High Performance Thermoplastic Selection - Polyether (PPE, PAEK, PEEK, PEKK) [Part 2C]

Hello and welcome to the Part 2C of our High Performance Thermoplastics selection blog series. Today we discuss Polyphenylene Ether (PPE) and PPE blends, their chemistry and production processes, their main properties, processing methods, and applications.

Overview - 6 major high performance thermoplastics families (“the magnificent six”) 

In this blog post series we discuss six major high performance thermoplastics families (“the magnificent six”) which are outlined in the following enumeration

1. Introduction to High Performance Polymers

2. Short profile of the "magnificent six" families:

-Part 2A: Polysulfides (Polyphenylene sulfide - PPS), Polysulfones (PSU, PESU, PPSU), and Polyarylates (PAR)

-Part 2B: Imide-Based Polymers (PEI, PAI, PESI, TPI, PI) and Polybenzimidazoles (PBI, PBI+PEEK, PBI+PEKK)

-Part 2C: Polyether (PPE, PAEK, PEEK, PEKK)

-Part 2D: Liquid Crystal Polymers (LCP) and High-performance Polyesters (Polycyclohexylene terephthalate - PCT)

-Part 2E: Semi- and Fully Aromatic Polyamides (PARA, PPA, Aramid)

-Part 2F: Polyhalogenolefins (PTFE, PCTFE, FEP, PVDF, ECTFE)

Polyphenylene Ether (PPE) and its Blends with Polystyrene (PS) and Polyamide (PA)

Polyphenylene ether (PPE), also known as polyphenylene oxide (PPO), is a high-performance thermoplastic polymer renowned for its excellent thermal, mechanical, and electrical properties. While pure PPE exhibits some processing challenges due to its high melt viscosity, blending it with polystyrene (PS) significantly improves its processability while retaining many of its desirable characteristics. These PPE/PS blends have become commercially significant engineering thermoplastics.   

Jack Welch's team at General Electric faced a challenge with Polyphenylene Oxide (PPO): its extremely high glass transition temperature (208°C) made it difficult to process without degrading the material (the methyl groups of PPE are expected to undergo autoxidation). An important key to future success was the research team around Dan Fox, Allan S. Hay, and E. M. Boldebuck, who found out the miscibility of PPO with PS first. To overcome this, they decided to blend PPO with polystyrene (PS). This clever solution allowed them to maintain many of PPO's desirable properties, lower the glass transition temperature,  while also making the material easier to process at lower temperatures and more cost-effective.

Chemistry and Production Process

1. Chemistry of Polyphenylene Ether (PPE)

The base polymer, PPE, is typically synthesized through an oxidative coupling polymerization of substituted phenols, most commonly 2,6-dimethylphenol (also known as 2,6-xylenol). This reaction is catalyzed by a copper-amine complex in the presence of oxygen. The general chemical structure of PPE can be represented as (Figure 1):

Figure 1: Chemical structure of the polymer Polyphenylene Ether (PPE) [1].

The ether linkages (-O-) in the polymer backbone, along with the aromatic rings and the methyl substituents, contribute to PPE's stiffness, thermal stability, and chemical resistance.

2. Production of PPE/PS Blends

The production of PPE/PS blends primarily involves melt blending the two polymers. This process is typically carried out in extruders or other intensive mixing equipment. The key steps include:

• Raw Material Preparation: PPE and PS resins are typically received in pellet form. They may be dried to remove any moisture before blending.
• Melt Blending: The PPE and PS pellets are fed into an extruder, where they are heated and mechanically mixed. The screw design and processing conditions (temperature, screw speed) are crucial for achieving a homogeneous blend. Compatibilizers, such as styrene-butadiene-styrene (SBS) or styrene-ethylene/butylene-styrene (SEBS) block copolymers, are often added to improve the compatibility between the relatively non-polar PS and the more polar PPE. These compatibilizers help to reduce interfacial tension and prevent phase separation, leading to enhanced mechanical properties.
• Pelletizing: The molten blend exiting the extruder is then cooled and cut into pellets, which are the final product form for subsequent processing by manufacturers.

The ratio of PPE to PS in the blend can be varied to tailor the properties of the final material to specific application requirements. Higher PPE content generally leads to better thermal and mechanical performance, while higher PS content improves processability and reduces cost (Figure 2).   

Figure 2: Changing the glass transition temperature of PPE by changing the ratio of PPE and PS [1].

Main Properties of PPE/PS Blends

PPE/PS blends exhibit a combination of properties derived from both constituent polymers, often enhanced by the presence of compatibilizers. 

Key properties include:

• Excellent Thermal Stability: PPE inherently possesses high glass transition temperatures (Tg ) and heat deflection temperatures (HDT). Blending with PS can reduce these values compared to pure PPE, however the blends still offer good high-temperature performance compared to many other engineering thermoplastics.   
• Figure 3 shows the DMA of PPE+PS blend in comparison to High Impact Polystyrene (HIPS) and Polycarbonate (PC). PS has a glass transition temperature of about 100°C and up to this temperature PPE+PS can match PC in thermal performance (PC drops sharply at Tg of 147°C). There is no sharp drop in modulus observed with PPE+PS. 

Figure 3: Dynamic Mechanical Analysis (DMA) of PPE+PS vs HIPS vs PC. 

• Good Mechanical Strength and Stiffness: PPE contributes to the blend's rigidity and strength. The impact strength can be tailored depending on the blend ratio and the use of impact modifiers.  
• Excellent Electrical Insulation Properties: PPE is an excellent electrical insulator with a low dielectric constant and high dielectric strength, which are largely retained in the blends.   
• Good Chemical Resistance: PPE offers good resistance to many chemicals, including acids, bases, and detergents. The chemical resistance of the blend is generally good but can be influenced by the PS content, which is more susceptible to certain solvents.   
• High Stability towards Hydrolysis: hydrolysis resistance of PPE is superior when compared to other engineering plastics such as PBT and PA.
• Improved Processability: The addition of PS significantly lowers the melt viscosity of PPE, making the blends easier to process using conventional methods like injection molding and extrusion.   
• Dimensional Stability: PPE contributes to low water absorption and excellent dimensional stability, which is important for applications requiring tight tolerances.   
• Flame Retardancy: PPE is inherently flame retardant. Blends often exhibit good flame retardant properties, especially when combined with flame retardant additives.   

Apart from blending PPE with PS; blends out of PPE with PA are possible too. PPE/PA blends have the following advantages: 

• Combines Key Strengths: Blends the excellent dimensional stability, low water absorption, and heat resistance of PPE with the superior chemical resistance and flow of PA.
• Enhanced Performance: The resulting material is exceptionally chemically resistant and boasts the stiffness, impact resistance, and heat performance needed for demanding applications like on-line painting.
• Significant Weight Savings: Unfilled PPE/PA blends can offer part-weight reductions of up to 25% compared to glass or mineral-filled resins, thanks to their low density.

Outperforming properties of PPE/PS blends:  

• Low specific gravity: 1.1 g/cm3. Most engineering polymers such as PC, PBT, and POM have a specific density of 1.2 g/cm3 and more. 
• High self-extinguishing property: PPE has a high oxygen index (27-29) and it is easy to add flame resistancy. 
• Excellent dielectric properties: PPE has a dielectric constant of 2.8 and a dielectric tangent of 6x1E-3. The dielectric breakdown strength (110 MV/m @ 0.5 mm thickness) is the highest among engineering plastics. 
• High dimensional accuracy: PPE has one of the lowest coefficient of linear thermal expansion among engineering polymers (5.8 x 10E-5 1/°C).

Processing Methods

PPE/PS blends can be processed using various thermoplastic processing techniques, including:

• Injection Moulding: This is the most common method for producing complex shaped parts from PPE/PS blends, leveraging their improved flow properties compared to pure PPE.
• Extrusion: These blends can be extruded into profiles, sheets, and films for various applications.  
• Blow Moulding: Certain grades of PPE/PS blends can be blow molded to produce hollow parts.
• Thermoforming: Sheets extruded from PPE/PS blends can be thermoformed into various shapes. 

Applications of PPE/PS Blends

The unique combination of properties makes PPE/PS blends suitable for a wide range of applications across various industries:

• Construction and Plumbing: Applications include pump housings, impellers, and other components requiring good mechanical and chemical resistance.
• Automotive Industry: Interior and exterior components such as instrument panels, door panels, wheel covers, and electrical connectors benefit from the blends' thermal stability, dimensional stability, and impact resistance.   
• Electrical and Electronics: Housings for electrical connectors, circuit breakers, switchgear, and other electrical components utilize the excellent electrical insulation properties and flame retardancy of PPE/PS blends.   
• Household Appliances: Components for washing machines, dishwashers, microwave ovens, and other appliances benefit from the blends' heat resistance, chemical resistance, and good mechanical properties.
• Business Equipment: Housings and internal components for computers, printers, and other office equipment utilize the blends' dimensional stability, electrical properties, and aesthetic appeal.   
• Healthcare: Certain grades of PPE/PS blends can be used in medical devices and equipment due to their sterilizability and chemical resistance.   

Trade Names

Several companies market PPE/PS blends under various trade names. Some well-known examples include:

• Noryl™: Formerly a trademark of GE Plastics, now owned by SABIC Innovative Plastics. This is one of the most widely recognized families of PPE-based resins, including various PPE/PS blends and other modifications.
• XYRON™ from Japanese chemical company Asahi Kasei.
• Various manufacturers such as Global Acetal (Lemalloy PPE) produce generic PPE/PS blends with specific property profiles.   

Economic Aspects

The market for PPE/PS blends is significant within the broader engineering thermoplastics market. The demand is driven by the increasing need for high-performance materials in automotive, electronics, plumbing and appliance industries.   

• Cost Factors: The cost of PPE/PS blends is influenced by the price of the base polymers (PPE and PS), the concentration of PPE in the blend, the type and amount of compatibilizers and additives used, and the manufacturing process. Generally, higher PPE content leads to higher costs.
• Market Trends: The trend towards lightweighting in the automotive industry and miniaturization in electronics continues to drive the demand for materials like PPE/PS blends that offer a balance of performance and processability. Growing environmental concerns are also pushing for more sustainable material solutions, which may influence the development of new PPE-based blends with recycled content or improved recyclability.
• Regional Variations: The demand and market dynamics for PPE/PS blends can vary across different geographical regions based on industrial activity and specific application needs.

In conclusion, polyphenylene ether (PPE) and its blends with polystyrene and polyamide represent a versatile class of engineering thermoplastics offering a compelling combination of high-performance properties and improved processability. Their wide range of applications across various industries underscores their economic and technological significance in the world of polymer engineering. As a polymer engineering student, understanding the nuances of these materials will undoubtedly be valuable in your future endeavors.   

In the upcoming Part 2C we will continue to discuss the Polyether high performance polymers such as PAEK, PEEK, and PEKK.

Thanks for reading & #findoutaboutplastics

Greetings, 

Herwig Juster

🔎I review your polymer material selection and plastic part design - contact me here

🔥 There is a problem keeping you awake - My personal website for Polymer Consulting

📊 Discover your Polymer Material Selection score by taking quick test here

Literature: 

[1] Allan S. Hay: Polymerization by Oxidative Coupling: Discovery and Commercialization of PPO and Noryl Resins

[2] https://www.sabic.com/en/products/specialties/noryl-resins

[3] https://www.gpac.co.jp/en/product/lemalloy/

[4] https://www.findoutaboutplastics.com/2016/09/jack-welch-and-his-uprise-in-ge.html

[5] https://www.findoutaboutplastics.com/2024/08/high-performance-thermoplastic.html

The Sticky Truth About Gluing Plastics: Why Surface Energy Matters (Plastics Processing Rule of Thumb)

Hello and welcome to todays post focusing on gluing plastics.  Ever tried to glue two pieces of plastic together, only for the bond to fail miserably? You're not alone! Gluing plastics can be surprisingly tricky, and a key factor often overlooked is something called surface energy. Think of surface energy as how "eager" a material's surface is to bond with something else. And when it comes to adhesives, eagerness is a good thing!

The Rule of Thumb: High Surface Energy = Stronger Bonds

Here's the golden rule for gluing: the higher the surface energy of a material, the greater the strength of the adhesion you can achieve.

Imagine a tiny water droplet on a surface. On a highly energetic surface, the water spreads out, trying to maximize its contact. On a low energy surface, it beads up, shrinking away. Adhesives behave similarly. They want to spread out and "wet" the surface completely to form a strong bond.

Diving Deeper: High vs. Low Surface Energy Plastics

Plastics are generally categorized into two main groups when it comes to surface energy:

• High Surface Energy (HSE) Plastics: These plastics are generally easier to bond. Their surfaces are more receptive to adhesives, allowing for better "wetting" and stronger molecular interactions.
• Low Surface Energy (LSE) Plastics: These are the notorious "difficult-to-glue" plastics. Their surfaces are less receptive, causing many common adhesives to bead up and struggle to form a lasting bond.

A Quick Look at Surface Energy Values (mJ/m²)

To give you a better idea, below is a small table (Table 1) with approximate surface energy values for some common plastics and other materials. Remember, these values are guides, and specific formulations can impact them.

Table 1: Overview of surface energy values of plastics [1].

As you can see, materials like PTFE (often known as Teflon) have very low surface energy, making them incredibly challenging to bond without specialized adhesives or surface treatments. Another example is the high performance polymer PPS. The surface energy of untreated polyphenylene sulfide (PPS) is typically around 38 mJ/m2. This relatively low surface energy makes PPS challenging to bond to other materials without surface treatment. However, PPS can be treated to increase its surface energy, such as through plasma treatments, which can raise the surface energy to 38 mJ/m2 or higher, depending on the treatment method. In contrast, materials like Polyimide are much more accommodating.

What Does This Mean for Your Next Plastics Gluing Project?

When you're facing a plastic gluing challenge, keep this rule of thumb in mind:

1. Material selection: list gluing as a post-processing operation during part requirement analysis.
2. Identify the Plastic: If you know the type of plastic, you can often infer its surface energy.
3. Opt for HSE Plastics When Possible: If you have a choice of materials, pick higher surface energy plastics for easier and more reliable bonds.
4. Specialized Adhesives for LSE Plastics: For low surface energy plastics, don't reach for your all-purpose super glue. You'll likely need specialized adhesives designed for LSE materials, or consider surface preparation techniques (like primers or plasma treatment) to temporarily increase the surface energy.

Conclusiones

Understanding surface energy is a game-changer for anyone working with adhesives and plastics. By keeping this simple principle in mind, you'll significantly improve your chances of achieving strong, long-lasting bonds and avoid those frustrating gluing failures. Happy gluing!

More Rule of Thumbs can be found in the section "Start here".

Thanks for reading and #findoutaboutplastics

Greetings

Herwig Juster

🔎I review your polymer material selection and plastic part design - contact me here

🔥 There is a problem keeping you awake - My personal website for Polymer Consulting

📊 Discover your Polymer Material Selection score by taking quick test here

Literature: 

[1]https://www.3m.com/3M/en_US/bonding-and-assembly-us/applications/material-bonding/engineered-plastics/

[2] https://www.findoutaboutplastics.com/2025/04/nature-is-built-on-5-polymers-modern.html

Design Data for Engineers: Thermal Aging of PPS Compounds

Hello and welcome to today’s blog post on thermal aging of PPS compounds. During material selection, focus on gathering and understanding all the requirements of the application is essential. Key questions to answer are: What is the service environment of your part? And also: What types of load at which service temperature and time need to be fulfilled?

Thermal aging of Polyphenylene sulfide (PPS) compounds (glass; glass/mineral filled)

High performance polymers such as Polyphenylene sulfide (PPS) offer excellent performance during high heat exposure. PPS mouldings, both filled and unfilled, maintain inherent flame resistance and excellent chemical resistance due to the base resin.

Long-term heat aging results align with the polymer's thermal stability. PPS has a UL 746B continuous use temperature (CUT) of 220°C. It is in a similar range with PPSU which has a CUT of 210°C and PTFE is even above 230°C. 

Figure 1 highlights the good retention of tensile properties in glass and glass/mineral-filled compounds over long-term exposure. An aging test was performed at two temperatures (175°C and 230°C) for a maximum duration of 10,000 hours [2]. 

Figure 1: Thermal aging of PPS compounds (175°C and 230°C; 10,000 hours).

Due to the curing characteristics of cross-linked PPS, aging at temperatures above those in Figure 1 can enhance property retention, attributed to a "case hardening" effect from high-temperature air exposure.

At elevated temperatures, PPS compounds show classical deterioration beyond their glass transition temperature (Tg). Despite crystallinity effects, strength loss is gradual, with significant integrity retained even at 200°C. PPS compounds filled with glass and mineral can retain the tensile properties at both temperatures at a higher level (80% retention rate) compared to glass fiber reinforced PPS compounds (60% retention rate).

Generally, 40% glass-filled mouldings retain about 80% of their original strength at 100°C, 60% at 160°C, and 40% at 200°C.

Conclusion

In conclusion, Polyphenylene sulfide (PPS) compounds demonstrate exceptional performance under high heat exposure, making them a reliable choice for applications requiring thermal stability. Both filled and unfilled PPS moldings exhibit inherent flame resistance and chemical resistance, aligning with the polymer's robust thermal properties. The long-term heat aging results confirm PPS's ability to retain tensile properties, even at elevated temperatures. With a continuous use temperature of 220°C, PPS stands out among high-performance polymers, maintaining significant strength and integrity over time. This makes PPS an excellent candidate for applications demanding durability and reliability in challenging thermal environments. When selecting materials, it is crucial to thoroughly understand the application's requirements, including service environment, load types, and service temperatures, to ensure optimal performance and longevity.

Thanks for reading and #findoutaboutplastics

Greetings

Herwig Juster

🔎I review your polymer material selection and plastic part design - contact me here

🔥 There is a problem keeping you awake - My personal website for Polymer Consulting

📊 Discover your Polymer Material Selection score by taking quick test here

Literature: 

[1] https://www.findoutaboutplastics.com/2024/09/high-performance-thermoplastic.html

[2] Don Brady: Polyphenylene sulfide (PPS), Phillips Petroleum Company

Glass-Fiber Filled PET vs. PBT: Choosing the Champion for Your Application

Hello and welcome to a new blog post. In this post we are comparing glass-fiber filled PET vs. PBT, especially heat distortion properties (HDT). We dive into why PET's higher stiffness, heat resistance, and lower water uptake can be a game-changer for E&E and metal replacement applications. It can help you to elevate your material selection process - let us get started!

PET compounds vs PBT compounds

When it comes to high-performance engineering plastics, glass-fiber reinforced compounds of PET (Polyethylene Terephthalate) and PBT (Polybutylene Terephthalate) are often top contenders. While both offer enhanced strength and rigidity, their distinct properties can make one a clear winner over the other for specific demands. 

One of PET's significant advantages lies in its higher stiffness, which directly translates to reduced creep under sustained loads. This superior mechanical integrity ensures long-term performance where dimensional stability is critical. Furthermore, PET compounds boast a notably higher heat distortion temperature (HDT). Specifically, when measured with HDT/B, PET can exhibit a delta of up to 20°C higher than PBT, making it more resilient in high-heat environments (Figure 1).

Figure 1: Comparison of HDT/A and HDT/B of PET-GF30 and PBT-GF30

Another crucial differentiator is PET's lower water uptake. This property directly contributes to better dimensional stability, as the material is less prone to swelling or warping in humid conditions. In the realm of electrical and electronic (E&E) applications, glass-fiber filled PET truly shines due to its good dielectric properties and the potential for achieving high UL RTI (Relative Thermal Index) values. These characteristics ensure reliable insulation and performance at elevated temperatures.

These combined attributes—superior stiffness, higher heat resistance, better dimensional stability, and excellent electrical properties—make glass-fiber filled PET compounds particularly compelling for demanding applications in the E&E industry. They are also an excellent choice for metal replacement, offering a lighter, often more cost-effective, and corrosion-resistant alternative without compromising on critical performance metrics. When designing your next component, understanding these nuances can lead to superior product design and longevity.

Thanks for reading and #findoutaboutplastics

Greetings

Herwig Juster

🔥 There is a problem keeping you awake - My personal website for Polymer Consulting

📊 Discover your Polymer Material Selection score by taking quick test here

Literature:

[1] https://www.findoutaboutplastics.com/2025/05/4-tips-for-effective-polymer-material.html

[2] https://www.celanese.com/products/rynite-pet

[3] https://www.findoutaboutplastics.com/2025/05/pet-grade-selection-for-diverse.html

[4] https://www.polymermaterialselection.com/selection-examples-blog

When Childhood Crumbles: Understanding Plastic Part Failure in LEGO® Bricks

Hello and welcome to a new post. For many of us, LEGO® bricks are synonymous with durability and endless creative possibilities. They withstand countless builds, deconstructions, and even the occasional barefoot step. So, when a childhood treasure, carefully preserved for decades, suddenly crumbles in your hands, it's a stark reminder that even the most robust plastics have a lifespan. This is precisely the experience my friend Dirk Moses recently encountered with his 1986 LEGO® "Mobile Recovery Vehicle" set, and it offers a fascinating case study into the world of plastic part failure, particularly in ABS.

Dirk's story is a familiar one: a nostalgic journey with his son, building a cherished set from his own youth, only to be met with the disheartening sound of "crack!" as original, seemingly well-preserved parts disintegrated. No sunlight, no moisture exposure – just the relentless march of time. This isn't just a frustrating experience; it's a prime example of how polymers, even when seemingly inert, undergo subtle changes that can lead to catastrophic failure over extended periods.

Figure 1: Broken ABS bricks of the LEGO® "Mobile Recovery Vehicle" set from 1987 [1].

The Material Culprit: ABS and Its Vulnerabilities

The iconic LEGO® bricks are predominantly made from Acrylonitrile Butadiene Styrene, or ABS. ABS is a terpolymer, meaning it's made from three different monomers (check my detailed review on ABS here):

• Acrylonitrile (A): Provides chemical resistance, rigidity, and hardness.
• Butadiene (B): A rubbery component that contributes toughness and impact strength.
• Styrene (S): Offers rigidity, processing ease, and gloss.

This combination gives ABS its desirable balance of properties – stiffness, impact resistance, and a good surface finish – making it an ideal choice for durable toys like LEGO®. However, it's the "Butadiene" component that often holds the key to its long-term degradation.

The Invisible Enemy: Thermal Oxidation of Butadiene

While Dirk meticulously stored his LEGO® set away from sunlight and moisture, he couldn't escape the effects of thermal oxidation. This is a common degradation mechanism in polymers, where oxygen from the air reacts with the polymer chains, often accelerated by even ambient temperatures over extended periods.

The butadiene component in ABS, with its unsaturated double bonds, is particularly susceptible to oxidation. Here's a simplified breakdown of what happens:

1. Initiation: Heat and oxygen initiate the formation of free radicals on the butadiene backbone. These free radicals are highly reactive.
2. Propagation: These free radicals react with more oxygen and then abstract hydrogen atoms from adjacent polymer chains, creating new free radicals. This forms a chain reaction, leading to the formation of hydroperoxides and other oxidized species.
3. Chain Scission and Cross-linking: The hydroperoxides are unstable and can decompose, leading to further free radical formation. This ongoing process results in two primary detrimental effects:

• Chain Scission: The polymer chains break down into smaller fragments. This leads to a reduction in molecular weight and a loss of mechanical strength, making the material brittle and prone to cracking.
• Cross-linking: In some cases, the free radicals can also react with each other to form new covalent bonds between polymer chains, leading to excessive cross-linking. While some cross-linking can increase stiffness, excessive cross-linking makes the material extremely rigid and brittle, also reducing its ability to absorb impact.

In the case of Dirk's 40-year-old LEGO® bricks, it's highly probable that the butadiene in the ABS underwent significant oxidation. This would have caused the once tough and resilient material to become brittle, explaining why parts that felt solid suddenly "cracked" under minimal stress. The internal structure of the plastic had been fundamentally altered at a molecular level, even without external stressors like UV light or repeated use.

The Takeaway for Polymer Engineers and Consumers Alike

Dirk's experience is a valuable lesson for polymer engineers and consumers alike. For engineers, it underscores the critical importance of understanding long-term material degradation mechanisms, even in seemingly stable polymers. Accelerated aging tests are crucial, but real-world shelf-life data, like Dirk's, provides invaluable insights. Developing new additives that can better inhibit thermal oxidation in ABS and other polymers is an ongoing area of research.

For consumers, it's a gentle reminder that even our most cherished plastic possessions have a finite lifespan. While storing items in their original packaging and away from harsh conditions can certainly extend their life, it cannot stop the slow, inexorable march of molecular degradation. During material selection, understanding all the requirements and transforming them into proper part specifications is key to prevent part failure at a later stage.

Dirk's spontaneous shift to a new LEGO® Dreamzzz set for his son, and the "priceless" joy it brought, highlights a beautiful truth: while the physical bricks may crumble, the spirit of play and connection that LEGO® fosters endures, bridging generations even when the plastic sometimes falls apart. And perhaps, for Dirk, his new mission to "quality control" his "Wrinkle Knights" castle will offer further valuable data in the ongoing saga of plastic longevity!

Many thanks to Dirk for sharing with us his experiences! 

Check out my plastics pioneer series - LEGO®-founder Ole Kirk Christiansen & family here

Thanks for reading and #findoutaboutplastics

Greetings

Herwig Juster

🔥 There is a problem keeping you awake - My personal website for Polymer Consulting

📊 Discover your Polymer Material Selection score by taking quick test here

Literature: 

[1] https://www.linkedin.com/posts/dirk-moses-215402191_lego-kindheitserinnerungen-dreamzzz-activity-7332042307308851200-JQfm?utm_source=share&utm_medium=member_desktop&rcm=ACoAABCkmMcBev71cuhh4-jzEaiPHFO5VFb4aO0

[2] https://www.findoutaboutplastics.com/2018/11/reviewing-key-engineering-plastics.html

[3] https://www.polymermaterialselection.com/selection-examples-blog/blog

PET Grade Selection for Diverse Applications - Understanding Intrinsic Viscosity (IV) (Rule of Thumb)

Hello and welcome to a new rule of thumb post. Today we discuss how to select the optimal PET grade (fiber vs sheet vs bottle grade) for your application. 

Figure 1: Selecting the optimal PET grade 

PET Intrinsic Viscosity (IV; dL/g) as a Key Indicator for selection and quality

Polyethylene terephthalate, or PET, is a ubiquitous polymer in our daily lives, from clothing to packaging. John Rex Whinfield and James Tennant Dickson, British chemists, are credited with inventing polyethylene terephthalate (PET) in 1941. They patented the material while working at the Calico Printers' Association of Manchester, building upon early research by Wallace Carothers. By using an aromatic diacid, properties of the resulting Polyester could be improved. This was the major start of PET which became the foundation for synthetic fibers like polyester, Dacron, and Terylene, as well as bottles, and sheets. 

But not all PET is created equal. The key to its diverse applications lies in its Intrinsic Viscosity (IV), a crucial measure of its molecular weight and, consequently, its strength and processing characteristics. This is especially vital when utilizing recycled PET. Figure 2 shows the different process steps in PET production, including the IV obtained at every stage and the resulting potential applications. 

Figure 2: PET process technology and the importance of Intrinsic Viscosity (IV) [4].

Application-Specific IV Ranges

For yarn and fiber applications, where flexibility and drape are paramount, PET with an IV between 0.6 and 0.7 dL/g is preferred. Moving up the scale, 0.7 to 0.8 dL/g PET is ideal for sheet applications, offering the necessary rigidity for thermoforming.

The familiar PET bottles we see daily, typically created through injection moulding into preforms, require an IV of 0.8 to 0.85 dL/g to ensure robust performance. For demanding uses like water jerry cans, where extreme durability is essential, PET with an IV greater than 0.85 dL/g is selected.

Summary of the PET IV ranges: 

• Yarn & Fiber (0.6-0.7 dL/g)
• Sheet (0.7-0.8 dL/g)
• Bottle (0.8-0.85 dL/g)
• Jerry Cans (> 0.85 dL/g)

Choosing the correct IV grade is fundamental for achieving optimal product performance and ensuring efficient processing, highlighting why precise PET grade selection is critical for quality and sustainability across industries.

You would like to optimize your PET bottle - check out his post: Carbonated PET Bottles - Saving Material by Optimization Calculation

More Rule of Thumb posts can be found under "Start here"

Thanks for reading and #findoutaboutplastics

Greetings

Herwig Juster

🔥 There is a problem keeping you awake - My personal website for Polymer Consulting

📊 Discover your Polymer Material Selection score by taking quick test here

Literature: 

[1] https://cirplus.com/learn-and-explore/IV-measurement-for-rpet

[2] https://specialtypolymers.indoramaventures.com/

[3] https://www.alpla.com/en/products-innovations/innovations/pet-wine-bottle

[4] Nexant - the global petrochemical industry, 2017.

5+ Benefits of Incorporating Life Cycle Assessment (LCA) Into Your Plastic Product Design

Hello and welcome to a new blog post in which we discuss the benefits of incorporating Life Cycle Assessment (also referred to as Life Cycle Analysis; LCA) into your plastic product design.

What is a LCA and why is it important?

LCAs are part of the holistic Life Cycle Engineering (LCE) approach and quantify the environmental impacts of plastic products across all stages of their life cycle, including raw material extraction, manufacturing, transportation, use, and disposal or recycling. One can analyze "cradle-to-cradle", where the end of a lifecycle is taken as the end of the recovery process or focus only on "cradle-to-grave", where the end of lifecycle is the disposal of post-consumer plastic waste. In addition, there is also "cradle-to-gate", where the end of lifecycle is taken to be delivery of the product at your factory gate (Figure 1). Altogether, a LCA provides a comprehensive picture of the overall environmental burden associated with a plastic part, allowing designers to identify areas where improvements can be made. 

There are two major standards helping to bring a LCA to reality: 

ISO 14040: providing the principles and framework. 

ISO 14044: provides the roadmap on how to make the LCA. It provides information on the four steps a LCA should contain in order to systematically be able to quantify the environmental impact. 

Figure 1: Overview of Polymer Life Cycle Engineering (LCE) and Life Cycle Assessment (LCA).

What are the four stages of a LCA?

Following is a brief description of the four stages of a Life Cycle Assessment (LCA), which should help you understand the process (Figure 1):

1. Goal and Scope Definition: This initial stage defines the purpose and breadth of the LCA study. It clarifies the product system being assessed, its functions, the intended application of the results, and the audience. This step also outlines the system boundaries, functional unit, and data quality requirements.

2. Life Cycle Inventory (LCI): This stage involves collecting data on all inputs and outputs associated with the product system. This includes raw material acquisition, energy consumption, manufacturing processes, transportation, use phase, and end-of-life treatment. The LCI aims to quantify all relevant environmental exchanges, such as resource use and emissions.

3. Life Cycle Impact Assessment (LCIA): In this stage, the environmental impacts associated with the inventory data are evaluated. The LCIA aims to translate the LCI results into environmental impact categories, such as climate change, ozone depletion, acidification, eutrophication, and resource depletion. Different LCIA methods are available, each with its own set of impact categories and characterization factors.

4. Interpretation: The final and crucial stage involves analyzing the LCI and LCIA results to draw conclusions and make recommendations. This stage assesses the significance of the results, identifies key environmental issues, and evaluates the consistency and completeness of the study. The interpretation should provide clear and transparent conclusions that address the defined goal and scope of the LCA.

The single stages can be supported by software solutions such as GaBi (Sphera) or Echochain. 

What are the benefits of incorporating LCA into your plastic product design?

Currently, over 80% of the product's environmental impact is determined at the design stage. Integrating Life Cycle Assessment right from the design phase of plastic products can unlock some really significant advantages. Here are five key benefits for you to keep in mind:

1. Reduced Environmental Impact: LCA allows you to identify environmental hotspots and by considering the entire life cycle – from raw material extraction to end-of-life disposal – during design, you can actively choose materials and processes that minimize environmental burdens. This includes lower greenhouse gas emissions, reduced water and energy consumption, and decreased waste generation. For example, opting for recycled plastics or designing for easier recyclability can significantly lessen the environmental footprint.

2. Enhanced Resource Efficiency: LCA encourages designers to think critically about material usage and optimize product design for longevity and repairability. This can lead to using less material overall, extending the product's lifespan, and facilitating component reuse or remanufacturing. Think about modular designs that allow for easy replacement of worn-out parts rather than discarding the entire product.

3. Cost Optimization: While the initial LCA might involve some investment, it can lead to significant cost savings in the long run. By identifying resource-intensive stages or materials with high price volatility, designers can explore more cost-effective alternatives. This could involve using less expensive but equally functional materials, replacing metal by high performance polymers, streamlining manufacturing processes, or designing for efficient logistics and waste management.

4. Improved Product Performance and Innovation: The insights gained from an LCA can actually spark innovation and lead to better-performing products. Understanding the environmental constraints and material properties throughout the life cycle can drive the development of novel polymeric materials, innovative designs for durability and functionality, and even new business models like product-as-a-service.

5. Stronger Brand Reputation and Stakeholder Engagement: In today's environmentally conscious world, companies that demonstrate a commitment to sustainability through practices like LCA often build stronger brand loyalty and attract environmentally aware consumers. Transparently communicating the environmental performance of products based on LCA findings can also enhance engagement with stakeholders, including investors, regulators, and the wider community.

6. Informed Decision-Making: By providing a quantitative assessment of environmental impacts, LCAs help designers make more informed choices about polymer material selection, design features, and end-of-life strategies. This can lead to the development of more sustainable plastic parts with a reduced environmental footprint. 

7. Comparing Alternatives: LCAs can be used to compare the environmental impacts of different plastic types, manufacturing processes, and end-of-life management options, helping designers choose the most sustainable approach. This can lead to the development of plastic parts that are not only functional but also environmentally responsible. As an example, Figure 1 compares the Global Warming Potential (GWP) and density of different plastics. 

8. Supporting Circular Economy and Waste Reduction: LCAs are valuable tools for promoting a circular economy for plastics by helping to identify opportunities for reuse, recycling, and remanufacturing. By understanding the full life cycle of a plastic part, designers can create products that are more easily recycled or repurposed, reducing waste and promoting a more circular approach to plastic production. 

Example of a LCA: Packaging 

A LCA was done on 10,000 units of 12oz packages produced in different materials in the United States [10]. In the stage four, (interpretation), a contribution analysis was done, in order to understand the Global Warming Potential (GWP) of the different packaging materials. This in turn allows for better decision making, when the aim is to reduce the product carbon footprint of the packaging material. 

Figure 2 presents the comparison of the GWP of aluminum can, glass bottle and PET bottle. By switching from glass bottle to PET-bottle, a 50% reduction in GWP can be achieved. 

Figure 2: Comparison of GWP of a 12oz bottle made out of glass, aluminum and PET [10].

Conclusion

In conclusion, LCAs are essential tools for promoting sustainable plastic part design by providing a comprehensive and quantitative understanding of the environmental impacts associated with plastic products throughout their life cycle. By using LCAs, designers can identify hotspots, make informed decisions, and develop more sustainable and eco-friendly plastic parts that contribute to a circular economy and a healthier planet. 

Often, a full LCA is not needed, it is better to make a simplified one and focus on one or two key outputs, than to have no LCA done at all. 

Want to deep-dive into designing a sustainable future with polymers? Check out my talk on this topic:

Curious about how Life Cycle Assessment can revolutionize your plastic product design process? Do you have questions about its implementation or the benefits it can unlock? I'd love to hear from you. Contact me here to start a conversation and discover the possibilities.

Thanks for reading and #findoutaboutplastics

Greetings

Herwig Juster

🔥 There is a problem keeping you awake - My personal website for Polymer Consulting

📊 Discover your Polymer Material Selection score by taking quick test here

Literature: 

[1] https://ecochain.com/blog/life-cycle-assessment-lca-guide/

[2] https://www.sciencedirect.com/science/article/abs/pii/S0959652623016086

[3] https://www.sciencedirect.com/science/article/pii/S0921344921000586

[4] https://www.tunley-environmental.com/en/insights/benefits-of-a-life-cycle-assessment

[5] https://www.findoutaboutplastics.com/2022/03/bio-based-polyamides-part-3.html

[6] https://www.findoutaboutplastics.com/2021/12/eco-profiles-of-polymer-resins-global.html

[7] https://www.findoutaboutplastics.com/2023/01/major-benefits-of-plastics-for.html

[8] https://sphera.com/de/loesungen/product-stewardship/life-cycle-assessment-software-and-data/?utm_source=google&utm_medium=paid&keyword=sphera+gabi+software&matchtype=e&device=c&_bt=725390459715&_bk=sphera+gabi+software&_bm=e&_bn=g&_bg=175012151991&campaignid=22030436293&adgroupid=175012151991&feeditemid=&extensionid=&targetid=kwd-1967135919834&loc_interest_ms=&loc_physical_ms=9042558&network=g&devicemodel=&creative=725390459715&placement=&target=&adposition=&gad_source=1&gad_campaignid=22030436293&gbraid=0AAAAADN8CjVUQ_lzuyqI8QmoKWvydnARt&gclid=Cj0KCQjwxJvBBhDuARIsAGUgNfjTc0rXIEVXHZ2qmjUIZbnzLtopaZXPciNnuhj59XIP24MOSYkEPnwaAgzIEALw_wcB

[9] https://phantomplastics.com/shattering-the-plastics-illusion/#flipbook-16085/22/

[10] Franklin Associates, Ltd: Impact of plastic packaging on life cycle energy consumption & greenhouse gas emissions in the United States, 2014

4 Tips for Effective Polymer Material Selection

Hello and welcome to a new post and today I present to you 4 tips for effective polymer material selection. In the realm of plastic product development and engineering, the selection of the appropriate polymer material stands as a pivotal decision, directly influencing the functionality, durability, cost-effectiveness, and overall success of the final product. 

Navigating the vast landscape of available plastics and their diverse properties can feel like traversing a complex terrain. To ensure optimal outcomes, a structured and thoughtful approach is paramount. This guide illuminates four essential tips that will empower engineers and designers to make informed and effective polymer material selections, laying the groundwork for robust and reliable applications.

Let us geht started!

1. Requirement Analysis

• Map out the true part functions, load cases, and material requirements.
• Consider industry standards for properties like flammability, thermal, and electrical characteristics.
• Include qualitative properties such as haptic perception and optical qualities.
• Address legal aspects, manufacturing processes (e.g., injection molding, extrusion), and expected costs.
• Prioritize requirements and summarize them in a worksheet or product requirement document.

2. Questioning

• Ask relevant questions related to the requirements, such as:
• End-use conditions (indoor/outdoor).
• Temperature requirements (minimum, maximum, continuous use).
• Chemical exposure (splash resistance or full submersion).
• Mechanical exposure (load cases, repeatable or static loads).
• These questions help in understanding the requirements better.
• A more detailed list can be found here (incl. download): Material Selection Requirements Checklist

3. Resin Neutral Approach

• Challenge the use of established materials by exploring other material opportunities.
• Question the reasons behind choosing specific resins and whether they truly meet the requirements.
• Encourage re-evaluation of legacy materials and consider alternatives.

4. Decision Making Tools

• Use tools like decision matrix analysis to rank pre-selected materials based on their properties and requirement fulfillment.
• A detailed explanation can be found here
• These tools provide documentation and help understand decisions made by others.

Conclusion

Mastering the art of polymer material selection is an ongoing process of learning and refinement. By diligently applying these four tips – thorough requirement analysis, insightful questioning, maintaining a resin-neutral perspective, and leveraging decision-making tools – you can significantly enhance the effectiveness of your material choices. Embracing this structured approach not only leads to better performing and more cost-efficient products but also fosters a deeper understanding of material science and engineering principles within your team. Ultimately, the thoughtful and informed selection of polymers is a cornerstone of innovation and a key driver in creating successful and sustainable solutions for a wide range of applications.

Ready to begin your journey to Polymer Mastery? Take the Polymer Material Selection scorecard today and discover your POMS score!

Polymer Material Selection scorecard

Also, you can get familiar with the 6 essential polymer material selection skills here. 

My post on 10+ key considerations for selecting the optimal polymer material can help to kickstart your material selection journey too. 

Thanks for reading and #findoutaboutplastics

Greetings

Herwig Juster

🔥 There is a problem keeping you awake - My personal website for Polymer Consulting

📊 Discover your Polymer Material Selection score by taking quick test here

Literature: 

[1] https://www.polymermaterialselection.com/plastic-selection-tools

[2] https://www.findoutaboutplastics.com/2025/03/become-master-in-polymer-material.html

[3] https://www.herwigjuster.com/polymer-consulting