms of printability, ASA is less prone to warping compared to ABS, although it still requires a heated bed and an enclosed build chamber for optimal results. Its slightly lower shrinkage reduces the risk of warping, but careful attention to bed adhesion and temperature control is necessary to minimize these issues. ASA typically prints at temperatures between 240°C and 260°C, with a heated bed set around 90°C to 110°C. The use of an enclosure helps maintain consistent temperature, reducing the likelihood of warping and cracking.</p><p dir="ltr">ASA also supports post-processing, such as sanding, painting, and vapor smoothing, allowing for aesthetically pleasing and functional final products. However, one drawback is the emission of fumes during printing, similar to ABS, which requires adequate ventilation.</p><p dir="ltr"><strong>Recommended reading: <a href="https://www.wevolver.com/article/asa-vs-abs" target="_blank"><em>ASA vs ABS: Finding the right 3D printing filament</em></a></strong></p><h2 dir="ltr" data-hhh-border-width="" data-hhh-border-style="" data-hhh-border-color="" data-hhh-background="" style="border-width: 2px; border-style: solid; border-color: rgb(236, 26, 61); background: rgba(236, 26, 61, 0.25);">ASA Glass Transition Temperature</h2><p dir="ltr">The glass transition temperature (Tg) of Acrylonitrile Styrene Acrylate (ASA) is around 100°C, depending on the material and the testing process. This is a fairly high glass transition temperature compared to other low-cost 3D printing thermoplastics (but low compared to engineering plastics), making ASA particularly suitable for prototyping and low-risk applications where heat resistance and structural integrity are important.</p><p dir="ltr">For comparison, ABS, a close relative of ASA, has a Tg of about 105°C, slightly higher than ASA. Both materials behave similarly during printing, requiring heated beds and enclosed chambers to maintain temperatures above their Tg to ensure proper layer adhesion. However, ASA offers better UV and weather resistance, making it the preferred choice for outdoor applications.</p><p dir="ltr">On the other hand, PLA (Polylactic Acid), another widely used 3D printing material, has a much lower Tg of around 60°C. While PLA is easier to print due to its lower temperature requirements and minimal warping, its lower Tg limits its use in environments where higher temperatures are present. PLA parts can deform or soften under moderate heat, making them unsuitable for outdoor or high-heat applications where ASA would excel.</p><p dir="ltr">Comparatively, materials like PETG (Polyethylene Terephthalate Glycol) have a Tg around 80°C. PETG offers a good balance between ease of printing and heat resistance but lacks the UV stability of ASA, making ASA a better choice for outdoor parts that must endure sunlight and heat without degrading.</p><p dir="ltr">ASA’s Tg ensures that printed parts remain structurally stable and retain their mechanical properties in environments that would challenge lower Tg materials. However, designers must still consider ASA's limitations, ensuring that printed parts do not operate in conditions where temperatures exceed 100°C, as this could lead to softening and loss of strength.</p><h2 dir="ltr" data-hhh-border-width="" data-hhh-border-style="" data-hhh-border-color="" data-hhh-background="" style="border-width: 2px; border-style: solid; border-color: rgb(236, 26, 61); background: rgba(236, 26, 61, 0.25);">Why Does ASA Glass Transition Temperature Vary?</h2><p dir="ltr">The glass transition temperature (Tg) of ASA (Acrylonitrile Styrene Acrylate) can vary due to several factors related to its composition and processing conditions. ASA is a copolymer, meaning it is made from multiple monomers—acrylonitrile, styrene, and acrylate.[3] The ratios of these monomers can affect the Tg. Variations in the proportions can lead to differences in the polymer's rigidity and thermal properties.</p><p dir="ltr">Additionally, the presence of additives or fillers can influence the Tg. These can include impact modifiers, stabilizers, or colorants, each of which can alter the polymer’s thermal behavior. The manufacturing process also plays a crucial role; factors such as polymerization conditions, cooling rates, and thermal history can impact the final Tg. Variability in these conditions can result in slight changes in the Tg from one batch of ASA to another.</p><p dir="ltr">Finally, the Tg can be affected by the molecular weight of the polymer chains. Higher molecular weight ASA may exhibit a different Tg compared to lower molecular weight variants due to differences in chain entanglement and mobility. Thus, the glass transition temperature of ASA is not fixed but rather a range influenced by its specific formulation and processing history.</p><h2 dir="ltr" data-hhh-border-width="" data-hhh-border-style="" data-hhh-border-color="" data-hhh-background="" style="border-width: 2px; border-style: solid; border-color: rgb(236, 26, 61); background: rgba(236, 26, 61, 0.25);">Thermal Properties of Different ASA Filament Brands</h2><p><span class="fr-img-caption fr-fic fr-dib" style="width: 832px;"><span class="fr-img-wrap"><img src="https://images.wevolver.com/eyJidWNrZXQiOiJ3ZXZvbHZlci1wcm9qZWN0LWltYWdlcyIsImtleSI6ImZyb2FsYS8xNzI0Njk2ODI3Mjk0LVAxNTMzMDk0LTEwMjR4NTc3LmpwZyIsImVkaXRzIjp7InJlc2l6ZSI6eyJ3aWR0aCI6OTUwLCJmaXQiOiJjb3ZlciJ9fX0=" style="width: 100%px;" class="fr-fic fr-dib" alt="prusament"><span class="fr-inner">Part made with Prusament ASA material (image credit:&nbsp;<a href="https://prusament.com/materials/prusament-asa/" target="_blank" rel="noopener noreferrer">Prusament</a>)&nbsp;</span></span></span></p><p dir="ltr">When 3D printing ASA filament, the ASA glass transition temperature is not necessarily the main property to focus on. This is due to a number of factors, but mainly because the extrusion temperature of a material is closer to its melting point than its glass transition temperature.</p><p dir="ltr">All filament manufacturers offer recommended printing temperatures for their ASA filament, as well as recommended bed temperatures. But many do not specify the glass transition temperature of the product, as it is less relevant for its end use. The table below shows the slight variations in ASA print settings between filament brands.</p><div dir="ltr" align="left"><table><tbody><tr><td><p dir="ltr"><strong>Brand</strong></p></td><td><p dir="ltr"><strong>Glass Transition Temperature</strong></p></td><td><p dir="ltr"><strong>Recommended Printing Temperature</strong></p></td><td><p dir="ltr"><strong>Recommended Bed Temperature</strong></p></td></tr><tr><td><p dir="ltr">Prusament ASA</p></td><td><p dir="ltr">Not specified</p></td><td><p dir="ltr">255°C - 265°C</p></td><td><p dir="ltr">105°C - 115°C</p></td></tr><tr><td><p dir="ltr">FormFutura ApolloX</p></td><td><p dir="ltr">98°C</p></td><td><p dir="ltr">235°C - 255°C</p></td><td><p dir="ltr">80°C - 100°C</p></td></tr><tr><td><p dir="ltr">Filamentum ASA extrafill</p></td><td><p dir="ltr">Not specified</p></td><td><p dir="ltr">240°C - 255°C</p></td><td><p dir="ltr">80°C - 105°C</p></td></tr><tr><td><p dir="ltr">Polymaker PolyLite ASA</p></td><td><p dir="ltr">97.8°C</p></td><td><p dir="ltr">240°C - 260°C</p></td><td><p dir="ltr">75°C - 95°C</p></td></tr><tr><td><p dir="ltr">eSun ASA</p></td><td><p dir="ltr">Not specified</p></td><td><p dir="ltr">240°C - 270°C</p></td><td><p dir="ltr">90°C - 110°C</p></td></tr></tbody></table></div><h2 dir="ltr" data-hhh-border-width="" data-hhh-border-style="" data-hhh-border-color="" data-hhh-background="" style="border-width: 2px; border-style: solid; border-color: rgb(236, 26, 61); background: rgba(236, 26, 61, 0.25);">High-Temperature Performance of 3D Printed ASA</h2><p dir="ltr">3D printed ASA (Acrylonitrile Styrene Acrylate) is known for its good temperature resistance and UV resistance for its price point, making it a preferred material for outdoor and high-temperature applications. This property is also particularly advantageous for parts that undergo thermal cycling.</p><p dir="ltr">In terms of UV resistance, ASA excels compared to other common 3D printing materials like ABS. ASA’s chemical composition includes a high level of acrylate, which provides better protection against UV degradation. This makes ASA highly resistant to yellowing and physical degradation when exposed to sunlight, ensuring that printed parts retain their mechanical properties and aesthetic appearance over time. The inherent UV stability of ASA is beneficial for outdoor applications, such as automotive parts, construction components, and various outdoor equipment.</p><p dir="ltr">To enhance the heat resistance of ASA 3D prints, consider the following strategies:</p><h3 dir="ltr" data-hhh-border-width="" data-hhh-border-style="" data-hhh-border-color="" data-hhh-background="" style="border-width: 2px; border-style: solid; border-color: rgb(52, 153, 137); background: rgba(52, 153, 137, 0.25);">Optimize Print Settings</h3><p dir="ltr">Increase the extrusion temperature and print bed temperature to ensure better layer adhesion and reduce internal stresses. A higher nozzle temperature (typically between 240°C and 260°C) ensures the material is fully fused, leading to stronger, more heat-resistant prints. Slower print speeds can also improve inter-layer bonding, contributing to overall thermal stability.</p><h3 dir="ltr" data-hhh-border-width="" data-hhh-border-style="" data-hhh-border-color="" data-hhh-background="" style="border-width: 2px; border-style: solid; border-color: rgb(52, 153, 137); background: rgba(52, 153, 137, 0.25);">Annealing</h3><p dir="ltr">Post-process the ASA print by annealing it in an oven. Heating the print to a temperature just below the glass transition temperature (around 85°C to 95°C) for a few hours can relieve internal stresses and improve the crystallinity of the polymer. This process can enhance the print’s thermal resistance and dimensional stability when exposed to higher temperatures.</p><h3 dir="ltr" data-hhh-border-width="" data-hhh-border-style="" data-hhh-border-color="" data-hhh-background="" style="border-width: 2px; border-style: solid; border-color: rgb(52, 153, 137); background: rgba(52, 153, 137, 0.25);">Infill and Wall Thickness Adjustment</h3><p dir="ltr">Increase the infill percentage and wall thickness to reinforce the print. A denser infill and thicker walls create a more robust structure that can better resist deformation under heat. Additionally, using a higher number of perimeters can enhance the print’s rigidity, making it less susceptible to warping or softening when exposed to elevated temperatures.</p><p dir="ltr"><strong>Recommended reading: <a href="https://www.wevolver.com/article/what-is-pla-filament-composition-advantages-applications" target="_blank"><em>What is PLA Filament? Composition, Advantages, Applications</em></a></strong></p><h2 dir="ltr" data-hhh-border-width="" data-hhh-border-style="" data-hhh-border-color="" data-hhh-background="" style="border-width: 2px; border-style: solid; border-color: rgb(255, 210, 63); background: rgba(255, 210, 63, 0.25);">Conclusion</h2><p><span class="fr-img-caption fr-fic fr-dib" style="width: 832px;"><span class="fr-img-wrap"><img src="https://images.wevolver.com/eyJidWNrZXQiOiJ3ZXZvbHZlci1wcm9qZWN0LWltYWdlcyIsImtleSI6ImZyb2FsYS8xNzI0ODUwODc5MzQzLWdyZWVuX2Nhcl9zaWRlX21pcnJvci5qcGciLCJlZGl0cyI6eyJyZXNpemUiOnsid2lkdGgiOjk1MCwiZml0IjoiY292ZXIifX19" style="width: 100%px;" class="fr-fic fr-dib" alt="car"><span class="fr-inner">ASA's UV resistance makes it suitable for external car parts like mirror housings</span></span></span></p><p dir="ltr">ASA's glass transition temperature (Tg) is an important parameter that influences its mechanical, thermal, and chemical properties. Understanding Tg is helpful for optimizing ASA's performance in diverse engineering applications, from automotive exteriors to electronic housings. However, ordinary 3D printer users should focus on a material’s suggested printing temperature rather than its glass transition temperature to achieve a high level of printing performance.</p><h2 dir="ltr" data-hhh-border-width="" data-hhh-border-style="" data-hhh-border-color="" data-hhh-background="" style="border-width: 2px; border-style: solid; border-color: rgb(255, 210, 63); background: rgba(255, 210, 63, 0.25);">Frequently Asked Questions (FAQ)</h2><p dir="ltr"><strong>What is the ASA glass transition temperature?</strong></p><p dir="ltr">The glass transition temperature of ASA is around 100°C.</p><p dir="ltr"><strong>What is the ideal printing temperature for ASA?</strong></p><p dir="ltr">ASA filament prints best at an extrusion temperature of around 250°C and a bed temperature of around 100°C.</p><p dir="ltr"><strong>How does ASA compare to ABS?</strong></p><p dir="ltr">ASA has a slightly lower glass transition temperature than ABS. It is therefore fractionally less heat resistant but offers superior UV and water resistance.</p><p dir="ltr"><strong>What are some popular ASA filaments?</strong></p><p dir="ltr">Common ASA filament brands include FormFuture ApolloX, Filamentum ASA extrafill, and Polymaker PolyLite ASA.</p><h2 dir="ltr" data-hhh-border-width="" data-hhh-border-style="" data-hhh-border-color="" data-hhh-background="" style="border-width: 2px; border-style: solid; border-color: rgb(255, 210, 63); background: rgba(255, 210, 63, 0.25);">References</h2><p dir="ltr">[1] Shen MC, Eisenberg A. <a href="https://www.sciencedirect.com/science/article/abs/pii/0079678667900398" target="_blank">Glass transitions in polymers</a>. Rubber Chemistry and Technology. 1970 Jan 1;43(1):95-155.</p><p dir="ltr">[2] Berzinis A, Andriuli M. <a href="https://www.sae.org/publications/technical-papers/content/1999-01-0847/" target="_blank">Weathering performance of black thermoplastic resins for unpainted automotive exterior applications</a>. SAE transactions. 1999 Jan 1:706-15.</p><p dir="ltr">[3] Breulmann M. <a href="https://www.researchgate.net/publication/230137160_Synthesis_Properties_and_Applications_of_Acrylonitrile-Styrene-Acrylate_Polymers" target="_blank">Synthesis, Properties and Applications of Acrylonitrile±Styrene±Acrylate Polymers</a>. Modern Styrenic Polymers: Polystyrenes and Styrenic Copolymers. 2003 Mar 1:341.</p>

The ASA glass transition temperature is around 100°C. This makes it slightly easier to print than ABS, while it is also better for outdoor applications due to its good UV resistance.

ASA Glass Transition Temperature & Its Impact on 3D Printing

Explore the latest advancements in extruding plastic and its impact on modern engineering, covering foundational concepts, cutting-edge innovations, and key challenges in this dynamic field. 

Extruding Plastic: Mastering Advanced Techniques and Innovations

The global surge in thermoplastics demand has led to increased production and plastic waste, surpassing annual production levels, necessitating the development of sustainable recycling methods and practices throughout the product life cycle to mitigate environmental impacts.

Engineering Thermoplastics Guide. Chapter 6. Sustainability and Recycling of Engineering Thermoplastics

Helmet made with KyronTEX®, a continuous carbon fiber-reinforced thermoplastic composite. Source: Mitsubishi Chemical Group

Composites are materials composed of a matrix and reinforcement, offering unique advantages and properties derived from both components.

Engineering Thermoplastics Guide. Chapter 5. Thermoplastic Composites and Their Applications

<p>This is an excerpt from Chapter 3 of The Engineering Thermoplastics Guide. Download the full guide below for the full text, including technical diagrams and application notes.&nbsp;</p><p><img src="https://images.wevolver.com/eyJidWNrZXQiOiJ3ZXZvbHZlci1wcm9qZWN0LWltYWdlcyIsImtleSI6ImZyb2FsYS8xNzA5ODEzNTYzNTYxLTMucG5nIiwiZWRpdHMiOnsicmVzaXplIjp7IndpZHRoIjo5NTAsImZpdCI6ImNvdmVyIn19fQ==" style="width: 100%px;" class="fr-fic fr-dib"></p><h2 dir="ltr"><span contenteditable="false" draggable="true" class="fr-video fr-deletable fr-fvc fr-dvb fr-draggable"><iframe width="540" height="700" src="https://c8056756.sibforms.com/serve/MUIFALhRx-pzB3WdCribJmgCdXRujbxbHx5nFTSwlI1hMI0Myb_EyFY_vhDjBDRPcymlHRNBCzvC-fQiSkGEQkoK8kgTHL3zmqclwy-WxYt1Os2RIjdQNPC5WmiKyhwzIXNwBHCep72gg8nmirJN2B4QVCiyglK7g-2fJEtOqlsvDmuRlSiVlE1F0VvwivibRK_weMJrZESJHGfe" frameborder="0" scrolling="auto" allowfullscreen="" style="display: block;margin-left: auto;margin-right: auto;max-width: 100%;" class="fr-draggable" data-lf-form-tracking-inspected-kn9eq4roawkarlvp="true" data-lf-yt-playback-inspected-kn9eq4roawkarlvp="true" data-lf-vimeo-playback-inspected-kn9eq4roawkarlvp="true"><span class="fr-mk" style="display: none;">&nbsp;</span></iframe></span></h2><h2 dir="ltr" id="isPasted">Introduction</h2><p dir="ltr">&nbsp;Since the early days of thermoplastic materials science, continued research and innovation have been driving the industry. Throughout the decades, this has led to the discovery of materials with unprecedented properties. In the 1930s, for example, the discovery of nylon substituted the use of silk in consumer goods and military applications. In the 1960s, continued research in materials science led to the discovery of Kevlar, a material with an outstanding strength five times greater than steel.</p><p dir="ltr">Today, research in the field of thermoplastics is focused both on the exploration of new formulations, like thermoplastic elastomers and liquid crystal polymers, and on the development of new processing methods, capable of expanding the technological possibilities of these materials. Smart and responsive materials and composites are also pushing the boundaries of thermoplastic technology.</p><p dir="ltr">In this chapter, you will learn about the latest advancements in thermoplastics materials science and processing technology.</p><h2 dir="ltr">New Formulations and Polymer Chemistry</h2><p dir="ltr">One of the most interesting features of thermoplastics is the wide diversity of their chemical structures and formulations. Today, research in materials science and engineering is uncovering new thermoplastic materials with unique properties for advanced applications.</p><p dir="ltr">Thermoplastic elastomers (TPEs) are a versatile family of polymeric materials that exhibit thermoplastic processability while retaining elastomeric characteristics traditionally associated with thermoset rubbers. The composition of TPEs involves the block copolymerization of molecularly dissimilar polymers, resulting in the creation of "hard" and "soft" segments within the polymer chain. The mechanical properties of these materials are dictated by their molecular composition.</p><p dir="ltr">Noteworthy TPE types include:</p><ul><li dir="ltr"><p dir="ltr">TPE-S, whose molecular structure consists of repeated styrene and butadiene units;</p></li><li dir="ltr"><p dir="ltr">TPO, a blend of polypropylene or polyethylene with another elastomer;</p></li><li dir="ltr"><p dir="ltr">TPE-E, high-performance thermoplastic elastomers consisting of polybutylene terephthalate combined with polyesters.</p></li></ul><p dir="ltr">TPEs offer many advantages over regular elastomers, including reduced energy consumption during production, recyclability, and improved mechanical properties such as strength and creep resistance. Additionally, TPEs are easily processed through standard thermoplastic techniques like injection molding, 3D printing, and blow molding.</p><p dir="ltr">Common applications of TPEs span across various industries, including electronics (condenser sheaths, plugs, and sockets), and medical devices, such as breathing tubes, syringe seals, ventilation masks, and catheters. <sup>[1]</sup></p><p dir="ltr">Liquid Crystal Polymers (LCPs) are a distinctive class of materials that can maintain molecular order in both liquid and solid states. LCPs exhibit two distinct phase changes: the transition from solid to liquid crystal and, subsequently, the transition from liquid crystal to full liquid. The intermediate phase is also known as mesophase. LCPs are categorized as either lyotropic, processed by solvent addition, or thermotropic, melt-processable like conventional thermoplastics.</p><p dir="ltr">Three of the most common forms of liquid crystal polymers include semi-aromatic copolyesters, copolyamides, and polyester-co-amides. The aromatic amide polymer Kevlar is one the most well-known examples of an LCP. Due to its outstanding strength and toughness, superior to almost any other synthetic fiber, it is used for bulletproof vests, aerospace materials, sporting goods, and other highly demanding applications.</p><p dir="ltr">During processing, the rod-like molecules of LCPs align in a specific direction, resulting in anisotropic mechanical properties. In general, these materials possess outstanding strength, excellent temperature, flame, and chemical resistance, and optimal dimensional stability. The remarkable combination of strength, stiffness, low shrinkage, and stability makes LCPs a preferred material in diverse applications. In electronics, LCPs find use in connectors, switches, and displays. Medical applications include dentistry and micro-surgery. <sup>[1]</sup></p><p dir="ltr">Continued innovation and research are pivotal for advancing thermoplastic materials science. One recent groundbreaking development is 2DPA-1, a 2D polyaramide material obtained through an innovative polymerization process by researchers at MIT in 2022. 2DPA-1 exhibits remarkable properties, including an elastic modulus four to six times greater than bulletproof glass and a yield strength twice that of steel, despite being one-sixth as dense. The mechanical properties of this novel material, combined with its low gas and water permeability, make it a promising candidate for advanced applications such as ultrathin coatings in engineering and aerospace. <sup>[13]</sup></p><h2 dir="ltr">Hybrid processing technology</h2><p dir="ltr">A notable advancement in thermoplastic processing technology is the use of 3D printing to craft continuous fiber-reinforced composites. While the additive manufacturing of short fiber-reinforced thermoplastics is already well-established, the 3D printing of long fiber-reinforced composites presents additional challenges.</p><p dir="ltr">Today, several technologies are being developed for 3D printing continuous fiber-reinforced composites. These hybrid processing approaches hold the potential to significantly improve part quality and performance while reducing production costs. The demand for printers capable of fabricating continuous fiber-reinforced plastics is high, promising substantial cost-savings and increased automation in the field of composites.</p><p dir="ltr">This technology holds promise for diverse applications, including the automotive and aerospace sectors, custom products like orthopedic implants, and prosthetic limbs in healthcare. Replacing traditional labor-intensive manufacturing with 3D printing is a transformative shift leading to a new generation of thermoplastic composites. <sup>[14]</sup></p><p dir="ltr">Overmolding with thermoplastic composites represents another significant step forward in composite manufacturing. It allows the production of complex 3D structures with exceptional structural performance and high functional integration.</p><p dir="ltr">Overmolding technology is a processing method that allows the combination of two distinct materials into a unique component. Typically, it involves thermoforming a first material (thermoplastic or thermoplastic composite), followed by injection molding of a second material.</p><p dir="ltr">The overmolding process can significantly reduce production times and costs, particularly in aerospace and automotive applications. With its short cycle times, it enables the combination of characteristics from two or more materials without the need for mechanical interlocking or adhesive bonding, eliminating assembly steps.</p><p dir="ltr">Overmolding can be used to combine composite materials and other thermoplastics, or thermoplastic materials with thermosets, obtaining hybrid and multifunctional components for versatile applications. The main challenge of overmolding is optimizing the adhesion while preventing interdiffusion between the two different material layers. To address this challenge, new adhesive technologies, based on nanomaterials, are currently being developed. <sup>[15]</sup></p><p dir="ltr">Large-scale additive manufacturing (AM) technologies have revolutionized various industries, from aerospace to construction, by unlocking the versatility of 3D printing in unprecedented applications. While traditional 3D printers have limitations in terms of print volumes and deposition rates, there is a growing focus on overcoming these constraints to facilitate the manufacturing of larger components.</p><p dir="ltr">The emergence of large-format additive manufacturing (LFAM) promises increased speed, precision, mechanical strength, and customization in the production of complex, lightweight, large-scale geometries. LFAM can be adapted to different additive manufacturing methods including both powder bed fusion and extrusion-based systems.</p><p dir="ltr">Pellet-based technologies within fused filament fabrication (FFF) have also emerged as a notable advancement, offering reduced production times and material costs, as well as the flexibility to use a wide array of materials, including composites. These innovations in LFAM overcome the limitations of conventional 3D printing, paving the way for efficient and cost-effective large-scale manufacturing across diverse sectors. <sup>[16]</sup></p><h2 dir="ltr">Towards “smarter” thermoplastic materials</h2><p dir="ltr">Smart thermoplastics are a fascinating class of modern materials designed to respond to external stimuli by changing their shape and properties. Among these materials, shape-memory polymers, or SMPs, stand out for their ability to memorize a specific shape and recover their original form upon exposure to an external stimulus, commonly heat.</p><p dir="ltr">This “smart” behavior and the advantages of low density, easy processing, and cost-effectiveness provided by thermoplastics make SMPs promising candidates for various applications. Unlike thermosets, thermoplastic SMPs are processed quickly and cheaply using conventional thermoplastic technology.</p><p dir="ltr">Notably, some SMPs can be 3D printed with conventional FFF printers. PLA, for example, is a well-known polylactic acid used in additive manufacturing that also possesses shape-memory properties. A combination of SMPs with new design strategies, such as origami and bio-inspired structures, can result in responsive components.</p><p dir="ltr">The integration of 3D printing and SMPs has led to the emergence of "4D printing," enabling printed structures to actively change configurations over time in response to environmental stimuli like heat or humidity. This innovative technology holds significant promise for applications such as minimally invasive biomedical devices, such as stents and dilators. <sup>[17]</sup></p><p dir="ltr">Another example of “smart” materials is self-healing thermoplastics. The quest for materials&nbsp;<iframe id="658c169a0dcd607468281120" width="250" class="specs-iframe" height="440" src="https://wevolver.com/iframe/specs/electrostatic-dissipative-plastics?iframe=true" frameborder="0" scrolling="no" data-lf-form-tracking-inspected-kn9eq4roawkarlvp="true" data-lf-yt-playback-inspected-kn9eq4roawkarlvp="true" data-lf-vimeo-playback-inspected-kn9eq4roawkarlvp="true"><span class="fr-mk" style="display: none;">&nbsp;</span></iframe> with self-healing capabilities has gained substantial attention in the past 15 years, particularly for applications in aerospace, electronics, robotics, and sporting goods. The ability of materials to autonomously repair damage holds significant promise for enhancing longevity, reducing replacement costs, and improving safety. Structural polymer materials and composites are prone to damage and degradation, with cracks often forming deep within the structure. Detecting and repairing such cracks pose considerable challenges.</p><p dir="ltr">Self-healing thermoplastics offer an alternative solution, allowing for the spontaneous repair of degraded and cracked structures. These materials are broadly categorized as intrinsic or extrinsic self-healing systems, depending on the repair mechanism. Extrinsic self-healing requires the incorporation of additional materials. Intrinsic self-healing thermoplastics, on the other hand, can autonomously heal themselves, triggered by stimuli such as heat, light, or static load.</p><p dir="ltr">Among self-healing materials, thermoplastic elastomers and nanocomposites containing graphene and carbon nanotubes have shown great promise in various engineering applications, spanning from electronics to robotics. This technology represents a ground-breaking advancement in materials science, offering the potential to revolutionize how we approach durability and maintenance in diverse industries. <sup>[18]</sup></p><h2 dir="ltr">Looking towards the future</h2><p dir="ltr">In conclusion, the evolution of thermoplastic materials is being improved by remarkable new research and industry advancements. The contemporary landscape of thermoplastics is characterized by a rich diversity of formulations, including the emergence of thermoplastic elastomers and liquid crystal polymers, bringing unique properties and applications.</p><p dir="ltr">The quest for innovation extends to hybrid processing technologies, such as 3D printing for&nbsp;<iframe id="658c145b19c288d51ecbf006" width="250" class="specs-iframe" height="440" src="https://wevolver.com/iframe/specs/life-science-grade-thermoplastic-materials?iframe=true" frameborder="0" scrolling="no" data-lf-form-tracking-inspected-kn9eq4roawkarlvp="true" data-lf-yt-playback-inspected-kn9eq4roawkarlvp="true" data-lf-vimeo-playback-inspected-kn9eq4roawkarlvp="true"><span class="fr-mk" style="display: none;">&nbsp;</span></iframe> continuous fiber-reinforced composites, large-format additive manufacturing, and overmolding. These new technologies further enhance the versatility, applicability, and potential of thermoplastic materials. Recent breakthroughs in thermoplastic research, such as self-healing and shape-memory polymers, are paving the way for new applications of thermoplastics in engineering, medicine, and aerospace.</p><p dir="ltr">Looking forward, the future of thermoplastic research holds exciting possibilities. Integration of thermoplastics with nanomaterials, such as carbon nanotubes, graphene, and silica nanoparticles, can exponentially improve the mechanical and functional properties of composites. Additionally, the rise of biodegradable, bio-derived, and recycled plastics is bringing the thermoplastics industry in alignment with global sustainability goals.</p><hr><p>You have just been reading an excerpt from Chapter 4 of The Engineering Thermoplastics Guide. Download the full guide below for the full text, including technical diagrams and application notes.&nbsp;</p><p><span contenteditable="false" draggable="true" class="fr-video fr-deletable fr-fvc fr-dvb fr-draggable"><iframe width="540" height="700" src="https://c8056756.sibforms.com/serve/MUIFALhRx-pzB3WdCribJmgCdXRujbxbHx5nFTSwlI1hMI0Myb_EyFY_vhDjBDRPcymlHRNBCzvC-fQiSkGEQkoK8kgTHL3zmqclwy-WxYt1Os2RIjdQNPC5WmiKyhwzIXNwBHCep72gg8nmirJN2B4QVCiyglK7g-2fJEtOqlsvDmuRlSiVlE1F0VvwivibRK_weMJrZESJHGfe" frameborder="0" scrolling="auto" allowfullscreen="" style="display: block;margin-left: auto;margin-right: auto;max-width: 100%;" class="fr-draggable" data-lf-form-tracking-inspected-kn9eq4roawkarlvp="true" data-lf-yt-playback-inspected-kn9eq4roawkarlvp="true" data-lf-vimeo-playback-inspected-kn9eq4roawkarlvp="true"><span class="fr-mk" style="display: none;">&nbsp;</span></iframe></span></p>


Ongoing research in thermoplastic materials science since its inception has led to groundbreaking discoveries like nylon and Kevlar, and now focuses on innovative formulations and processing methods, pushing technological boundaries, as explored in this chapter on the latest advancements.

Engineering Thermoplastics Guide. Chapter 4: Advancements in Thermoplastic Materials Science

<p>This is an excerpt from Chapter 3 of The Engineering Thermoplastics Guide. Download the full guide below for the full text, including technical diagrams and application notes.&nbsp;</p><p><img src="https://images.wevolver.com/eyJidWNrZXQiOiJ3ZXZvbHZlci1wcm9qZWN0LWltYWdlcyIsImtleSI6ImZyb2FsYS8xNzA4MzUwMjMwNDM3LTMucG5nIiwiZWRpdHMiOnsicmVzaXplIjp7IndpZHRoIjo5NTAsImZpdCI6ImNvdmVyIn19fQ==" style="width: 300px;" class="fr-fic fr-dib"></p><p><span contenteditable="false" draggable="true" class="fr-video fr-deletable fr-fvc fr-dvb fr-draggable"><iframe width="540" height="700" src="https://c8056756.sibforms.com/serve/MUIFALhRx-pzB3WdCribJmgCdXRujbxbHx5nFTSwlI1hMI0Myb_EyFY_vhDjBDRPcymlHRNBCzvC-fQiSkGEQkoK8kgTHL3zmqclwy-WxYt1Os2RIjdQNPC5WmiKyhwzIXNwBHCep72gg8nmirJN2B4QVCiyglK7g-2fJEtOqlsvDmuRlSiVlE1F0VvwivibRK_weMJrZESJHGfe" frameborder="0" scrolling="auto" allowfullscreen="" style="display: block;margin-left: auto;margin-right: auto;max-width: 100%;" class="fr-draggable" data-lf-form-tracking-inspected-kn9eq4roawkarlvp="true" data-lf-yt-playback-inspected-kn9eq4roawkarlvp="true" data-lf-vimeo-playback-inspected-kn9eq4roawkarlvp="true"><span class="fr-mk" style="display: none;">&nbsp;</span></iframe></span></p><h2 id="isPasted">Introduction</h2><p>While thermoplastics possess several attractive properties, such as low weight, low cost, ease of processability, and design freedom, the applications of unmodified plastics are limited. For example, most thermoplastics possess lower mechanical strength, lower resistance to UV radiation, and lower conductivity compared to metals. In order to increase the applicability of thermoplastics across various industries, these properties must be enhanced.</p><p>Reinforcing additives, like chemical substances, can be added to thermoplastics to improve the behavior of the product throughout its lifespan. They are mechanically dispersed within the polymer matrix, contributing significantly to the overall performance of the material. The addition of additives can improve many properties of thermoplastic products, including mechanical behavior, tribological properties, thermal and UV resistance, chemical stability, fire retardancy, resistance to electromagnetic interference, and electrostatic dissipation.<sup>[9]</sup></p><p>This chapter excerpt offers an overview of common additives for thermoplastics and illustrates their applications.</p><h2>Understanding the Need for Enhancement</h2><p>Despite their versatility, the applicability of thermoplastics is limited in many contexts due to the intrinsic challenges of these materials. Although the mechanical and tribological properties of thermoplastics vary widely depending on the type of material, with advanced thermoplastics exhibiting much higher strength and toughness, standard unmodified thermoplastics can be unsuitable for many demanding applications.&nbsp;</p><p>UV resistance is another issue with thermoplastics. Due to their organic nature, polymers can be prone to chemical degradation as a result of long exposure to light and atmospheric conditions. This can lead to loss of aesthetic appeal, such as discoloration, as well as a reduction of functional properties. Similarly, the organic composition of thermoplastics, which are mostly composed of carbon, hydrogen, and oxygen, often makes them susceptible to combustion.&nbsp;</p><p>Lastly, most thermoplastics are not suitable for applications where electrostatic discharges (ESD) can be an issue. This is because these materials are insulators and are unable to dissipate electric charge. In the electronics and semiconductor industries, ESD phenomena can lead to serious damage to expensive components. Many unmodified thermoplastics are also transparent to electromagnetic radiation, resulting in interference issues when these materials are used in electronic devices.</p><p>For these reasons, thermoplastics are often enhanced with fillers and additives to improve their mechanical, chemical, thermal, and electrical properties. With new enhancement strategies, these versatile materials are adapting to an increasing number of unprecedented applications.&nbsp;</p><h2>Performance Enhancement Strategies</h2><h3>Mechanical Reinforcement (Fillers)</h3><p>Fillers play a crucial role in enhancing the mechanical and functional properties of commodity, engineering, and advanced thermoplastics. Typically, fillers are inorganic solid materials of small size (&lt;100 microns) added in a relatively large volume fraction to the matrix. They are incorporated into thermoplastic products to improve their stiffness, impact strength, appearance, conductivity, and flammability, making them highly versatile in adjusting material properties for specific applications.</p><p>While initially used as extenders to reduce the cost of plastic products, modern fillers, known as “functional fillers”, are primarily focused on enhancing functionality, with a specific effect on mechanical properties. Stiffness, toughness, strength, and modulus can all be improved thanks to the addition of specific fillers. Tribological features of plastics are also improved by the addition of inorganic fillers. This results in enhanced wear and friction resistance properties under dynamic conditions. <sup>[9]</sup></p><p>Despite the advantages they offer, achieving effective filler dispersion in polymers can be challenging. A homogeneous distribution of the fillers is important to achieve the desired properties. While fillers are typically inorganic and hydrophilic, plastic matrices are organic and often hydrophobic. Because of this, compatibilization via specific additives is crucial.</p><p>The influence of fillers on the mechanical properties of thermoplastics depends on their nature, size, shape, and distribution, as well as their impact on the matrix's microstructure. Among the fillers used in thermoplastic products, glass fiber, carbon fiber, and graphite are some of the most widely used.&nbsp;<iframe id="658adb327202f60e7ac2ea81" width="250" class="specs-iframe" height="440" src="https://wevolver.com/iframe/specs/plastic-lining-materials-that-handle-bulk-materials?iframe=true" frameborder="0" scrolling="no" data-lf-form-tracking-inspected-kn9eq4roawkarlvp="true" data-lf-yt-playback-inspected-kn9eq4roawkarlvp="true" data-lf-vimeo-playback-inspected-kn9eq4roawkarlvp="true"></iframe></p><p>Glass fiber is the most commonly employed filler due to its cost-effectiveness and capacity to enhance strength and impact resistance while offering chemical resistance and low weight. The addition of glass fiber results in materials with high flexural and tensile strength. Carbon fiber, despite its higher cost compared to glass, has become a staple functional filler in high-performance thermoplastics, with continuously growing demand. In addition to improving mechanical properties, carbon fiber can also enhance thermal and electrical conductivity. &nbsp;Compared to glass fiber-filled thermoplastics, carbon fiber-filled materials are also suitable for dynamic applications, where they do not abradeact abrasive towards the mating counter part. Glass and carbon fiber can also be mixed resulting in hybrid reinforcement systems. <sup>[1]</sup></p><p>Graphite, when added to thermoplastics, can significantly impact both mechanical and tribological features, making it a versatile choice for tailored applications. Due to its improved thermal conductivity and nonflammability, graphite is an ideal filler in industrial applications where high heat dissipation is needed.</p><h2>Important parameters for the selection of fillers in thermoplastic materials.</h2><h3>UV Stabilizers</h3><p>UV stabilizing additives are crucial for preserving the integrity and longevity of thermoplastic products exposed to sunlight. When polymers are subjected to light, they undergo photooxidative degradation in the presence of air. The absorbed light initiates photochemical reactions, particularly affecting specific chemical groups within the material known as chromophores. This can lead to loss of mechanical and functional properties.</p><p>The specific sensitivity of each thermoplastic to radiation depends on the material’s chemical structure. In particular, weaker chemical bonds undergo more pronounced degradation. Double bonds also tend to interact more strongly with light. In addition, photosensitive groups can be introduced as impurities during manufacturing. In general, due to their microstructure, semi-crystalline thermoplastics tend to exhibit increased sensitivity to light. <sup>[9]</sup></p><p>UV stabilizers are essential in combating UV-induced degradation by absorbing and safely<iframe id="658c0c17910805d4ce694468" width="250" class="specs-iframe" height="440" src="https://wevolver.com/iframe/specs/vmx-detectable-plastics-for-food-processing-units?iframe=true" frameborder="0" scrolling="no" data-lf-form-tracking-inspected-kn9eq4roawkarlvp="true" data-lf-yt-playback-inspected-kn9eq4roawkarlvp="true" data-lf-vimeo-playback-inspected-kn9eq4roawkarlvp="true"></iframe> dissipating ultraviolet radiation, thus protecting the material. These stabilizers typically consist of organic molecules with tailored photochemical properties, although inorganic fillers such as carbon black can also improve UV resistance. UV stabilizers are particularly crucial for plastics exposed to outdoor conditions, as they prevent the aging process and protect against discoloration. Additionally, UV stabilizers play a vital role in safeguarding the contents of packaged goods from degradation due to UV light exposure.<sup>&nbsp;[10]</sup></p><h3>Antioxidants</h3><p>During processing and use at high temperatures, thermoplastics are susceptible to a process known as auto-oxidation, caused by the spontaneous formation of free radicals. This can lead to a loss of mechanical and functional properties over time. For this reason, antioxidants play an important role in preserving the quality and extending the service life of thermoplastic materials by inhibiting their oxidative and thermal degradation processes.</p><p>These additives act as radical scavengers, retarding or preventing degradation during various stages, including processing, handling, and long-term use. They effectively interrupt the chain propagation steps in auto-oxidation reactions. Antioxidants must possess specific characteristics to effectively protect the material, such as resistance to degradation, easy incorporation into the polymer, and resistance to evaporation or leaching. These additives are typically categorized into primary and secondary antioxidants. <sup>[9]</sup>&nbsp;</p><p>Primary antioxidants, also known as chain breakers, are radical scavengers or hydrogen donors, and they include organic molecules such as hindered phenols and secondary amines. These molecules directly stop the free radical propagation. Secondary antioxidants, on the other hand, are peroxide decomposers. They turn these highly reactive molecules into less harmful compounds. Often, these two kinds of additives are combined to maximize their efficacy. <sup>[10]</sup></p><h3>Flame Retardants</h3><p>Flame retardant additives play a crucial role in enhancing the fire resistance of thermoplastics, addressing their inherent flammability issues. In fact, most plastics are prone to easy ignition due to their chemical composition, primarily consisting of carbon and hydrogen.</p><p>A common measure for flammability is the limiting oxygen index (LOI), which quantifies the percentage of oxygen required in the atmosphere to sustain combustion under standardized conditions. While materials with an LOI below 21% burn easily, thermoplastics with an LOI between 21% and 28% are slow-burning, and those with an LOI above 28% are inherently fire extinguishing.</p><h3>LOI of common thermoplastics</h3><p>While most advanced thermoplastics exhibit inherent fire resistance, many plastics are known for their high flammability, often accompanied by the release of corrosive or toxic gases and smoke during combustion. Thus, improving the fire retardant behavior of thermoplastic products is essential for expanding their applicability across various industries.</p><p>Flame retardants can act through various mechanisms, such as inhibiting reactive radicals, reducing heat generation via endothermic reactions, or forming thermally insulating char layers on the plastic’s surface. The most widely used flame retardants are halogenated compounds.</p><p>While halogen-based flame retardants have historically dominated the market, the primary challenge today revolves around their substitution with more environmentally friendly options. Among these, phosphorous and metal hydroxide flame retardants are sustainable and effective halogen-free solutions. <sup>[11]</sup></p><h3>Electrical Properties Enhancers (Conductivity and ESD)</h3><p>Electrostatic discharge (ESD) can be a significant issue with plastics due to their inherent electrical insulating properties. This can result in the accumulation of strong electrostatic charges that may disrupt or damage sensitive electronic components. To mitigate this issue, antistatic additives can be employed to enhance the electrical properties of thermoplastics.</p><p>ESD resistance enhancers can be classified into two main types: internal and external. Internal antistatic additives create a conductive path within the plastic, allowing for the rapid dissipation of electrostatic charges. On the other hand, external antistatic agents are applied to the surface of the material after processing and require minimal dosages. However, these external treatments may not be suitable for long-lasting applications due to potential issues with adhesion.</p><p>Internal antistatic additives are directly blended with the thermoplastic material during processing. Typically, these additives are inorganic fillers such as carbon black, carbon fiber, or metal powders. Thermoplastics with inherent conductivity, such as conducting polymers –-- also known as IDP (inherently dissipative polymers) –, may also be utilized to produce antistatic products. [9]</p><h3>EMI Shielding Attributes</h3><p>EMI (Electromagnetic interference) shielding is essential for preventing the passage of electromagnetic waves into or out of electronic devices. In many contexts, these interferences can cause serious issues with the correct functioning of electronic systems.</p><p>Most thermoplastics are naturally transparent to electromagnetic radiation. Because of this, metals have been traditionally employed as shielding materials. However, switching to plastics can lead to diminished costs, weight reduction, ease of production, and improved design freedom.</p><p>To address the inherent lack of EMI shielding in thermoplastics, various methods have been developed. These methods aim to enhance the electrical conductivity of plastics through approaches such as conductive coatings, compounding with conductive fillers, and using intrinsically conductive polymers (ICPs).</p><p>Conductive coatings, including metallic plating, are effective but require additional surface preparation and equipment. On the other hand, compounding with additives like carbon black, carbon fibers, stainless steel fibers, and aluminum can lead to optimal EMI shielding properties. The use of these fillers favors the increasing integration of thermoplastic materials into the electronics industry. <sup>[12]</sup></p><h3>Coloring agents</h3><p>Coloring additives, including dyes and pigments, play a crucial role in enhancing the aesthetic appeal of thermoplastic products. Dyes are soluble organic compounds, while pigments can be either organic or inorganic but are typically insoluble. Certain pigments, such as carbon black, provide extra benefits beyond coloring, including UV protection, reinforcement, and improved electrostatic properties.</p><p>However, it's worth noting that some pigments and dyes can affect the photostability of thermoplastics by increasing their sensitivity to light. Pigments, especially in standard plastics such as polyethylene and polypropylene, may impact the molecular structure of the material, leading to a loss of dimensional stability. Therefore, pigments and dyes should be selected carefully depending on the material and the final application. <sup>[10]</sup></p><h2>Uses of Enhanced Thermoplastics</h2><p>Enhanced thermoplastics can find applications in many demanding industrial sectors where other materials, such as metals, were previously used. Reinforcement of advanced thermoplastics with fillers such as carbon fiber, graphite, and glass fiber can lead to outstanding mechanical and tribological properties. These enhanced materials can be used in the most challenging applications such as the aerospace industry.&nbsp;</p><p>For example, MCG’s Duratron® T4301 PAI is an advanced thermoplastic with low-friction properties. It is enhanced with a graphite filler, providing exceptional reinforcement and wear resistance for labor-intensive components. This graphite-filled advanced material was employed in aircraft wing flaps, providing long-term endurance to wear, weight reduction, and optimal thermal and chemical resistance.&nbsp;</p><p>Improved electrostatic dissipation is crucial in the electronics and semiconductor industries. However, thermoplastics with enhanced ESD properties can also be employed in other industrial sectors to prevent the buildup of electrostatic charge and facilitate the flow of dusty materials. MCG’s TIVAR® 88-2 ESD is an electrostatic dissipative UHMW-PE material. Thanks to its optimal electrical and chemical properties, this material was used to substitute steel in silo liners for the bio-coal industry, leading to significant cost savings.</p><p>From aerospace to electronics and beyond, advanced thermoplastics offer effective solutions to common challenges associated with traditional thermoplastic materials across various industries.</p><hr><p>You have just been reading an excerpt from Chapter 3 of The Engineering Thermoplastics Guide. Download the full guide below for the full text, including technical diagrams and application notes.&nbsp;</p><p><img src="https://images.wevolver.com/eyJidWNrZXQiOiJ3ZXZvbHZlci1wcm9qZWN0LWltYWdlcyIsImtleSI6ImZyb2FsYS8xNzA4MzUyMTY5MzYyLTMucG5nIiwiZWRpdHMiOnsicmVzaXplIjp7IndpZHRoIjo5NTAsImZpdCI6ImNvdmVyIn19fQ==" style="width: 300px;" class="fr-fic fr-dib"></p><p><span contenteditable="false" draggable="true" class="fr-video fr-deletable fr-fvc fr-dvb fr-draggable"><iframe width="540" height="700" src="https://c8056756.sibforms.com/serve/MUIFALhRx-pzB3WdCribJmgCdXRujbxbHx5nFTSwlI1hMI0Myb_EyFY_vhDjBDRPcymlHRNBCzvC-fQiSkGEQkoK8kgTHL3zmqclwy-WxYt1Os2RIjdQNPC5WmiKyhwzIXNwBHCep72gg8nmirJN2B4QVCiyglK7g-2fJEtOqlsvDmuRlSiVlE1F0VvwivibRK_weMJrZESJHGfe" frameborder="0" scrolling="auto" allowfullscreen="" style="display: block;margin-left: auto;margin-right: auto;max-width: 100%;" class="fr-draggable" data-lf-form-tracking-inspected-kn9eq4roawkarlvp="true" data-lf-yt-playback-inspected-kn9eq4roawkarlvp="true" data-lf-vimeo-playback-inspected-kn9eq4roawkarlvp="true"></iframe></span><br></p><h2>References</h2><p dir="ltr" id="isPasted">1. Gilbert M, editor. Brydson’s Plastics Materials. 8th ed. Oxford: Butterworth-Heinemann Elsevier; 2017.</p><p dir="ltr">9. Subramanian MN. Plastics Additives and Testing. Hoboken: Scrivener and John Wiley &amp; Sons; 2013.</p><p dir="ltr">10. Fink JK. A Concise Introduction to Additives for Thermoplastic Polymers. Hoboken: Scrivener and John Wiley &amp; Sons; 2010.</p>

To enhance the applicability of thermoplastics across various industries, reinforcing additives are added to improve properties such as mechanical strength, UV resistance, and conductivity, contributing to the material's overall performance.

Engineering Thermoplastics Guide. Chapter 3. Performance Enhancement Strategies for Engineering Plastics Products

<p>This is an excerpt from Chapter 2 of The Engineering Thermoplastics Guide. Download the full guide below for the full text, including technical diagrams and application notes.&nbsp;</p><p><img src="https://images.wevolver.com/eyJidWNrZXQiOiJ3ZXZvbHZlci1wcm9qZWN0LWltYWdlcyIsImtleSI6ImZyb2FsYS8xNzA3NDg3ODAxOTkxLTMucG5nIiwiZWRpdHMiOnsicmVzaXplIjp7IndpZHRoIjo5NTAsImZpdCI6ImNvdmVyIn19fQ==" style="width: 300px;" class="fr-fic fr-dib"></p><p><span contenteditable="false" draggable="true" class="fr-video fr-deletable fr-fvc fr-dvb fr-draggable"><iframe width="540" height="700" src="https://c8056756.sibforms.com/serve/MUIFALhRx-pzB3WdCribJmgCdXRujbxbHx5nFTSwlI1hMI0Myb_EyFY_vhDjBDRPcymlHRNBCzvC-fQiSkGEQkoK8kgTHL3zmqclwy-WxYt1Os2RIjdQNPC5WmiKyhwzIXNwBHCep72gg8nmirJN2B4QVCiyglK7g-2fJEtOqlsvDmuRlSiVlE1F0VvwivibRK_weMJrZESJHGfe" frameborder="0" scrolling="auto" allowfullscreen="" style="display: block;margin-left: auto;margin-right: auto;max-width: 100%;" class="fr-draggable" data-lf-form-tracking-inspected-kn9eq4roawkarlvp="true" data-lf-yt-playback-inspected-kn9eq4roawkarlvp="true" data-lf-vimeo-playback-inspected-kn9eq4roawkarlvp="true"><span class="fr-mk" style="display: none;">&nbsp;</span><span class="fr-mk" style="display: none;">&nbsp;</span></iframe></span></p><div data-testid="conversation-turn-7" id="isPasted"><div data-message-author-role="assistant" data-message-id="9d84dc13-7835-44f7-bc7f-c129488912ff"><h2 dir="ltr" id="isPasted">Introduction</h2><p dir="ltr">The widespread success of thermoplastic materials today is related to their easy processability. Compared to thermosets, which undergo irreversible curing processes, thermoplastics can be reversibly melted and hardened in any desired shape. In the post-war era, the worldwide use of thermoplastics surpassed that of thermosets in most applications due to increased production, low cost, and ease of manufacturing.</p><p dir="ltr">While conventional techniques, including subtractive manufacturing (machining), welding, and gluing can be applied to most thermoplastics, melt-processing offers advantages unique to thermoplastic materials. In melt-processing, granules or powder of plastics are heated to reduce the viscosity to allow easy shaping of the desired components. Melt-processing offers design freedom at very low costs and is one of the core reasons for the widespread success of thermoplastic materials. <sup>[1]</sup></p><p dir="ltr">In recent years, additive manufacturing has emerged as an increasingly powerful solution across various industries. Because of their characteristics, thermoplastics are the most suitable materials for 3D printing. However, developing additive manufacturing processes for engineering and advanced thermoplastics is still an open challenge.</p><p dir="ltr">The processability of thermoplastics depends on the specific properties of each material. While for most commodity plastics the manufacturing is straightforward, in the case of engineering and advanced thermoplastics there are unique challenges to keep in mind. Material waste needs to be minimized, and consistent quality and performance must be ensured for demanding engineering applications.</p><p dir="ltr">In this chapter except you will learn about the most significant challenges in engineering thermoplastic processing. The main processing methods of thermoplastics and their applications will be discussed. Download the full report for images, graphs and case studies.&nbsp;</p><h2 dir="ltr">Challenges of Processing Engineering Thermoplastics</h2><p dir="ltr">Thermoplastics offer several advantages, including easy processing with low energy consumption, low density, and aesthetic appeal. However, achieving quality plastic products can be challenging, especially when high-performance standards are required. To address this, a careful design process is crucial, starting with the selection of the most suitable processing method for your thermoplastic of choice.</p><p dir="ltr">Manufacturing thermoplastic components demands precise control of temperature, pressure, and cooling rates due to narrow processing windows, which, if not followed, can lead to defects and product failure. Melt processing can lead to anisotropy in the finished products, resulting in directionally dependent physical properties in the material., Thiswhich can determineresult in inconsistent mechanical properties in the final component. When substituting metal with engineering or advanced thermoplastics, you should keep in mind that different materials pose unique design challenges.</p><p dir="ltr">Many engineering and advanced thermoplastics, such as PC, PEI, and PA, are moisture-sensitive, necessitating careful drying prior to melt-processing to prevent material degradation and maintain product performance. Moisture can adversely affect the plastics' properties leading to bubbles, imperfections, or reduced mechanical properties.</p><p dir="ltr">Additionally, advanced thermoplastics require exceptionally high processing temperatures, often surpassing 300 °C. This requires specialized heating elements, insulation, and cooling procedures. High energy expenditure and increased safety precautions should also be considered. <sup>[5]</sup></p></div></div><p dir="ltr" id="isPasted">Injection molding is a melt-processing approach where thermoplastic material is heated and subjected to pressure, filling the interior of a mold. Afterward, the thermoplastics cool and regain rigidity, completing the molding cycle. After demolding the cycle can start from new. An injection-molding machine consists of an extruder for plasticizing the resin, a ram system for high-pressure material introduction into the mold, and a cooling device to facilitate part solidification. Key variables in the injection molding process include cylinder temperature, mold temperature, injection rate, holding pressure, back pressure, and the speed of the screw's rotation.<sup>[6]</sup></p><p dir="ltr">One of the key challenges of injection molding is that, due to differences in densities between the solid polymer and the melt, cooling results in dimensional shrinkage. In the case of some semi-crystalline polymers, this contraction can reach 20% of the original volume.</p><p dir="ltr">The inherent shrinkage can be compensated for by injecting additional material in a step known as the holding phase. However, a residual contraction between 0.5% and 2.5% is unavoidable with injection molding, and should always be kept into account when designing the molds.<sup>[1]</sup></p><h2 dir="ltr" id="isPasted">Additive Manufacturing of Engineering Thermoplastics</h2><p dir="ltr">Additive manufacturing of thermoplastics, also known as 3D printing, offers an alternative approach to creating complex parts rapidly, layer by layer, without the need for traditional tool and mold fabrication and with maximum design freedom. This technology has revolutionized the production of prototypes and products, resulting in substantial cost and time savings since its invention in 1986.</p><p dir="ltr">Due to their ability to melt and solidify into any desired shape, thermoplastics are the ideal materials for additive manufacturing and have been the first materials used for this technology. Among the different 3D printing processes utilized today for thermoplastics, most can be classified into two categories.</p><p dir="ltr">1. &nbsp; &nbsp;Extrusion 3D printing (E3DP). In E3DP, the material is heated to reduce its viscosity and extruded through the printer’s nozzle. For small-scale printers, the preferred approach is fused filament fabrication or FFF. Small-scale FFF printers extrude thermoplastic polymer filaments through a heated nozzle onto a heated bed, allowing for fast and cost-effective component production. However, these printers have limitations, including filament diameter constraints and smaller print areas. To address these challenges, large-scale extrusion printers for Big Area Additive Manufacturing or BAAM have been developed. These technologies implement more efficient feed systems and allow for faster production rates.</p><p dir="ltr">2. &nbsp; &nbsp;Powder Bed Fusion (PBF). In PBF, the powdered material is locally melted with a high-energy laser beam. Subsequent deposition and fusion of powder layers result in the gradual formation of the finished product. This process is suitable for large-scale industrial printing and can be used with engineering and advanced thermoplastics with higher melting temperatures.</p><p dir="ltr">For FFF, commodity plastics such as PETG and HDPE are a common choice. However, also engineering plastics such as polyamides and polycarbonates can be used with most professional extrusion 3D printers.</p><p dir="ltr">The technology for 3D printing with advanced thermoplastics is still in its infancy. Materials such as PEEK and PEI are challenging to extrude but can be used with PBF technology. New thermoplastic blends, composed of a mixture of advanced and standard thermoplastics, are also emerging as a suitable choice for additive manufacturing. <sup>[8]</sup></p><h2 dir="ltr">Selecting the Right Processing Method</h2><p dir="ltr">The choice of processing method for thermoplastics depends on the specific requirements of the desired application. Injection molding stands out as an excellent choice for mass production of standard thermoplastics due to its automation capabilities, cost efficiency, and superior surface finish. However, challenges such as part warpage and shrinkage should be carefully considered.</p><p dir="ltr">Extrusion processes are ideal for producing parts with constant cross-sections, making them suitable for products like pipes and window profiles. While versatile and capable of high output, they have limitations when it comes to incorporating reinforcements and can result in anisotropic properties.</p><p dir="ltr">Compression molding is particularly well-suited for engineering and advanced thermoplastics with high melting temperatures, offering advantages like minimal material waste and the ability to maintain product performance. This method is especially valuable for producing high-performance engineering components.&nbsp;<iframe id="6586facfec4e90822301b872" width="250" class="specs-iframe" height="440" src="https://wevolver.com/iframe/specs/meditech-implantable-polymers?iframe=true" frameborder="0" scrolling="no" data-lf-form-tracking-inspected-kn9eq4roawkarlvp="true" data-lf-yt-playback-inspected-kn9eq4roawkarlvp="true" data-lf-vimeo-playback-inspected-kn9eq4roawkarlvp="true"></iframe></p><p dir="ltr">Additionally, additive manufacturing, or 3D printing, has revolutionized rapid prototyping and product development. It is a valuable option for complex, customized parts, with extrusion 3D printing (E3DP) suitable for small-scale applications and Powder Bed Fusion (PBF) better suited for large-scale industrial printing, especially with engineering and advanced thermoplastics like PEEK and PEI.</p><p dir="ltr">Ultimately, the selection of the most suitable processing method should be based on factors such as material properties, production volume, design complexity, and cost considerations, ensuring that the chosen method aligns with the specific needs of each application.</p><p id="isPasted">You have just been reading an excerpt from Chapter 2 of The Engineering Thermoplastics Guide. Download the full guide below for the full text, including technical diagrams and application notes.&nbsp;</p><p><img src="https://images.wevolver.com/eyJidWNrZXQiOiJ3ZXZvbHZlci1wcm9qZWN0LWltYWdlcyIsImtleSI6ImZyb2FsYS8xNzA3NDg4NTA3MzQ3LTMucG5nIiwiZWRpdHMiOnsicmVzaXplIjp7IndpZHRoIjo5NTAsImZpdCI6ImNvdmVyIn19fQ==" style="width: 300px;" class="fr-fic fr-dib"></p><p><span contenteditable="false" draggable="true" class="fr-video fr-deletable fr-fvc fr-dvb fr-draggable"><iframe width="540" height="700" src="https://c8056756.sibforms.com/serve/MUIFALhRx-pzB3WdCribJmgCdXRujbxbHx5nFTSwlI1hMI0Myb_EyFY_vhDjBDRPcymlHRNBCzvC-fQiSkGEQkoK8kgTHL3zmqclwy-WxYt1Os2RIjdQNPC5WmiKyhwzIXNwBHCep72gg8nmirJN2B4QVCiyglK7g-2fJEtOqlsvDmuRlSiVlE1F0VvwivibRK_weMJrZESJHGfe" frameborder="0" scrolling="auto" allowfullscreen="" style="display: block;margin-left: auto;margin-right: auto;max-width: 100%;" class="fr-draggable" data-lf-form-tracking-inspected-kn9eq4roawkarlvp="true" data-lf-yt-playback-inspected-kn9eq4roawkarlvp="true" data-lf-vimeo-playback-inspected-kn9eq4roawkarlvp="true"></iframe></span><br></p><p dir="ltr"><br></p>

This chapter excerpt discusses thermoplastic processing in engineering, highlighting challenges like precise parameter control and moisture sensitivity while emphasizing methods like injection molding, extrusion, and additive manufacturing for shaping thermoplastics to meet diverse needs.

Engineering Thermoplastics Guide. Chapter 2. Processing Techniques of Engineering Thermoplastics

<p id="isPasted">Designing excellent <a href="https://www.protolabs.com/en-gb/services/injection-moulding/?utm_source=wevolver&utm_medium=referral&utm_campaign=uk-design-tip-0224&utm_content=wevolver-resin-flow-dt-0224" title="Injection Moulding" target="_blank" id="isPasted">injection-moulded</a> parts is dependent on many factors. Proper flow of the resin into the mould is one of them. We digitally simulate resin flow through your part geometry during our <a href="https://www.protolabs.com/en-gb/automated-design-analysis/?utm_source=wevolver&utm_medium=referral&utm_campaign=uk-design-tip-0224&utm_content=wevolver-resin-flow-dt-0224" title="Automated Design Analysis" target="_blank">DFM (Design for Manufacturability) analysis</a>. The resulting data that emerges will essentially help you design a part that will mould better.</p><p>Resin flow analysis is automatically applied to a small percentage of parts where mouldability issues are immediately present, but flow analysis is also available upon request. Better yet, it’s free, all to help you design better parts and help us get them to you as fast as possible.</p><p><img width="570" src="https://images.wevolver.com/eyJidWNrZXQiOiJ3ZXZvbHZlci1wcm9qZWN0LWltYWdlcyIsImtleSI6ImZyb2FsYS8xNzA3MjMxNDEwMDU3LTE3MDcyMzE0MTAwNTcucG5nIiwiZWRpdHMiOnsicmVzaXplIjp7IndpZHRoIjo5NTAsImZpdCI6ImNvdmVyIn19fQ==" align="left" alt="Resin flow analysis illustration" class="fr-fil fr-dii"></p><p><em>Figure 1: Flow analysis helps determine gate placement, locate knit lines and identify areas where gas trappings can occur. If needed, Application Engineers (AEs) can recommend design modifications to improve the mouldability of the part</em><a id="_anchor_1" href="#_msocom_1" language="JavaScript" name="_msoanchor_1" target="_blank"></a>.</p><p>&nbsp;</p><p>How does resin flow analysis help?</p><ul><li>It aids in the positioning of the gate or gates on your part.</li><li>It shows the position of knit lines allowing you to improve the cosmetic and physical properties of your part (Figure 1).</li><li>It locates trouble spots that are hard to fill within the part.</li><li>It tells you whether or not we can fill your part with a selected material.</li></ul><p>&nbsp;</p><p><img width="570" src="https://images.wevolver.com/eyJidWNrZXQiOiJ3ZXZvbHZlci1wcm9qZWN0LWltYWdlcyIsImtleSI6ImZyb2FsYS8xNzA3MjMxNDEwMDY1LTE3MDcyMzE0MTAwNjUucG5nIiwiZWRpdHMiOnsicmVzaXplIjp7IndpZHRoIjo5NTAsImZpdCI6ImNvdmVyIn19fQ==" align="left" alt="Colour coding of flow analysis" class="fr-fil fr-dii"></p><p><em>Figure 2: The colour coding gets “hotter” as the pressure increases. Gold, yellow and red represent high pressure and reduced flow. Blue and green colours mean flow is good, and the part will have a wide process window to work with.</em></p><p>The analysis also examines how resins flow with specific temperatures and injection pressures (Figure 2). As the <a href="https://www.protolabs.com/en-gb/materials/comparison-guide/?category=plastic:rubber&process=injectionmolding&utm_source=wevolver&utm_medium=referral&utm_campaign=uk-design-tip-0224&utm_content=wevolver-resin-flow-dt-0224" target="_blank">material</a> cools, it begins to harden, so gate pressure increases. The higher the pressure, the more complex the fill, which creates more significant concern about weak knit lines (contributing to poor part integrity), flash, sink, and shorts.</p><p>Plastics with good flow characteristics include polypropylene, K-Resin, HDPE, LDPE and unfilled nylons. Resins such as PC and ABS/polycarbonate tend to flow poorly.</p><p>Resin flow analysis works to pinpoint issues that can arise from these difficult flowing materials as well as other issues like thin walls and complicated geometries, providing solutions to improve flow and mouldability. Our design analysis, however, does not show areas of distortions or sink in your part.</p><p>&nbsp;</p><p><img border="0" width="570" src="https://images.wevolver.com/eyJidWNrZXQiOiJ3ZXZvbHZlci1wcm9qZWN0LWltYWdlcyIsImtleSI6ImZyb2FsYS8xNzA3MjMxNDEwMDcyLTE3MDcyMzE0MTAwNzIuanBlZyIsImVkaXRzIjp7InJlc2l6ZSI6eyJ3aWR0aCI6OTUwLCJmaXQiOiJjb3ZlciJ9fX0=" alt="Finished injection-moulded part" class="fr-fic fr-dii"></p><p><em>Figure 3: With the help of resin flow analysis, slight modifications such as increasing wall thickness can be made to your CAD model to create better flow and, ultimately, better parts.</em></p><p>If a material is not listed, our Application Engineers (AEs) will run an initial flow analysis with our default material, Makrolon 2458 (PC). Since it’s a difficult resin, a successful run-through resin flow analysis often means that any other resins you select will also work.</p><p>What if your part is not filling right? An AE can provide solutions such as increasing the wall thickness of the part, adding multiple gates or different material options (Figure 3). Remember that if you see Makrolon 2458 listed as the material and it’s not what you intend to use, AEs can correct it and run another simulation.</p><p>For additional resources such as moulding and prototyping processes, resin options, video tutorials, and more, check out <a href="https://www.protolabs.com/en-gb/?utm_source=wevolver&utm_medium=referral&utm_campaign=uk-design-tip-0224&utm_content=wevolver-resin-flow-dt-0224" title="United Kingdom" target="_blank">protolabs.com/en-gb/</a>.</p><p>As always, feel free to contact an applications engineer with any questions, at <a href="mailto:applicationengineers@protolabs.co.uk" target="_blank">applicationengineers@protolabs.co.uk</a> or contact our customer service department at <a href="mailto:customerservice@protolabs.co.uk" target="_blank">customerservice@protolabs.co.uk</a></p><div id="_com_3" language="JavaScript"><br></div>

Use thermoplastic resin flow analysis to improve the mouldability of your parts.

When in Doubt, Go With the Flow - Proper Resin Flow

<p dir="ltr">This is an excerpt from Chapter 1 of The Engineering Thermoplastics Guide. Download the full guide below for the full text, including technical diagrams and application notes.&nbsp;</p><p dir="ltr"><img src="https://images.wevolver.com/eyJidWNrZXQiOiJ3ZXZvbHZlci1wcm9qZWN0LWltYWdlcyIsImtleSI6ImZyb2FsYS8xNzA3MTI0MjgxOTkxLTMucG5nIiwiZWRpdHMiOnsicmVzaXplIjp7IndpZHRoIjo5NTAsImZpdCI6ImNvdmVyIn19fQ==" style="width: 300px;" class="fr-fic fr-dib"></p><p dir="ltr"><span contenteditable="false" draggable="true" class="fr-video fr-deletable fr-fvc fr-dvb fr-draggable"><iframe width="540" height="700" src="https://c8056756.sibforms.com/serve/MUIFALhRx-pzB3WdCribJmgCdXRujbxbHx5nFTSwlI1hMI0Myb_EyFY_vhDjBDRPcymlHRNBCzvC-fQiSkGEQkoK8kgTHL3zmqclwy-WxYt1Os2RIjdQNPC5WmiKyhwzIXNwBHCep72gg8nmirJN2B4QVCiyglK7g-2fJEtOqlsvDmuRlSiVlE1F0VvwivibRK_weMJrZESJHGfe" frameborder="0" scrolling="auto" allowfullscreen="" style="display: block;margin-left: auto;margin-right: auto;max-width: 100%;" class="fr-draggable" data-lf-form-tracking-inspected-kn9eq4roawkarlvp="true" data-lf-yt-playback-inspected-kn9eq4roawkarlvp="true" data-lf-vimeo-playback-inspected-kn9eq4roawkarlvp="true"><span class="fr-mk" style="display: none;">&nbsp;</span><span class="fr-mk" style="display: none;">&nbsp;</span><span class="fr-mk" style="display: none;">&nbsp;</span><span class="fr-mk" style="display: none;">&nbsp;</span><span class="fr-mk" style="display: none;">&nbsp;</span></iframe></span></p><h2 dir="ltr" id="isPasted">Introduction&nbsp;</h2><p dir="ltr">Plastic products are ubiquitous in our lives. Total plastics production is estimated to be over 50 Mtons in Europe alone, and almost 300 Mtons in the entire world. [1]</p><p dir="ltr">Based on their functional characteristics and uses, thermoplastic materials can be sorted into three main categories:</p><p dir="ltr">· &nbsp; Standard or commodity thermoplastics, such as HDPE and PP. They are relatively low-cost, high-volume consumption materials, mainly used for packaging and consumer goods. They constitute the largest portion of thermoplastic materials produced today, with a global consumption of about 30 times that of engineering plastics and 600 times that of the advanced plastics group.</p><p dir="ltr">· &nbsp; General-purpose engineering thermoplastics, such as PC and PA. These materials generally exhibit higher thermal and mechanical resistance compared to commodity plastics. They are used as durable components in a large number of engineering applications.</p><p dir="ltr">· &nbsp; Advanced thermoplastics, such as PEEK and PPS. These materials are suitable for applications under extreme thermal, mechanical, and chemical conditions, where they can substitute thermosets and metals. They can typically withstand temperatures of over 200 °C and possess high strength, stiffness, and toughness.</p><p dir="ltr"><img src="https://images.wevolver.com/eyJidWNrZXQiOiJ3ZXZvbHZlci1wcm9qZWN0LWltYWdlcyIsImtleSI6ImZyb2FsYS8xNzA3MTI0ODMwMjQ3LUlNQUdFUy0wMSAoMikuanBnIiwiZWRpdHMiOnsicmVzaXplIjp7IndpZHRoIjo5NTAsImZpdCI6ImNvdmVyIn19fQ==" style="width: 300px;" class="fr-fic fr-dib"></p><h2 dir="ltr" id="isPasted">General Properties of Engineering Thermoplastics</h2><h3 dir="ltr">&nbsp;Chain flexibility and mobility</h3><p dir="ltr">In plastics, chemical microstructure is strongly tied to the material’s macroscopic properties. The structure-property relationship of thermoplastics is complex, but generally speaking, it boils down to chain flexibility, i.e. the freedom of movement of the atoms inside each polymer chain, and chain mobility, i.e. the freedom of movement of polymer chains with respect to each other.</p><p dir="ltr">Intrinsic chain flexibility is related to the energy required by molecules to rotate around chemical bonds. This, in turn, depends on the chemical structure of each polymer. If the polymer chain is linear and composed of mostly single aliphatic bonds, such as in the case of polyethylene (PE), polymer chains will be flexible. On the other hand, if the molecular structure contains aromatic groups, such as in the case of polycarbonates (PC) or polyether ketones (PEEK), the polymer chains will be more rigid.&nbsp;</p><p dir="ltr">Chain mobility between polymer chains is affected by molecular weight and chemical composition. If the molecules have high molecular weight or contain highly polar chemical groups capable of forming hydrogen bonds, chain mobility will be restricted.</p><h3 dir="ltr">Glass transition temperature and heat deflection temperature</h3><p dir="ltr">The differences in chain flexibility and mobility are mirrored in the macroscopic properties of thermoplastics.[1] Glass transition temperature, or Tg, is defined as the temperature below which a plastic material behaves as a glassy solid. Smaller flexibility and mobility of the polymer chains lead to higher Tg. All engineering and advanced thermoplastics are high-Tg materials. This makes them more suitable for demanding applications due to their higher thermal and mechanical resistance.</p><p dir="ltr">In engineering, another significant parameter to understand the thermal properties of thermoplastics is heat deflection temperature or HDT. This parameter is a measure of the effect of temperature on the resistance to distortion of the thermoplastic under load. In other words, if a thermoplastic material has a high HDT, it is more likely to preserve its shape and mechanical properties even at high temperatures.</p><h3 dir="ltr" id="isPasted">Crystallinity</h3><p dir="ltr">Thermoplastics are classified as either semi-crystalline or amorphous. Put simply, crystallinity is a measure of the degree of order in the arrangement of the polymer chains. While amorphous thermoplastics have a random molecular arrangement, semi-crystalline thermoplastics possess a regular molecular structure.[1]</p><p dir="ltr">This has significant consequences on the functional properties of plastic products. Semi-crystalline thermoplastics, such as polyethylene terephthalate (PET) or PEEK, typically possess higher mechanical strength and stiffness compared to amorphous materials. They also tend to exhibit better chemical resistance.</p><p dir="ltr">Conversely, amorphous thermoplastics, such as polysulfone (PSU) or polyetherimide (PEI), are flexible and possess higher impact resistance. Because they tend to be transparent, they are also employed for optical applications.</p><h2 dir="ltr">Classification of Thermoplastic Products</h2><h3 dir="ltr">Advanced Engineering Plastics</h3><p dir="ltr">Advanced engineering plastics possess high mechanical strength and stiffness even at extreme temperatures, between 120 °C and 230 °C. Some advanced thermoplastics can now be used at temperatures surpassing 400 °C. These materials also tend to possess broad chemical stability and excellent electrical properties. They are suitable for the most challenging and demanding applications.</p><h3 dir="ltr">Imidized polymers (PEI, PAI, PI)</h3><p dir="ltr">The family of imidized polymers is characterized by the presence of at least one imide chemical bond (CO-N-CO). This group includes thermoplastic imides (PI), polyamide-imides (PAI),polyetherimides (PEI), and polybenzimidazole (PBI).</p><p dir="ltr" id="isPasted">Pure polyimide (PI) can withstand temperatures up to 360 °C, which makes it suitable for demanding applications as a lightweight alternative to metal. It offers high strength, toughness, and chemical resistance. However, its high Tg means it is not easily melt processable. [1]</p><p dir="ltr">PEI was first developed to overcome this processability issue. This amorphous thermoplastic with high HDT, high tensile strength, and modulus ensures a reliable performance at high temperatures. Additionally, PEI’s electric properties remain stable over a wide range of frequencies. It can undergo repeated autoclave treatments. It is also flame-retardant and is resistant to hydrocarbons, alcohols, and acids. [2]</p><p dir="ltr">PAI’s flexible amide bond makes processability easier while retaining the outstanding thermal and chemical resistance properties of PI. This, combined with its optimal dielectric properties, makes it one of the most suitable materials for demanding applications in electronics.</p><p dir="ltr">All imidized polymers are hygroscopic, meaning they tend to absorb moisture. Therefore, parts must be carefully dried before use to prevent damage and ensure optimal performance. [3]</p><h4 dir="ltr">Sulfone polymers (PSU)</h4><p dir="ltr">Polysulfone (PSU) is an amorphous translucent thermoplastic. Chemically, it is characterized by diphenyl sulfone units.</p><h3 dir="ltr" id="isPasted">Structure of PSU</h3><p dir="ltr">Its chemical structure offers excellent stability, resulting in a broad temperature range, excellent mechanical properties, and good short-term chemical resistance to solvents and weak acids. It is lightweight and relatively inexpensive. It possesses good dimensional stability and generally is resistant to beta, gamma, and X-ray radiation. [1]</p><h4 dir="ltr">Polyphenylene sulfide (PPS)</h4><p dir="ltr">Polyphenylene sulfide (PPS) possesses a regular, semicrystalline structure.</p><p dir="ltr" id="isPasted">It exhibits the lowest moisture absorption of all advanced thermoplastics and is inherently flame-retardant. It possesses outstanding chemical resistance to both corrosive substances and solvents even at high temperatures. The low coefficient of thermal expansion provides optimal dimensional stability. Its mechanical properties depend on the degree of crystallinity: although the material has a high E-modulus, highly crystalline PPS can be relatively brittle. [1]</p><h4 dir="ltr">Polyether ether ketone (PEEK)</h4><p dir="ltr">PEEK is a semi-crystalline thermoplastic with outstanding thermal and mechanical properties. Similarly to other advanced thermoplastics, it owes its properties to its peculiar chemical structure, containing phenyl and ketone groups which offer high stability and rigidity.</p><p dir="ltr" id="isPasted">PEEK possesses a high E-modulus and tensile strength. It melts at 350°C and is resistant to high temperatures. Its chemical resistance to organic solvents is also outstanding, and it is not hydrolyzed by either water or high-pressure steam. Very good resistance to radiation is another feature of this advanced plastic material. [1]</p><h4 dir="ltr">Polybenzimidazole (PBI)</h4><p dir="ltr">Polybenzimidazole (PBI) is an amorphous thermoplastic. It can be classified as an extreme thermoplastic material, exhibiting the highest thermal stability of all advanced thermoplastics. It can withstand temperatures as high as 430°C for prolonged periods, and above 500 °C for up to a few hours.</p><p dir="ltr" id="isPasted">Above 200°C, high molar mass PBI possesses the highest mechanical properties than any other unfilled plastic material. It does not burn and preserves its mechanical characteristics even when charred. Because of this, it is one of the most outstanding advanced thermoplastic products available on the market. [1]</p><h4 dir="ltr">Fluoropolymers (PTFE)</h4><p dir="ltr">Fluoropolymers, such as PTFE, are characterized by the presence of highly stable carbon-fluorine chemical bonds.</p><p dir="ltr" id="isPasted">This chemical stability, coupled with high crystallinity, makes PTFE especially heat-resistant, even at high temperatures. Fluoropolymers possess outstanding chemical stability and are resistant to most solvents and corrosive chemicals. They possess excellent strength and stiffness. Excellent dielectric properties and inherently low friction behavior are also key advantages of these materials. [1]</p><h4 dir="ltr">General Engineering Plastics</h4><p dir="ltr">Engineering thermoplastics ensure consistent mechanical properties between &nbsp;5 °C and 120 °C. They can be used to replace heavier and less reliable materials, such as bronze or rubber. [2] Good chemical stability, non-toxicity, and good electrical properties are additional advantages of many engineering thermoplastics.&nbsp;</p><h4 dir="ltr">Polyamides (PA6, PA66, PA46)</h4><p dir="ltr">Aliphatic polyamides, also known as nylons, are semi-crystalline thermoplastic materials. They are characterized by the amide group CONH.</p><p dir="ltr" id="isPasted">Different kinds of polyamides are labeled based on the monomers used to manufacture them. The most widely used polyamides are PA6 and PA66, commonly used in packaging and textiles. They both possess good stiffness and strength at high temperatures, good wear resistance, and good impact strength at low temperatures. They are resistant to non-polar solvents and alkalis.</p><p dir="ltr">Due to its superior mechanical performance, PA46 is considered more suitable for engineering applications. Up to 200°C, it retains outstanding strength and stiffness. Additionally, it provides low friction combined with optimal wear resistance. Good electrical insulation and radiation resistance are additional benefits of this engineering thermoplastic. [4]</p><p dir="ltr">Water absorption of all polyamides is very high. Low moisture should be maintained during processing to prevent the loss of mechanical properties.</p><h4 dir="ltr">Polycarbonates (PC)</h4><p dir="ltr">Polycarbonates (PCs) are a family of engineering thermoplastics characterized by carbonate (OCOO) bonds.</p><p dir="ltr" id="isPasted">PCs possess superior impact strength and elasticity, minimal moisture absorption, excellent resistance to acids, and remarkable electrical insulation properties. This makes PC a valuable choice for demanding applications in the electronics industry. This class of thermoplastics exhibits toughness and rigidity up to 130 °C.</p><p dir="ltr">However, these materials are often sensitive to UV. Balancing crystallinity is crucial to maintaining optimal mechanical properties in PCs. [2]</p><h4 dir="ltr">Polyethylene terephthalate (PET)</h4><p dir="ltr">Despite being well-known for packaging applications, Polyethylene terephthalate (PET) is also a versatile engineering thermoplastic.&nbsp;</p><h2 dir="ltr" id="isPasted">Structure of PET</h2><p dir="ltr">This thermoplastic possesses exceptional dimensional stability and wear resistance. With its low coefficient of friction, high strength, and resistance to moderately acidic solutions, it is suitable for many engineering applications. [1]</p><p dir="ltr">While PET is readily available and cost-effective, it has limitations, including relatively low heat resistance and susceptibility to oxidation. However, its high strength-to-weight ratio, optical properties, toughness, and recyclability make it a desirable choice in many contexts.</p><h4 dir="ltr">Polyacetals (POM-C, POM-H)</h4><p dir="ltr">Polyacetals, also known as polyoxymethylenes (POMs), are engineering thermoplastics derived from the polymerization of formaldehyde. They are commercially available in both homopolymer (POM-H) and copolymer (POM-C) forms.</p><p dir="ltr" id="isPasted">These materials offer improved dimensional stability but slightly lower wear resistance compared to polyamides. Acetals are characterized by high mechanical strength, stiffness, hardness, resilience, resistance to creep, and excellent impact strength at low temperatures. [2] They also exhibit low water absorption for outstanding dimensional stability. However, polyamides outperform acetals in impact toughness and abrasion resistance. [1]</p><p dir="ltr">Acetal homopolymer resins are particularly resistant to organic solvents, especially at low temperatures. POM-C is highly resistant to strong alkalis. However, polyacetals should be avoided in strong acids or oxidizing environments. Water does not significantly degrade the polymer but may cause minimal swelling (0.8%) or permeation under certain conditions.</p><h3 dir="ltr">Standard Plastics</h3><p dir="ltr">Standard plastics are the most common thermoplastics used in consumer applications and packaging. They are inexpensive and ensure good chemical and mechanical properties below 65 °C.</p><h4 dir="ltr" id="isPasted">Polyethylene (LDPE, HDPE, HMW-PE, UHMW-PE)</h4><p dir="ltr">Polyethylene (PE) is the most widely used thermoplastic. It is an inexpensive material with an excellent balance of properties. In general, it offers ease of processing, toughness, and flexibility. Excellent electrical insulation across various frequencies, strong chemical resistance, and transparency make it suitable for several commodity applications.</p><p dir="ltr">In particular, molecular branching and molecular weight influence the characteristics of this thermoplastic. [1] As a result, there are numerous grades of PE with varying properties.</p><p dir="ltr">High-Density Polyethylene (HDPE) is characterized by remarkable impact resistance, tensile strength, chemical resistance, and low moisture absorption. Low-density polyethylene (LDPE) is flexible, with great impact and chemical resistance. High and Ultra-High Molecular Weight Polyethylenes (UHMW-PE) are highly versatile materials offering superb wear resistance properties, making them ideal for demanding applications like prosthetics.</p><h4 dir="ltr">Polypropylene (PP)</h4><p dir="ltr">Polypropylene (PP) is a linear hydrocarbon thermoplastic with notable similarities to PE. PP's electrical characteristics closely resemble those of HDPE, making it an excellent insulating material, particularly for capacitor films. Its chemical resistance aligns with HDPE as well, as both polymers are highly resistant to most solvents and corrosive chemicals. [1]</p><p dir="ltr">Additionally, PP offers excellent resistance to stress cracking, ease of fabrication and welding, a high strength-to-weight ratio, minimal moisture absorption, and minimal porosity. These properties make PP a versatile choice for various applications, from electrical insulation to chemical-resistant components.</p><p dir="ltr">Download the full report for the rest of the chapter, which includes details on &nbsp;application of advanced thermoplastics.&nbsp;</p><p dir="ltr"><img src="https://images.wevolver.com/eyJidWNrZXQiOiJ3ZXZvbHZlci1wcm9qZWN0LWltYWdlcyIsImtleSI6ImZyb2FsYS8xNzA3MTI1NzQxMzI4LTMucG5nIiwiZWRpdHMiOnsicmVzaXplIjp7IndpZHRoIjo5NTAsImZpdCI6ImNvdmVyIn19fQ==" style="width: 300px;" class="fr-fic fr-dib"></p><p dir="ltr"><span contenteditable="false" draggable="true" class="fr-video fr-deletable fr-fvc fr-dvb fr-draggable"><iframe width="540" height="700" src="https://c8056756.sibforms.com/serve/MUIFALhRx-pzB3WdCribJmgCdXRujbxbHx5nFTSwlI1hMI0Myb_EyFY_vhDjBDRPcymlHRNBCzvC-fQiSkGEQkoK8kgTHL3zmqclwy-WxYt1Os2RIjdQNPC5WmiKyhwzIXNwBHCep72gg8nmirJN2B4QVCiyglK7g-2fJEtOqlsvDmuRlSiVlE1F0VvwivibRK_weMJrZESJHGfe" frameborder="0" scrolling="auto" allowfullscreen="" style="display: block;margin-left: auto;margin-right: auto;max-width: 100%;" class="fr-draggable" data-lf-form-tracking-inspected-kn9eq4roawkarlvp="true" data-lf-yt-playback-inspected-kn9eq4roawkarlvp="true" data-lf-vimeo-playback-inspected-kn9eq4roawkarlvp="true"><span class="fr-mk" style="display: none;">&nbsp;</span></iframe></span></p><h1 dir="ltr" id="isPasted">References</h1><p dir="ltr">[1] &nbsp; &nbsp;Gilbert M, editor. Brydson’s Plastics Materials. 8th ed. Oxford: Butterworth-Heinemann Elsevier; 2017.</p><p dir="ltr">[2] &nbsp; &nbsp;Margolis JM, editor. Engineering Plastics Handbook. 2006. New York: McGraw-Hill.</p><p dir="ltr">[3] &nbsp; &nbsp;Campbell RW. Down-to-earth role for imidized polymers. Machine Design [Internet]. February 7, 2002. Available from: https://www.machinedesign.com/archive/article/21813964/downtoearth-role-for-imidized-polymers</p><p>[4] &nbsp; &nbsp;Polyamide (PA) or Nylon: Complete Guide (PA6, PA66, PA11, PA12…). Omnexus [Internet]. September 27, 2023. Available from: https://omnexus.specialchem.com/selection-guide/polyamide-pa-nylon</p>

This chapter excerpt introduced an overview of the properties of different classes of thermoplastic materials, with special attention to engineering and advanced thermoplastics.


Engineering Thermoplastics Guide. Chapter 1: Properties and Classification of Engineering Plastic Products

<p><br></p><p>Thermoplastics are the most diverse and widely employed group of plastic materials used in a variety of applications, from consumer goods to the most advanced and challenging engineering applications. Different from thermosets, thermoplastics can be reversibly melted and solidified, making them easier to process and recycle.&nbsp;</p><p>This guide aims to offer a comprehensive perspective on thermoplastic materials. It will cover the different types and properties of thermoplastics, including engineering and advanced plastics used in demanding applications across various industries.</p><p>Download the full guide now.&nbsp;</p><p><img src="https://images.wevolver.com/eyJidWNrZXQiOiJ3ZXZvbHZlci1wcm9qZWN0LWltYWdlcyIsImtleSI6ImZyb2FsYS8xNzA2MDk0MzUwODY0LXVsdGltYWtlciB0aWxlICgzKS5wbmciLCJlZGl0cyI6eyJyZXNpemUiOnsid2lkdGgiOjk1MCwiZml0IjoiY292ZXIifX19" style="width: 300px;" class="fr-fic fr-dib"></p><p><br></p><h2>The Guide Overview</h2><p>The properties, classification, and applications of thermoplastics are thoroughly discussed in Chapter 1. In Chapter 2, you will also learn about the most widely used processing techniques of thermoplastic materials, from conventional manufacturing to 3D printing. Chapter 3 is focused on performance enhancement strategies of thermoplastics, such as reinforcements and additives for different functional properties.</p><p>Some of the latest cutting-edge developments in thermoplastics materials science, from advanced formulations to smart materials, are discussed in Chapter 4. A focus on thermoplastic composites is offered in Chapter 5, with a discussion of their general properties and classification, processing methods and engineering applications.&nbsp;</p><p>Finally, Chapter 6 is dedicated to the sustainability and environmental impact of thermoplastics, focusing on the importance of Life Cycle Assessment and the implementation of sustainable design principles along the entire value chain. This guide is accompanied by a discussion of relevant case studies from Mitsubishi Chemical Group’s portfolio, offering real-world examples of the countless applications, open challenges, and future outlooks for thermoplastic materials.</p><p><br></p>

<p>Thermoplastics are the most diverse and widely employed group of plastic materials used in a variety of applications, from consumer goods to the most advanced and challenging engineering applications. Different from thermosets, thermoplastics can be reversibly melted and solidified, making them easier to process and recycle.</p><p>This guide aims to offer a comprehensive perspective on thermoplastic materials. It will cover the different types and properties of thermoplastics, including engineering and advanced plastics used in demanding applications across various industries.</p><p><strong>Download the full guide now.&nbsp;</strong></p><h2><img src="https://images.wevolver.com/eyJidWNrZXQiOiJ3ZXZvbHZlci1wcm9qZWN0LWltYWdlcyIsImtleSI6ImZyb2FsYS8xNzA2MDk0MzUwODY0LXVsdGltYWtlciB0aWxlICgzKS5wbmciLCJlZGl0cyI6eyJyZXNpemUiOnsid2lkdGgiOjk1MCwiZml0IjoiY292ZXIifX19" style="width: 300px;" class="fr-fic fr-dib"><span contenteditable="false" draggable="true" class="fr-video fr-deletable fr-fvc fr-dvb fr-draggable"><iframe width="540" height="800" src="https://c8056756.sibforms.com/serve/MUIFABJ2dsEg-TzfuIHwkNaP8rrmV_SKFSVMlqyx1LM-mSTZhZ3hPqjJD598qbGxsnfmzAeqX7HR_z3WSCcscUYhZ12-nztEbe3T2257sY3X3CQfmq2Aek5yh_tUmHERus91XUMWAALhGdDnEwViXD_iz9jUK2febGjQempqigbxcfYVhbmY-ZKpnJrI8yeYqz_N83gwkl017FX-" frameborder="0" scrolling="auto" allowfullscreen="" style="display: block;margin-left: auto;margin-right: auto;max-width: 100%;" class="fr-draggable" data-lf-form-tracking-inspected-kn9eq4roawkarlvp="true" data-lf-yt-playback-inspected-kn9eq4roawkarlvp="true" data-lf-vimeo-playback-inspected-kn9eq4roawkarlvp="true"></iframe></span>The Guide Overview</h2><p>The properties, classification, and applications of thermoplastics are thoroughly discussed in Chapter 1. In Chapter 2, you will also learn about the most widely used processing techniques of thermoplastic materials, from conventional manufacturing to 3D printing. Chapter 3 is focused on performance enhancement strategies of thermoplastics, such as reinforcements and additives for different functional properties.</p><p>Some of the latest cutting-edge developments in thermoplastics materials science, from advanced formulations to smart materials, are discussed in Chapter 4. A focus on thermoplastic composites is offered in Chapter 5, with a discussion of their general properties and classification, processing methods and engineering applications.&nbsp;</p><p>Finally, Chapter 6 is dedicated to the sustainability and environmental impact of thermoplastics, focusing on the importance of Life Cycle Assessment and the implementation of sustainable design principles along the entire value chain. This guide is accompanied by a discussion of relevant case studies from Mitsubishi Chemical Group’s portfolio, offering real-world examples of the countless applications, open challenges, and future outlooks for thermoplastic materials.</p><p>The guide is valuable for any engineer or designer working with thermoplastics. It includes multiple informative diagrams and technical graphics to comprehensively understand these materials' impact and future.&nbsp;</p><p><em>This report was written by Laura Tripaldi, with contributions and editing by Wevolver staff and Mitsubishi Chemical Group engineers.&nbsp;</em></p>