Pumping Plastics - August 2024
Herwig Juster
Your Scout for High Performance Polymers & Material Selection I KAM @ Syensqo I Blogger @ FindOutAboutPlastics.com
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This?monthly digest contains the latest?posts from?my Find Out About Plastics Blog .
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Selecting Thermoplastics: A Practical 5 Step Guide
Selecting the optimal thermoplastic material can be challenging and my aim with this post is to provide you with a practical guide which leads you fast through the selection journey. For a more detailed approach, I created the Polymer Selection Funnel methodology which you can check out here and practical examples in the start here section .
Improper selection of plastics for the application is the leading cause for plastic part failure and since most parts fail along weld lines or knit lines, optimal mould design including filling and processing of the part are crucial too.
The fact that there are almost 100 generic “families” of plastics and additionally with blending, alloying, and modifying with additives results in 1,000 sub-generic plastic types leads to the following crucial question: How should you choose the optimal polymeric material for your part?
Also, selecting the wrong polymer for your product may result in additional financial resources, since the selection process needs to be repeated (including making new tools) or even worse, product failure leads to claims and recalls. The following guide will help you to prevent the major mistakes and if you want to be sure, you can always reach out to a plastic expert to review your selection or help you to select the optimal grade.
High Performance Thermoplastic Selection - Introduction to High Performance Polymers (Part 1)
Welcome to this blog post series on High Performance Thermoplastics selection.
Improper selection of plastics for the application is the leading cause for plastic part failure and since most parts fail along weld lines or knit lines, optimal mould design including filling and processing of the part are crucial too.
Furthermore, there are almost 100 generic “families” of plastics and additionally blending, alloying, and modifying with additives results in 1,000 sub-generic plastic types leads to the following crucial question: How should you choose the optimal polymeric material for your part? Especially, when there are high temperatures, high mechanical requirements, as well as high chemical resistance needs for your application are involved, selecting a high performance polymer will be the key to the solution.
I have chosen a holistic approach to answer the aforementioned questions and therefore structured this post series in five major parts (Figure above):
1. Introduction to High Performance Polymers
2. Short profile of the "magnificent six" families:
-Polysulfides (Polyphenylene sulfide - PPS), Polysulfones (PSU, PESU, PPSU), and Polyarylates (PAR)
-Imide-Based Polymers (PEI, PAI, PESI, TPI, PI) and Polybenzimidazoles (PBI, PBI+PEEK, PBI+PEKK)
-Polyether (PPE, PAEK, PEEK, PEKK)
-Liquid Crystal Polymers (LCP)
-Semi- and Fully Aromatic Polyamides (PARA, PPA, Aramid)
-Polyhalogenolefins (PTFE, PCTFE, FEP, PVDF, ECTFE)
3. Key properties and design data for selection
4. Polymer Material Selection 4-stage funnel methodology
5. Examples for Ultra- and high performance polymer selection
Let us start with the introduction to high performance thermoplastics (HPTs).
Introduction to Ultra- and High Performance Polymers Definitions and classification of high performance thermoplastics
High performance polymers, also often referred to as high heat polymers, can be defined over the continuous use temperature (CUT) by using the Underwriters Laboratory (UL) Relative Thermal Index (RTI). According to the UL 746B, high heat polymers need to withstand a continuous use temperature of 150°C for 100,000 hours (approx. 11 years), while retaining at least half of the initial properties afterwards. Polymers such as PPS and PEEK inherently fulfill this requirement. Conversely, Polyphthalamides (PPA’s) need to be mechanically reinforced and thermal stabilized so that their continuous use temperature can rise from 130°C to 150°C. Most PPA’s have a continuous use temperature between 120°c and 130°C.
Not only are high performance thermoplastics used for high temperature applications. There are low-temperature applications such as aircraft parts, oil rigs, industrial refrigeration, superconducting magnets, and liquid-helium devices, which are exposed to temperatures down to -270°C. Material selection becomes critical to prevent any part failure at such low service temperatures. At temperatures below -40°C, the choice for plastic materials becomes limited and fluoropolymers such as PTFE can be a solution. Most important property of fluoropolymers at low temperatures is their ductility: when reaching the absolute zero temperature point (-269°C), the ductility of these polymers holds at approximately 1%. All in all, fluoropolymers are a good material choice for static seals at low temperatures.
Although HPTs main purpose is to be used at elevated or low temperatures, they possess many other exploitable useful properties as well. For instance, crystalline polymers such as poly(ether ether ketone) and poly(phenylene sulfide) can be found in several room temperature applications due to their superior environmental resistance, in particular to organic solvents and acid and alkaline media.Another definition is over the sales price. Due to their unique properties and added value, HPTs experience low-volume sales at a relatively high selling price. When you compare the ratio of sales price of aliphatic Polyamides to that of high heat polymers, this spreads from 1:3 to 1:20. These ratios vary with the markets the polymers are sold for i.e., automotive, aerospace, electrical-electronic and chemical process industries.
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Condensed Comparison of Plastic Piping Materials for Residential Use (HDPE vs PEX-A, PEX-B, and PEX-C)
Welcome to this post on plastic piping materials used for residential building applications, and mainly we will compare HDPE pipes to PEX-A, PEX-B, and PEX-C pipes.?
Most used plastics in building and construction are polyvinyl chloride (PVC), high density polyethylene (HDPE), expanded polystyrene (EPS), polyurethane (PU), polycarbonate (PC) and polymethyl methacrylate (PMMA). PVC is used for window frames and floorings, HDPE for tubing and piping, EPS and PU for outside and inside insulation. PC and PMMA is used for transparent sheeting applications applied for example at carports. Benefits of using plastics in construction are that they are lightweight, energy efficient, quick and safe installation compared to other materials, cost effective and high resistance to UV and fire.
A detailed example of a polymer material selection for water plumbing pipes can be found here .
Comparison of HDPE and PEX as piping materials
HDPE
My training videos and Shorts
Polymermaterialselection.com is online!
My dedicated website for polymer material selection is online. It contains new online tools for supporting you in your selection journey too.?
If you want me to blog about a specific topic, I invite you to reach out to me here at LinkedIn.
Thank you for your attention!
Greetings,
Herwig Juster
#FindOutAboutPlasticsBlog #PumpingPlastics