Dynamic Mechanical Analysis (DMA) as a Polymer Material Selection Tool

Dynamic mechanical analysis (DMA) provides insights into the mechanical behavior of a material under different conditions. Therefore, it is a powerful tool for polymeric materials selection. In this blog post, I show you why and how you can benefit of it. Polymeric materials are based on long chains of repeating units with inherent high molecular weight. In thermoplastics, the polymer chains are to certain extent entangled. However, they are not chemically bonded to one other, which means they have certain degree of mobility. For instances, disentanglement of the polymer chains can lead to failure of a polymer-based part.

What is DMA?

At its core, DMA is a thermomechanical analytical method that estimates the viscoelastic properties of a given material. It allows you to gain insights into the temperature and time dependency of the tested material. This is achieved by measuring the modulus as a function of temperature, time, or frequency. As a result you will obtain the storage or elastic modulus (E’), the loss or viscous modulus (E’’), and the tangent of the phase angle delta (E’/E’’). In this blog post, I will focus especially on temperature-dependency. During testing some sort of deformation i.e. tension, shear, compression, torsion, or flexure, is applied on the sample material and the modulus is measured. As a result, the material’s elastic modulus (E’) can be plotted against different temperatures. This can be helpful to evaluate the mechanical properties of an existing polymeric part over its service temperature range as well as to decide upon most suitable material to choose according to the application service temperature demands.

What happens on a molecular level?

Most molecular transitions can be made transparent by DMA. For understanding this better, we can have a look at the so-called crankshaft model which explains the molecular chains as a series of joints with emphasis on the change of free volume [2]. There are also more detailed models such as the Doi-Edwards model.

In Figure 1, I sketched the different types of molecular motions and how they are linked to the different temperature transitions. Main movements are slipping of chains, i.e. rotation, bending, and stretching. The gamma transition (Tγ) is the first transition away of the solid state where the first movements of atoms are noticed. With increasing temperature, a secondary transition, also called beta transition (Tβ) happens. Here, 4 - 8 backbone atoms are able to move. Polymers can develop toughness due to increased movement of side chains. With further increase of the temperature the alpha transition (Tα), also called glass transition (Tg). In this case, more than 40 backbone atoms are able to move and mechanical properties drop by one to two powers of ten.

Figure 1: Crankshaft model and type of molecular motions [2].


DMA in action: a useful tool for better decision making in polymer material selection

Let’s have a look at some results of DMA. Figure 2 shows the elastic modulus as a function of temperature for an amorphous polymer such as polycarbonate (PC) and a semi-crystalline polymer such as Nylon (e.g. PA 6). Amorphous polymers show a steep drop in modulus in the region of the glass transition temperature. This is for PC 147°C. For semi-crystalline polymers, such as PA 6 there is also a decrease in modulus at the glass transition temperature, in this case 47 °C. However, in contrast to PC some degree of mechanical strength can be retained from 80 to 180 °C until the crystalline melting temperature of 220 °C is eventually reached.

Figure 2: DMA of an amorphous and a semi-crystalline polymer [1].

Figure 3 shows the elastic modulus as a function of temperature of highly glass fiber filled polyamidimide (PAI), polyphenylene sulfide (PPS) and a thermoset (phenolic). For a room temperature application, PPS and phenolic seem to be the best choice judging from their higher elastic modulus and thus mechanical strength. However, when the service temperature of your application is, for example 130°C a different choice may be more suitable. In this temperature range, PAI is in the lead keeping its high modulus up to 260°C.

Figure 3: DMA of highly filled PAI, PPS and phenolic [1].

Overarching, the most suitable polymer for a certain application obviously depends on the specific application requirements, respectively needed modulus at a certain service temperature or range thereof. As such, the whole DMA curve of a material should be considered during the selection process. In summary, DMA allows you assessing materials’ properties under different circumstances. Material selection has a lot to do with thinking in relationships of time-dependency and temperature-dependency behaviors which can be shown better graphically. Single point data on materials’ technical data sheets (e.g. modulus value at 23 ºC) can lead to misjudgment and negatively impact the material selection process.

Thus, whenever in a discussion with a material supplier or design engineer, discuss how selected materials behave over a wide range of temperatures for instances.

I made an interactive Tableau dashboard which shows the elastic modulus over temperature of amorphous and semi-crystalline polymers (partly also with reinforcements). You can download it and use it for your next polymer material selection project. 

Click here to see the dashboard in full size

I hope this method is useful and helps you in your material selection.


Thanks for reading & till next time!

Greetings

Herwig Juster

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Literature:
[1] M. Sepe - Thermal Analysis of Polymers, Rapra Technology, Shawbury, U.K., 1999
[2] PerkinElmer - Dynamic Mechanical Analysis Basics: Part 2 Thermoplastic Transitions and Properties

Reviewing Key Engineering Plastics - Acrylonitrile Butadiene Styrene (ABS) [incl. Video]

Hello and welcome to this blog post where I will review one of the most famous and versatile plastic ever: Acrylonitrile Butadiene Styrene, or in short ABS. We will review the chemistry, look at the simplified petrochemical flow chart, and discuss the properties of ABS as well as its global demand and producers. I will provide you some price indications and talk about the end uses of ABS too.

1. Chemistry

ABS is an amorphous polymer with a glass transition temperature of 105°C. It is made out of 3 different monomers: Acrylonitrile which provides heat resistance and chemical resistance to strong acids and bases; Butadiene which brings the good impact resistance as well as inferior low temperature resistance; and Styrene which allows ABS to be easily processed and gives it some rigidity.
Where do the three different monomers have their roots?
In general, one can state that 95% of the organic chemical industry is based on seven raw materials (Ethylene, Propylene, C4-Oefins such as Butens and Butadiens, Benzene, Toluene and Xylenes). Those seven starters can be obtained by steam cracking of Naphtha. Therefore, Butadiene is obtained straight after steam cracking the naphtha into its core components.
Acrylonitrile is already more complex. Again you crack Naphtha and get Propylene. In a next step, catalytic ammoxidation of propylene leads to Acrylonitirle. This is also known as the SOHIO process.
Styrene has its foundation in ethylbenzene which is produced by the catalytic alkylation of benzene with ethylene. Then dehydrogenation of ethylbenzene is carried out to obtain styrene. Polymerization of Acrylonitrile with Styrene in the presence of Butadiene particles is done over a continuous mass process.

2. Properties

ABS is a versatile material with a number of good properties. It can be seen as an engineering plastic. However, ABS has limitations at higher temperatures where its physical properties show a sharp decline. As I mentioned in the beginning, the glass transition temperature is around 105°C and the selected application should have a continuous use temperature (CUT) not higher than 90°C. Altogether, we can summarize the properties as follows: ABS has a good stiffness combined with excellent toughness due to the Butadiene content. It shows good electrical properties and has a high gloss. The chemical resistance is good and it is platable. Furthermore, easy coloring is possible: ABS is available in 100’s of colors.

3. Capacity and Manufacturers

The global demand of ABS in 2016 was around 7.9 Million Tons. Asia Pacific is with 74% the highest end user. When we look at the ABS producers, we can say that the top 10 manufacturers provide 71 % of the global capacity. Chi Mei is with 1780 thousand tons per year the largest producer.

4. Price to Performance

A major point in material selection is the cost of plastic. ABS has a moderate cost level and ranges in the lower end of engineering plastics with around 2- 2.5 €/kg.

5. End Uses

ABS has many different end uses, ranging from pipe and fittings, appliance housings, and business machine housings. It is used in automotive parts such as grillers and body parts and due to the high gloss and good appearance it is used in luggage and sports accessories. ABS is known to most of us due to vacuum cleaner housings, LEGO bricks and a bit more unknown but quite interesting is that the car body parts of the Citroen Mehari are made of ABS.

To summarize, this was a review on ABS, a versatile material used in many applications.

Thanks for reading & till next time!

Greetings,

Herwig Juster

New to my Find Out About Plastics Blog – check out the start here section


Literature: Charles P. MacDermott: Selecting Thermoplastics for Engineering Applications

5 Tips For Choosing The Optimal Polymer Resin Supplier

5 Tips For Polymer Resin Supplier Selection by Herwig Juster

Today, I will provide you with 5 tips which can support you when selecting a polymer resin supplier. Apart of selecting the optimal material for your product, selecting the optimal resin supplier plays an as important role too. So, let’s get started:


Tip number 1: Broad product portfolio
Look for a resin supplier which has a broad product portfolio and therefore can take a polymer-neutral approach. The supplier should be able to recommend the optimal chemistry to fit the application. With a good recommendation, over or under engineering can be minimized.


Tip number 2: Customer-supplier interaction leads to a solid relationship
The supplier needs to listen to the customer. This is necessary to properly translate the end product’s requirements into the optimal material properties. This includes things such as understanding the type of environment the material will be exposed to, and/or understanding the regulatory requirements for that specific market. By the end, the supplier needs to determine if there is a fit between its products and the customer needs.


Tip number 3: Technical support, especially when you deal with high performance polymers Customer, doesn’t matter if OEM or Tier 1, Tier 2, they all require a quick turnaround on samples, quotes, or answers to general product related question. In general, a material supplier should have a technical staff that can support the customer from ideation to commercialization and even further. This includes application development engineers who work with the customer to fine-tune their process to best run the materials on the processing machine. Another support can be in-house of the supplier itself by providing design and launch support such as filling simulations and FEA analysis. Prototyping facilities can be a help to test first ideas. Application engineers can help in metal to plastics, weight and cost reduction projects. Solving production issues and minimizing down time for trialing materials completes the support.


Tip number 4: Good suppliers have in-house regulatory teams
Regulatory requirements are becoming more challenging whether the polymer is used in manufacturing medical devices, packaging, automotive, or consumer products dealing with food. A regulatory team is a must have to keep up with regulatory changes on a global scale. Different markets have different regulatory bodies and the supplier needs to be up to date and ensure the standard in different world regions. The best is to have regulatory teams which consist out of product safety experts with a global approach on regulatory affairs. With that, integrity of the raw materials and finished goods is kept on a global level.


Tip number 5: Global and local-to-local supply
For global active companies which run operations in Asia, America and Europe, having a local sales and technical support is important. For example, when an OEM designs a product in North America support is needed there. And when the product from this OEM will be manufactured by a contractor in Asia, material and support needs to be there too. Especially with complex part designs and/or manufacturing processes it is helpful when sales and technical staff are involved firsthand in order to make the best product recommendations.


Bonus Tip: Dual sourcing
For certain application it can be beneficial to have a second supplier validated as a backup. This takes up some time upfront, however it can pay off when the supply situation of the primary source has troubles.

Altogether, using those tips can help you in your decision process to find the optimal supplier.
Thanks for reading and till next time!
Herwig Juster


New to my Find Out About Plastics Blog – check out the start here section.

High Heat Plastics (HHP) Demystified incl. Cheat Sheet

Introduction to high heat plastics

High heat plastics (HHP’s), as part of the specialty polymers group, found their ways in several industries from automotive to medical devices. As their name already suggests, these are able to continuously withstand high heat conditions. Generally, thermoplastic and/or thermoset polymers which maintain useful mechanical properties at temperatures in the range of 150°C and above [1, 2] can be defined as HHP’s. Furthermore, HHP’s exhibit high strength, toughness and long-lasting properties even when several doses of different types of radiation for sterilization are applied [4].

Due to their unique properties and added value, HHP’s experience low-volume sales at a relatively high selling price [2]. When you compare the ratio of sales price of aliphatic nylons to that of high heat polymers, this spread 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. Although HHP’s main purpose is to be used at elevated temperatures, they possess many other exploitable useful properties as well. For instances, 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 [2].

Nowadays, specialty polymers account for approximately 0.3% of the global polymer production volume. For examples, in 2016, the global production of plastics summed up to approximately 335 million metric tons of which one million metric tons were specialty polymers.

A bit of background on how it all started

A good example of how researchers learned and applied the aforementioned properties and principles was the replacement of natural silk by using nylon 6, 6 and nylon 6. Nylon was introduced by Wallace H. Carothers of DuPont and Paul Schlack of I.G. Farben in the late 1920’s. Silk is an expensive material which has superior quality and performance. The first synthetic fibers were expensive too, since polymer science and engineering was still in its children shoes. Nevertheless, challenges were progressively overcome which paved the way to produce synthetic fibers in high quality, quantity and at low cost. Several more high performance plastics were one after the other explored and commercialized over the following decades. An early representative was poly(phenylene sulfide), which was a byproduct of the chemical reaction of benzene and sulfur in the presence of aluminum chloride by Friedel and Crafts in 1888. In 1982 General Electric Plastics, respectively J. Wirth introduced the polyetherimide (PEI) resin under the trade name Ultem which was. Another example is the synthesis of poly(aryl ether ketones) (PAEK’s) by Johnson from Union Carbide in the late 1960’s.

High temperature plastics grew up – Classification of HHP’s

The classification into amorphous and semi-crystalline polymers which is also known from commodity and engineering thermoplastics can be done with HHP’s as well. Amorphous representatives are polysulfone (PSU), poly (ether sulfone) (PES), polyetherimide (PEI) and poly(amide imide) (PAI). Semi-crystalline representatives are semi-aromatic Nylons (PARA, PPA), poly (phenylene sulfide) (PPS), high performance poylesters (LCP, PCT), fluoropolymers (PTFE, PFA/MFA), poly(ether ether ketone) (PEEK), and poly(ether ketone) (PEK). The latter, especially when filled with glass, carbon, and minerals keep useful mechanical properties above their glass transition temperature (Tg). PEEK, for example, has a Tg of 148 °C but its continuous service temperature is 250 °C. An overview of classification by a plastics thermometer is shown in Figure 1.

Figure 1: High heat plastics thermometer.

Why can certain thermoplastics withstand high temperature loads?

The answer can be found in the chemical composition. Key building blocks are, for example, aromatic rings and carbon-oxygen double bonds. In this context, polymer performance can be tailored during synthesis by balancing the ratio of rigid, non-contorted units such as aromatic rings to flexible, easily-contorted units such as aliphatic bonds. HHP’s are usually produced by means of step-growth polymerization processes, i.e., polycondensation and polyaddition [3]. These allow greater design freedom and properties control than chain-growth polymerizations.

The replacement of aliphatic units with aromatic ones imparts increased resistance to chain degradation by heat and associated oxidation in the resulting polymers. While eventually formed free radicals cannot be stabilized by surrounding bonds in aliphatic polymers, these are easily stabilized by resonance in aromatic polymers. As a result, chain scission and degradation is prevented. Accordingly, a complete aromatic polymer such as polyparaphenylene should show an optimum in stability. Investigations have shown that it is thermally stable above 500°C [4]. The biggest downside is its inherent unprocessability, a result of the high stiffness of its chains. To keep up with processability demands, flexible linkages such as C-O, C-S, C-C are incorporated in HPP’s.

Figure 2 shows the continuous use temperature of commodity, engineering and high heat plastics [2].

Figure 2: Continous Use Temperature (CUT) of thermoplastics with 150°C borderline in red for high heat plastics.

“Ultra polymers” – hidden champions among HHP’s?

On the very upper end of our plastics thermometer you can find the thermoplastics polyimide (TPI) and poly(amide-imide) (PAI) as amorphous representatives and poly(benzimidazole) (PBI) as a semi-crystalline representative. These polymers are regarded as “Ultra polymers” due to their outstanding thermal and mechanical properties. For examples, unfilled PAI is the polymer with highest tensile strength up to 260°C continuous use. PBI is the polymer with the highest Tg, 427°C. In addition, it does not burn. Overall, it is used in applications where highest demand in temperatures, harsh chemicals, and plasma environments are necessary, e.g. fire protection clothing. It is possible to cast PBI into a coating, film or membrane [6, 7].

Who are the main suppliers of HHP?

In the table below, an overview of the major suppliers of HHP’s is given. It should be seen as a living document which can change over the years since chemical companies merge or sell certain portfolios.

My HHP cheat sheet – what you find in there

I tried to capture the most interesting and important material data and transformed it into a cheat sheet which allows you to have all in one infographic. It has three property sections (mechanical, thermal and processing) and represents the following polymer groups:

• Polysulfones

• Polyimides

• Polyphylensulfides

• Semi-aromatic Nylons

• Polyaryletherketones

• Liquid Crystal Polymers

• Fluoropolymers

This time it was a longer post and I hope you have enjoyed this blog post. The cheat sheet can be useful e.g. for a first comparison in the material selection phase.

What are your experiences with HPP’s? Leave a comment below!

Thank you for reading and till next time!
Greetings, Herwig Juster

P.S. New to my blog – check out the start here section


Literature:
[1] http://www.craftechind.com/13-high-performance-plastics-used-in-the-automotive-industry/
[2] Vinny Sastri: Plastics in medical devices
[3] D. Parker, J. Bussink, H. van de Grampel, et al., Polymers, High-Temperature, Ullmann’s Encyclopedia of Industrial Chemistry, DOI: 10.1002/14356007.a21_449.pub3
[4] Raymond B. Seymour and Gerald S. Kirshenbaum: High Performance Polymers: Their Origin and Development
[5] http://cen.acs.org/articles/94/i9/chemical-companies-investing-high-end.html?type=paidArticleContent
[6] Johannes Karl Fink High Performance Polymers, Second Edition (Plastics Design Library)Jul 1, 2014
[7] http://pbipolymer.com/about/celazole-pbi-advantage/

What The Media Does Not Tell You About Ocean Plastics

Ocean plastics: what the media does not tell you

The presence of plastics in our oceans has been increasing over the last decade. Currently, about 8 million tons of plastics reach the oceans every year. This is obviously alarming. In this blog post, I will give you complementary insights into the “Ocean Plastics” topic which are not covered by the media. This is intended to help you understanding that while banning (certain) plastics maybe the solution, this does not necessarily have to be the solution.

Let’s start with some facts already proven [1]:

• At the current ocean pollution rate, we will have more plastic than fish by 2050

• Most plastic waste is washed into the oceans by rivers

• 90% of it derives mainly from 10 rivers

• 8 are in Asia: the Yangtze, Indus, Yellow, Hai He, Ganges, Pearl, Amur, Mekong

• 2 are in Africa: the Nile and the Niger

The aforementioned rivers are located in highly populated regions which additionally lack of functional waste management systems. This certainly relates to the high degree of poverty of these regions as well. When people live in fierce conditions having to fight for basic goods such as clean water and food on a daily basis, environmentally friendly waste disposal does not seem big of a concern.

Most of the “ocean plastics” originate from packaging. The consumption of plastics in packaging holds at 35 % of the total plastics consumption. However, not using plastics for food packaging, for instances, would decrease the lifetime of fresh food (meat and vegetables) and increase food waste as the consequence. Besides packaging, plastics play a key role in the constitution of medical devices, aircraft and airspace, automotive, electronics and industrial applications.

When collected by a functional waste management system such as those implemented in developed countries, packaging derived plastic waste can be thermally recycled and serve as energy source. Most of the packaging plastic is based on low cost polyethylene and polypropylene. Both are rich sources of carbon considering their hydrocarbon chemical nature.

In my view, tackling this problem has a lot to do with the increase of wealth in poor and emerging countries as well. When wealth is increased, societies can afford basic care, i.e., food and proper housing on a daily basis. With the basic living requirements fulfilled, they can start taking care of things such as their gardens and streets. Then societies will not want to have plastic bags lying around and dirtying their scene. They will put pressure on governments to handle the waste in a proper way. Governments will have now the financial power to implement and supervise waste management systems which will prevent plastics from ending up into the oceans.

Nevertheless, fact is that we still need to clean up the plastic waste in the ocean. The positive message is that several startups are already successfully testing their cleaning innovations, just to name one here: Boyan Slat’s The Ocean Cleanup shows how you can clean the water with a piping system down to 5 meters [2]. They use the fact that plastic has a low density and stays on the surface and upper water layers. When you think of how many other things are already drowned to the bottom of the ocean, oceans’ plastics clean up may yet offer us a chance to clean up this mess as well.

I hope I could broaden your consciousness about the topic “Ocean Plastics” by bringing to you a complementary view to that that our media is transporting.

Check out Episode 2 here

Thanks for reading and till next time!

Greetings,

Herwig Juster

Literature:
[1] https://www.weforum.org/agenda/2018/06/90-of-plastic-polluting-our-oceans-comes-from-just-10-rivers
[2] https://www.sciencealert.com/ocean-plastic-collector-pollution-great-pacific-garbage-patch-ocean-cleanup

The Organic Chemical Industry - 95% wt Based On Just Only 7 Raw Materials [Infographic]

Hello and welcome to this infographic showing you how only seven raw materials are responsible for 95% wt of products in the organic chemical industry.

Enjoy and thank you for reading!

Greetings,

Herwig

P.S. New to my blog – check out the start here section

Infographic: "The Organic Chemical Industry"

Interested to talk with me about your polymer material selection, sustainability, and part design needs - here you can contact me 

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Polymeric Material Selection: In 6 Steps To The Optimal Polymer For Your Application

If you are a designer, application engineer, material engineer, or material purchaser dealing with e.g. automotive parts, you will have one major question in mind to bring forward your projects: which polymeric material fulfills the job based on the set criteria in the optimal way and costs? To take the guess work out, I will show you in this blog post how you can determine the optimal polymeric material in six steps [1]. In this way you can keep track of your material decision making process.

Step 1 - Define key criteria for your part: Main task here is to proper estimate the requirements of the part which can be based on performance criteria, appearance criteria, and cost targets (part costs, tooling costs and equipment costs). Step 2 - Selection of the manufacturing process: there are several things to consider when selecting the manufacturing process of your part. On one hand, it is the part size, part complexity, and allover product volumes. On the other hand, you have equipment costs. For example, costs of an injection moulding machine in case a new one is needed and tooling costs. Production volumes are the driving force here, followed by tooling costs. The material cost can vary from 50% (technical parts) up to 80% (consumer parts) of your manufacturing costs. The economic batch size varies for the different processing techniques:

- Injection moulding: 10^4 – 10^6 units

- Blow moulding: 10^5 - 10^7 units
- Compression moulding: 10^3 – 10^5 units
- Rotational moulding: 10^3 – 10^4 units
- Thermoforming: 10 – 10^3 units
- Polymer casting: 10 – 10^3 units
- Resin transfer moulding: 10^3 – 10^6 units

Step 3 – Create a short list of materials: After we estimated the key criteria and manufacturing process it is time to create a short list of potential material candidates. A grouping into chemical family such as polyolefines, aliphatic nylons, semi-aromatic nylons, polyesters, polysulfones, fluoropolymers, polyketones, polyimides, and so on is useful. Furthermore, grouping by primary additives such as fiber (glass, carbon) reinforcement, tougheners, heat stabilizers, flame retardants is helpful at this stage too. Additionally, you can look for plastic material suppliers in online databases such as Pro-Plast  or you can work with online selection guides such as these ones: Omnexus and PlasticsFinder. Furthermore, CAMPUS material database offers a comparison of hundreds of grades and their properties in an uniform way (every resin supplier who contributes to CAMPUS tests their materials in the same way).

Step 4 – Evaluation of your data: now the feasibility study can start by evaluating the material data of the chosen polymers for mechanical, chemical, electrical, process ability, post-processing capabilities such as laser welding, painting or metallization. Since some load cases of the final part are available, structural analysis can be done too. Cost analysis is crucial for some end markets such as automotive and it needs to be included at this stage. The same is valid for supply chain and global availability of the suggested materials. The complexity of the analysis can vary and timewise it can take days or some months to obtain conclusive results.

Step 5 – Develop your prototypes: now you dive into the product development phase, which has an iterative character. In this phase, the focus is kept on detailed engineering. It is usually the longest phase and it allows you to create prototypes, test them, and re-iterate. Your material selection list will get more focused and some materials might fall off the list. In corporations, this phase can take place in the Research & Development (R&D) departments. There, engineers and scientists test and approve the different materials or they approve a process where the material is integrated. Product development groups have usually the product itself as an output. In some cases, the material needs to be first approved by the R&D for general design use that it can appear on the selection list for certain parts in the Product Development group.

Step 6 – Selection of the material: in the final step, selection takes place. The selection should be already pretty obvious and it should be not a surprise anymore which material will be used in the product. The selected plastic fulfills all the set criteria, including cost effectiveness. Implicit knowledge is turned into explicit results which allow a fact-based decision. If the decision is not yet easy and clear to take, then it is best to revise some of the steps, especially the starting steps. It will cause some time delays and is still better to take the extra loop since a wrong material choice now will lead to potential higher costs in the future. It is always useful to cross-check the results and the suggests with the resin supplier since they have in-house know-how build up on their materials including lots of testing and actual applications.

So, those were the 6 steps for selecting an optimal polymeric material for your application. You can use it as a checklist when you make your next material selection. For further reading I would like to recommend this post dealing with big data and material selection.

Thanks for reading & till next time!
Greetings, Herwig Juster


New to my Find Out About Plastics Blog – check out the start here section


Literature: [1] Eric Larson - Thermoplastic Material Selection: A Practical Guide

Polymer Processing: Tolerance and Roughness Charts

Hello and welcome to this blog post on tolerance and roughness charts for different polymer processing techniques. This post supports you in the polymer shaping selection as part of the material selection process.

1. Tolerance chart: A part will not be exactly shaped to a specified dimension. There will be a deviation Δx from a desired dimension x which is allowed by the specifier. This is in general referred to as tolerance T which is defined as e.g. x =100 ± 0.1mm, or as 0.01. The bar chart allows selecting different polymer processing techniques to achieve a desired tolerance.

2. Roughness chart: A part will have different surface roughness R, which is measured by the root-mean square amplitude of the irregularities on the surface. A rough surface will have an R < 100 μm and a high polished surface has a R < 0.01 μm. The bar chart allows selecting different polymer processing techniques to achieve a desired surface roughness.

Thanks for reading!
Greetings and till next time,
Herwig Juster


New to my Find Out About Plastics Blog – check out the start here section.

Literature:
[1] Granta - Material and Process Selection Charts, 2010

10 Fluoropolymer Facts for Designers & Engineers

Fluoropolymers are used nowadays in several industries and applications like flexible tubing, packaging, cooking equipment, wear and friction parts.

In the table below you can find an overview of the thermoplastic fluoropolymer family.

What is their secret and why are they used in high-end applications?

In this blog post I made a fact list which will answer those questions:

1. Fluoropolymers contain a carbon-fluorine bond which is very polar with a very high bond strength leading to very low intermolecular attractions.
2. Based on this, fluoropolymers have very low surface energy, a low coefficient of friction and are lipid, water and stain repellant.
3. Fluoropolymers have both: low and high temperature resistance; furthermore they have excellent dielectric properties and are chemically inert.
4. When blended with other polymers, fluoropolymers will bloom to the surface due to the very low surface free energy (lubricous behavior).
5. Latest market studies implicate that the global fluoropolymer market will be worth over $8.8 billion by 2019 and thought to be between 80,000 and 90,000 tons.
6. Roy J. Plunkett accidently discovered one of the most famous fluoropolymers (Teflon by DuPont) in 1938.
7. PTFE, PVDF, FEP and ETFE are the most common used fluoropolymers.
8. Among the fluoropolymers, PTFE has with 0.1 the lowest coefficient of friction.
9. Most fluoropolymers are fully fluorinated olefinic (aliphatic based) materials and homopolymers contain over 99% fluorine by weight which makes them most resistant to chemicals.
10. Fluoropolymers are melt processable except of PTFE and PVF.

Here some more honorable mentions:

1. For the semiconductor industry fluoropolymers are vital. Without them, you would not read this blog post on your computer, tablet or smartphone.
2. ETFE can be used as a glass replacement: The Allianz Arena in Germany uses ETFE panels.
3. Coatings out of PTFE are used in high temperature applications up to 290°C e.g. for coating of bakery equipment.
4. The world’s largest manufacturers of fluoropolymers include DuPont, Daikin, Solvay, Dyneon, and Asahi Glass.

5. 

   Infographic - 10 Fluoropolymer Facts for Designers and Engineers

   
   
   

I hope you enjoyed this fact list.

Thanks for reading and till next time!

Greetings,

Herwig Juster


New to my Findoutaboutplastics Blog – check out the starthere section.

Literature:

[1] https://www.fluorotec.com/blog/21-fluoropolymer-facts-for-engineers/

[2] https://www.solvay.com/en/markets-and-products/featured-products/fluoropolymers-faq.html



Polymer densities: "You know your're a plastics engineer if..."

...you know the specific density of most polymers without having to look it up."

Still, having a repository of 318 polymers with their specific density at hand can help you in certain material selection decisions.

Enjoy the table and thanks for reading!

Thanks to Scientific Polymer Products for the data.

Greetings, Herwig

P.S. New to my blog - check out the start here section.

  

Chemical Name	Density (g/cc)
Poly(4-methyl-1-pentene)	0,83
Poly(1-pentene)	0,85
Ethylene/propylene/diene terpolymer-50% ethylene/4% diene	0,86
Ethylene/propylene copolymer-60% ethylene	0,86
Poly(1-butene)	0,86
Poly(1-hexene)	0,86
Poly(1-octadecene)	0,86
Polypropylene, atactic	0,866
Polymethylhexadecylsiloxane	0,88
Polymethyltetradecylsiloxane	0,88
Ethylene/butylene copolymer, dihydroxy terminated	0,88
Ethylene/butylene copolymer, monohydroxyl terminated	0,88
Poly(vinyl n-decyl ether)	0,883
Polymethyloctadecylsiloxane	0,886
Poly(1,4-pentadiene)	0,89
Poly(methyl n-tetradecyl siloxane)	0,89
Poly(methyl n-octadecylsiloxane)	0,89
Poly(vinyl n-dodecyl ether)	0,892
Poly(1,4-butadiene)	0,892
Polypropylene, isotactic	0,9
Polybutadiene, cis	0,9
Polybutadiene, cis & trans-36% trans	0,9
Poly(vinyl 2-ethylhexyl ether)	0,904
Polyisoprene	0,906
Polybutadiene, dicarboxy terminated	0,907
Poly(1,2-butadiene)	0,909
Polymethylhexylsiloxane	0,91
Styrene/ethylene-butylene, ABA block copolymer-29% styrene	0,91
Polydimethylsilane	0,91
Polybutadiene oligomer, acrylated	0,91
Polymethyloctylsiloxane	0,91
Poly(methyl n-octylsiloxane)	0,91
Styrene/butadiene copolymer-5% styrene	0,91
Poly(methyl n-hexylsiloxane)	0,91
Poly(vinyl n-octyl ether)	0,914
Poly(1-butene), isotactic	0,915
Styrene/isoprene, ABA block copolymer-14% styrene	0,92
Polyisobutylene	0,92
Poly(isobutylene-co-isoprene)-2.2% isoprene	0,92
Polyethylene, low density	0,92
Poly(vinyl sec-butyl ether)	0,92
Poly(vinyl isopropyl ether)	0,924
Poly(butadiene-co-acrylonitrile), dicarboxy terminated-10% acrylonitrile	0,924
Ethylene/vinyl acetate copolymer-18% vinyl acetate	0,925
Poly(vinyl n-hexyl ether)	0,925
Poly(vinyl n-butyl ether)	0,927
Ethylene/vinyl acetate copolymer-9% vinyl acetate	0,928
Poly(lauryl methacrylate)	0,929
Poly(dodecyl methacrylate)	0,929
Poly(isobutylene-co-isoprene), brominated-1,5% isoprene, 2.1% bromine	0,93
Polyethylene, oxidized	0,93
Ethylene/acrylic acid copolymer-5% acrylic acid	0,93
Ethylene/ethyl acrylate copolymer-18% ethyl acrylate	0,93
Polybutadiene, phenyl terminated	0,93
Poly(vinyl isobutyl ether)	0,93
Ethylene/vinyl acetate copolymer-14% vinyl acetate	0,932
Styrene/butadiene copolymer-23% styrene	0,935
Poly(butadiene-co-acrylonitrile), amine terminated-10% acrylonitrile	0,938
Styrene/butadiene, ABA block copolymer	0,94
Polydimethylsiloxane, ethoxy terminated	0,94
Ethylene/vinyl acetate copolymer-25% vinyl acetate	0,948
Polyethylene, high density	0,95
Ethylene/methacrylic acid ionomer, sodium ion	0,95
Poly(p-t-butyl styrene)	0,95
Poly(vinyl ethyl ether)	0,95
Poly(vinyl cyclohexane)	0,95
Ethylene/methacrylic acid ionomer, zinc ion	0,95
Ethylene/vinyl acetate copolymer-28% vinyl acetate	0,951
Ethylene/vinyl acetate copolymer-33% vinyl acetate	0,952
Poly(butadiene-co-acrylonitrile), dicarboxy terminated-18% acrylonitrile	0,955
N-Vinylpyrrolidone/vinyl acetate copolymer-30% N-vinyl pyrrolidone	0,955
Poly(butadiene-co-acrylonitrile), amine terminated-16.5% acrylonitrile	0,956
Poly(butadiene-co-acrylonitrile), dicarboxy terminated-21.5% acrylonitrile	0,958
Polyisoprene, trans	0,96
Poly(butadiene-co-acrylonitrile), dicarboxy terminated-26% acrylonitrile	0,96
Poly(methyl vinyl ether/maleic acid), monobutyl ester	0,962
Styrene/butadiene copolymer-45% styrene	0,965
Octadecene-1-maleic anhydride copolymer-20% maleic anhydride	0,97
Acrylonitrile/butadiene copolymer-22% acrylonitrile	0,97
Acrylonitrile/butadiene copolymer-21% acrylonitrile	0,97
Acrylonitrile/butadiene copolymer-29% acrylonitrile	0,97
Polydimethylsiloxane	0,97
Poly(n-octyl methacrylate)	0,971
Poly(tetramethylene ether) glycol	0,979
Ethylene/vinyl acetate copolymer-40% vinyl acetate	0,98
Ethylene/vinyl acetate copolymer-45% vinyl acetate	0,98
Polydimethylsiloxane, dihydroxy terminated	0,98
Polydimethylsiloxane, dimethylamine terminated	0,98
Polydimethylsiloxane, acetoxy terminated	0,98
Poly(propylene oxide), monoamine terminated	0,98
Acrylonitrile/butadiene copolymer-33% acrylonitrile	0,98
Poly(vinyl n-butyl sulfide)	0,98
Poly(vinylmethylsiloxane)	0,98
Polyoxytetramethylene	0,98
Poly(butadiene-co-acrylonitrile), vinyl terminated-16% acrylonitrile	0,985
Acrylonitrile/butadiene copolymer-38% acrylonitrile	0,99
Acrylonitrile/butadiene copolymer-27% acrylonitrile	0,99
Acrylonitrile/butadiene copolymer-45% acrylonitrile	0,99
Ethylene/vinyl acetate copolymer-50% vinyl acetate	0,99
Acrylonitrile/butadiene copolymer-31% acrylonitrile	0,99
Acrylonitrile/butadiene copolymer-44% acrylonitrile	0,99
Polymethylhydrosiloxane	0,99
Poly(1,2,2-trimethylpropyl methacrylate)	0,991
Poly(neopentyl methacrylate)	0,993
Poly(propylene oxide), diamine terminated	0,9964
Poly(propylene oxide), diurea terminated	0,9989
Poly(vinyl stearate)	1
Polydimethylsiloxane, chlorine terminated	1
Acrylonitrile/butadiene copolymer-43% acrylonitrile	1
Acrylonitrile/butadiene copolymer-51% acrylonitrile	1
Acrylonitrile/butadiene copolymer-41% acrylonitrile	1
Poly(propylene oxide)	1
Poly(t-butyl acrylate)	1
Poly(3,3-dimethylbutyl methacrylate)	1,001
Poly(propylene oxide), triamine terminated	1,003
Poly(propylene glycol)	1,005
Poly(1,3-dimethylbutyl methacrylate)	1,005
Poly(n-hexyl methacrylate)	1,007
Poly(dimethylsiloxane-co-ethylene oxide), AB block-25% dimethylsiloxane	1,007
Nylon 12 [Poly(lauryllactam)]	1,01
Poly(1-methylpentyl methacrylate)	1,013
Poly(1,4-butylene adipate)	1,019
Poly(vinyl propionate)	1,02
Poly(t-butyl methacrylate)	1,022
Poly(o-methyl styrene)	1,027
Poly(1-methylbutyl methacrylate)	1,03
Poly(isopentyl methacrylate)	1,032
Poly(n,n-dimethyl-3,5-dimethylene piperidinium chloride)	1,033
Poly(isopropyl methacrylate)	1,033
Poly(4-methylstyrene), monocarboxy terminated	1,04
Poly(4-methylstyrene)	1,04
Nylon 11 [Poly(undecanoamide)]	1,04
Poly(2-ethylbutyl methacrylate)	1,04
Poly(vinyl n-pentyl ether)	1,041
Poly(isobutyl methacrylate)	1,045
Poly(dimethysiloxane-co-diphenylsiloxane)-80% dimethylsiloxane	1,05
Polystyrene, monomethacrylate terminated	1,05
Polystyrene, monohydroxy terminated	1,05
Poly(vinyl methyl ether)	1,05
Polystyrene, 90% syndiotactic	1,05
Polystyrene	1,05
Poly(5-phenyl-1-pentene)	1,05
Poly(sec-butyl methacrylate)	1,052
Poly(n-butyl methacrylate)	1,055
Polyethyleneimine, epichlorohydrin modified	1,055
Polydiethoxysiloxane	1,06
Ethylene/vinyl acetate copolymer-70% vinyl acetate	1,06
Poly(2,6-dimethyl-p-phenylene oxide)	1,06
Poly(isobutyl acrylate)	1,06
Poly(isobornyl methacrylate)	1,06
Polyphenylene oxide	1,06
Poly(dimethylsiloxane-co-ethylene oxide), AB block-18% dimethylsiloxane	1,066
Poly(dimethylamine-co-epichlorohydrin), quaternized	1,07
Nylon 6/12 [Poly(hexamethylene dodecanediamide)]	1,07
Poly(diethylene triamine-co-adipic acid)	1,07
Polyethyleneimine	1,07
Poly(caprolatone)diol	1,07
Poly(caprolatone)triol	1,073
Poly(alpha-methylstyrene)	1,075
Nylon 6/9 [Poly(hexamethylene nonanediamide)]	1,08
Poly(ethylene oxide), diamine terminated	1,08
Poly(isopropyl acrylate)	1,08
Polyethyleneimine, 80% ethoxylated	1,08
Poly(n-propyl methacrylate)	1,08
Styrene/acrylonitrile copolymer-25% acrylonitrile	1,08
Nylon 6/10 [Poly(hexamethylene sebacamide)]	1,08
Nylon 6/6 [Poly(hexamethylene adipamide)]	1,08
Styrene/allyl alcohol copolymer-6% hydroxyl	1,083
Poly(vinyl butyral)-11% hydroxyl content	1,083
Poly(vinyl butyral)	1,083
Poly[2,2-propane bis[4-(2,6-dimethylphenyl)]carbonate]	1,083
Poly(ethylene sebacate)	1,085
Poly(n-butyl acrylate)	1,087
Butyl methacrylate/isobutyl methacrylate copolymer-50/50 copolymer	1,09
Poly(methyl m-chlorophenylethylsiloxane)	1,09
Poly(alpha,alpha-dimethylpropiolactone)	1,097
Poly(ethylene glycol mono-methyl ether)	1,097
Polystyrene sulfonic acid	1,1
Polyethylene, chlorinated-25% chlorine	1,1
Polysulfone, anionic	1,1
Polymethacrylonitrile	1,1
Poly(cyclohexyl methacrylate)	1,1
Poly(methyl m-chlorophenylsiloxane)	1,1
Poly(vinyl butyral)-19% hydroxyl content	1,1
Poly(ethyl methacrylate)	1,11
Polymethylphenylsiloxane	1,11
Poly(methylphenylsiloxane)	1,11
Poly(acryloxypropylmethylsilane)	1,11
Poly(p-cyclohexylphenyl methacrylate)	1,115
Vinyl alcohol/vinyl butyral copolymer-80% vinyl butyral	1,12
Nylon 6(3)T [Poly(trimethyl hexamethylene terephthalamide)]	1,12
Poly(vinyl methyl ketone)	1,12
Nylon 6 [Poly(caprolactam)]	1,12
Poly(ethyl acrylate)	1,12
Poly(2,2,2′-trimethylhexamethylene terephthalamide)	1,12
Poly(1-phenylethyl methacrylate)	1,129
Poly(2-ethyl-2-oxazoline)	1,14
Ethyl cellulose	1,14
Poly(2,6-diphenyl-1,4-phenylene oxide)	1,14
Polycaprolactone	1,143
Poly(1,2-diphenylethyl methacrylate)	1,147
Poly(t-butylaminoethyl methacrylate)	1,15
Poly(2-hydroxyethyl methacrylate)	1,15
Poly(styrene oxide)	1,15
Polyethylene, chlorinated-36% chlorine	1,16
Poly(diphenylmethyl methacrylate)	1,168
Poly(ethylene succinate)	1,175
Poly(benzyl methacrylate)	1,179
Styrene/maleic anhydride copolymer-75% styrene	1,18
Phenoxy resin	1,18
Poly(vinyl methyl sulfide)	1,18
Poly(methacrylic acid), sodium salt	1,18
Poly(ethylene adipate)	1,183
Poly(ethylene azelate)	1,183
Polyacrylonitrile	1,184
Poly(vinyl acetate)	1,19
Poly(1,4-cyclohexylidene dimethylene terephthalate)	1,196
Polydiphenoxyphosphazene	1,2
Poly(methyl methacrylate)	1,2
Poly(n-vinyl carbazole)	1,2
Polycarbonate	1,2
Bisphenol A polycarbonate	1,2
Poly[1,1-(1-phenylethane) bis(4-phenyl)carbonate]	1,2
Poly(ethylene glycol)	1,207
Poly(methylene-co-guanidine), hydrochloride	1,21
Poly(ethylene-co-chlorotrifluoroethylene)	1,21
Poly(phenyl methacrylate)	1,21
Poly(ethylene oxide)	1,21
Polyethylene, chlorinated-42% chlorine	1,22
Poly(methyl acrylate)	1,22
Polyimidazoline, quaternized	1,22
Polychloroprene	1,23
Cellulose propionate	1,23
Poly(vinyl formal)	1,23
Poly(methylene[polyphenyl isocyanate)]	1,24
Polysulfone	1,24
Poly[4,4′-isopropylidene diphenoxy di(4-phenylene)sulfone]	1,24
Poly(sec-butyl alpha-chloroacrylate)	1,24
Poly[methane bis(4-phenyl)carbonate]	1,24
Poly(n-butyl alpha-chloroacrylate)	1,24
Polyethylene, chlorinated-48% chlorine	1,25
Zein, purified	1,25
Polyoxymethylene	1,25
Poly(N-vinyl pyrrolidone)	1,25
Poly(cyclohexyl a-chloroacrylate)	1,25
Poly(diallyl isophthalate)	1,256
Cellulose acetate butyrate	1,26
Poly(diallyl phthalate)	1,267
Poly(tetramethylene isophthalate)	1,268
Poly[1-(o-chlorophenyl)ethyl methacrylate]	1,269
Polysulfide rubber	1,27
Styrene/maleic anhydride copolymer-50% styrene	1,27
Poly(isopropyl a-chloroacrylate)	1,27
Polyethylene, chlorosulfonated	1,28
Poly(vinyl alcohol)	1,29
Poly(n-propyl a-chloroacrylate)	1,3
Poly(methyl y-trifluoropropylsiloxane)	1,3
Poly[2,2′-(m-phenylene)-5,5′-bibenzimidazole]	1,3
Polyacrylamide	1,302
Poly(methyl alpha-cyanoacrylate)	1,304
Polybutadiene terephthalate	1,31
Cellulose acetate	1,31
Cellulose triacetate	1,31
Poly(2-chloroethyl methacrylate)	1,32
Poly(m-trifluoromethylstyrene)	1,32
Vinyl chloride/vinyl acetate copolymer-81% vinyl chloride	1,33
Poly(ethylene-2,6-naphthalenedicarboxylate)	1,33
Poly(ethylene phthalate)	1,338
Poly(ethylene isophthalate)	1,34
Poly(2,2,2-trifluoro-1-methylethyl methacrylate)	1,34
Vinyl chloride/vinyl acetate copolymer, carboxylated	1,35
Poly[thio bis(4-phenyl)carbonate]	1,355
Polyepichlorohydrin	1,36
Vinyl chloride/vinyl acetate copolymer-90% vinyl chloride	1,36
Poly(phenylene sulfide)	1,36
Poly(B-propiolactone)	1,36
Vinyl chloride/vinyl acetate copolymer-88% vinyl chloride	1,37
Methyl vinyl ether/maleic anhydride copolymer-50/50 copolymer	1,37
Poly(p-phenylene ether-sulphone)	1,37
Poly(3-chloropropylene oxide)	1,37
Poly(vinyl fluoride)	1,38
Poly(ethylene terephthalate)	1,385
Hydroxyethyl cellulose	1,39
Hydroxypropyl methyl cellulose	1,39
Vinyl chloride/vinyl acetate/vinyl alcohol terpolymer-91% vinyl chloride, 3% vinyl acetate	1,39
Poly(vinyl chloride), carboxylated	1,39
Methyl cellulose	1,39
Poly(ethyl a-chloroacrylate)	1,39
Polyimide	1,4
Poly(vinyl chloride)	1,4
Poly(acrylic acid)	1,41
Vinylidene chloride/vinyl chloride copolymer-5% vinyl chloride	1,41
Poly[2,2-propane bis[4-(2,6-dichlorophenyl)]carbonate]	1,415
Polyacetal	1,42
Poly[N,N’-(p,p’-oxydiphenylene)pyromellitimide]	1,42
Poly(4-fluoro-2-trifluoromethylstyrene)	1,43
Poly(p-hydroxy benzoate)	1,44
Poly(p-oxybenzoate)	1,44
Melamine cellulose	1.45-1.52
Poly(vinyl chloroacetate)	1,45
Melamine formaldehyde	1,48
Poly(3,3,3-trifluoroethylene)	1,58
Alginic acid, sodium salt (algin)	1,59
Cellulose nitrate	1,6
Poly(glycolic acid)	1,6
Polyisoprene, chlorinated	1,63
Vinylidene chloride/acrylonitrile copolymer-20% acrylonitrile	1,65
Poly(vinylidene chloride)	1,66
Poly(vinylidene fluoride)	1,76
Poly(hexafluoropropylene oxide)	1,91
Polychlorotrifluoroethylene	1,92
Poly[2,2-propane bis(4-(2,6-dibromophenyl)]carbonate]	1,953
Nafion 117, hydrogen ion form	1,98
Poly[2,2-hexafluoropropane bis[4-(2,6-dibromophenyl) carbonate]	1,987
Melamine	2
Phenolic resins	2
Poly(tetrafluoroethylene)	2
Poly(2,4,6-tribromostyrene)	2,1
Poly[tetrafluoroethylene-co-perfluoro(alkyl vinyl ether)]	2,15
Source: http://scientificpolymer.com/density-of-polymers-by-density/