UV-stabilization of Polyamides (aliphatic and semi-aromatic) - Effective Protecting of Applications against Exposure to Weather

Hello and welcome to this blog post in which we have a look at the UV-stabilization of Polyamides and how effective protection of your applications against exposure to weather can be achieved. 

In a past post we already discussed the weather and UV resistance of styrene copolymers and PMMA. 

In case one of your requirements of your application is long-term outdoor usage, then additional protection considerations of your polymer need to be taken into account during polymer material selection. 

What is the difference between UV Stabilized and UV Resistant?

UV stabilized:  adding stabilizer to your base polymer in order to have protection towards long-term degradation from UV light. They prevent damage by absorbing or screening out UV radiation. The best results being achieved with carbon black.

UV resistant: there are polymers which are inherently resist against UV rays and prevent UV degradation. Examples are polymers such as PMMA and high performance polymers (PEEK, PAI, PPS, PEI, PBI).

UV stabilization of Polyamides

For aliphatic Polyamides such as PA 6.6, adding 2 wt% of carbon black is resulting in a good protection against UV radiation. 

Same is valid for semi-aromatic Polyamides such as the PolyArylAmide (PARA; MXD6), where 2 wt% up to 5 wt% will result in an excellent UV protection. 

Example cable tie fasteners used for terrestrial photovoltaic (PV) modules- PA66 vs PA66 UV stabilized

HellermannTyton and Germany’s Fraunhofer Institute for Solar Energy Systems ISE investigated the impact of their cable tie fasteners which are used to fix cables of PV modules [3].  The test was 1,600 hours long using a test chamber were the cable ties were exposed to a UV dose of 156.78 kWh/m2 (equals the natural solar irradiation of 1,000 kWh/m2 per year). Altogether, this testing time corresponds to 3 years of outdoor exposure. The cable ties are made out of standard PA66, UV stabilized PA66, and PA11.

Figure 1 shows the results of the test, which indicates a reduction of loop pull strength of around 86% for the standard PA 66. The reduction of the UV stabilized PA 66 is minimal and the PA11 even shows a constant performance, which makes the PA11 a suitable outdoor material without needing too much additional protection. 

Figure 1: Results of the 1600 hours UV test of PA66, PA66 UV stabilized and PA 11 cable ties [3].

Thanks for reading and #findoutaboutplastics

Greetings 

Herwig Juster

Interested in having a second opinion on your material selection and high performance polymers, including price evaluation or  discuss with me about your current sustainability, and part design needs - here you can contact me 

Interested in my monthly blog posts – then subscribe here and receive my high performance polymers knowledge matrix.

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

Interested in our material solutions - check out our product page here

My YouTube channel

My personal website

Literature: 

[1] https://www.usplastic.com/knowledgebase/article.aspx?contentkey=601

[2] https://wurth-international.com/app/uploads/2016/10/CableTies_Technical_Information_2011.pdf

[3] https://blog.hellermanntyton.com/markets-and-industries/1275/uv-stability-hellermanntyton-products-tested-fraunhofer-ise

Pumping Plastics 2023 - My New Book "Pumping Plastics" is Now Available as Paperback Worldwide on Amazon!

Dear community, 

welcome to this special book update! 

Pumping Plastics 2023 is now available as book

The waiting has an end - Pumping Plastics 2023 book is available as paperback. On 185 pages it contains over 50 posts on various polymer engineering topics such as 

-polymer material selection examples, 

-high performance polymers (PARA and PPS), 

-design properties for plastics professionals, 

-bio-polyamides, sustainable materials, 

-and three guest interviews. 

The book can be read chronologically from month to month, but not necessarily. You can also directly jump to the post(s) of your interest.

As a bonus, the first chapter of my first book "Polymer Material Selection" is included.

I invite you all to have a look and grab a copy.

Don’t forget to check out the Pumping Plastics book from 2022 here too, as well as my Polymer Material Selection book. 

Thanks and #findoutaboutplastics,

Herwig 

Guest Interview with Harrison McVeigh Carroll, Business Manager for the Plastics and Packaging Industry at Pivot Search

Hello everyone and welcome to this guest interview. Today I present to you Harrison McVeigh Carroll who is Business Manager for the plastics and packaging industry at Pivot Search, which is a recruitment business that embraces flexibility, autonomy, trust & innovation.

In this guest interview, we have the chance to learn about the current recruitment industry, and in particular the plastics industry, as well as the value he brings to the plastic industry networks.

Enjoy the interview!

1. Tell us about yourself, your current role, and your company Pivot Search.

Business Manager at Pivot Search leading the industrial team and with 6 years experience recruiting in the plastics and packaging space globally. We are in our 4th year as a business and try to do things differently, our unique model hires only experienced, successful recruiters who get given complete flexibility in regard to where they work and as a company have gone from strength to strength focusing on developing relationships with our clients and are continuing to do so!

2. What trends are you currently seeing in the recruitment industry, and in particular the plastics industry? 

In the Plastic industry in the past 12 months I have seen a huge change in the market to being candidates lead. What I mean by this is experienced candidates with a high technical or commercial skillset in compounding, high performance plastics and additives for example are so in demand that they have more choice than ever when seeking a new role. This is leading to companies needing to be more agile, it is not enough anymore to set guidelines for a position and expect candidates to be interested due to simply the name of the company alone. Depending on particular role, candidates are not needing to relocate, take less than a 10% pay increase or settle for less in any sense.

The companies that are realising this, who are moving quickly and not leaving candidates waiting due to this shift in the market, are the ones who are winning the talent in most cases.

I also believe that the value of the plastics industry which I know your Blog is dedicated to is solidifying the industry. A lot of people I speak with are noticing the upward market trend of using the material, which at one stage in the not-so-distant past was seemingly becoming the 'enemy' to things like global warming with its links of the obvious difficulties to reuse. However, the alternates have been proven to not be all that and this goes beyond just Packaging the obvious example. The uses in construction, Aerospace and Automotive industries to name just a few prove that plastic is vital in our everyday life and when used correctly there isn't a material that can compare – the industry is certainly not going anywhere, and the growth plans and manufacturing increases from a couple of the companies I have been working with this year alone so far are a great example of that.

3. What are the reasons and rationale behind these trends?

I think we are now feeling the market boom following COVID. Just a couple years on when the market was tough certainly from a recruitment industry, companies in most part 'shut up shop' and a lot of promoting from within and being agile with the team they had. And from a candidate side it was risky to make a move and suddenly be in probation period in a new role, if something went wrong you would be the first line of fire if something goes badly from a business aspect. But now this has settled massively, and I know myself life is more or less the same as pre covid. And the market is reflecting this, but different to before it seems a much larger % of the market are looking to hire all at once and this has lead to candidates having that choice which means it is companies who are having to change their methods, or face being left behind and missing out on the best talent.

4. Based on the aforementioned information, what value can you bring to the plastic industry networks to improve the situation?

As always throughout my career I have tried to add more than just being a recruiter to my network. Whilst I will never claim to be a chemist or engineer, I try and learn the industry going the extra mile examples being the articles I have carried out and talks with people like yourself, and other KOL in the industry. In addition to this, it is important I don't lose sight of my role and what companies employ me and the team at Pivot to do. To bring top talent in the industry to them and the best way we can break this down is for starter learning the need of the company, where, who and what product experience is a nonnegotiable. Once this step is done, now we face the above-mentioned challenge of seeking the candidates. Using my network which I have built up recommendations is a big way I am able to either source candidates or be pointed in the right direction.

Screening the candidates specifically to companies need is then the leg work required, a linkedin search is no longer enough in this very competitive recruitment space. And results speak for themselves, we are working across Central Europe and North America with some of the best compounding, packaging and high-performance polymer businesses there are and building relationships that mean we are their first port of call when they face a challenge to source candidates.

5. Where can the readers find out more about you and your offers for the plastic industry?

Reaching out on LinkedIn is always the best place to start. Whether it's a candidates seeking a new role or a company looking to bring great talent, its always great to connect whether it be for now or in the future.

That was the guest interview with Harrison form Pivot Search – many thanks Harrison for our exchange on topics such as recruiting trends in the plastics industry and ideas on how to improve current challenges in the staffing of companies.

Thanks for reading!

Greetings and #findoutaboutplastics

Herwig Juster

Design Properties for Engineers: Coefficient of Linear Thermal Expansion (CLTE) of Glass Fiber Reinforced High Performance Polymers as a Function of Temperature

Hello and welcome to a new post in which we discuss the coefficient of linear thermal expansion (CLTE) as an important design data for polymer material selection. In general, CLTE is a performance indicator for the dimensional stability of materials when they are exposed to temperature. In general, plastics expand under the influence of temperature. The expansion is big compared to other materials. Length changes of millimetres at a temperature difference of 10 Kelvin are not unusual.

Furthermore, the effect of thermal expansion is different depending which polymer processing technique is used (injection moulding vs. extrusion). Different values are obtained in polymer flow direction and perpendicular to the flow direction. Thermal expansion is lower in flow direction compared to perpendicular to it.

Altogether, CLTE in flow and perpendicular direction is influenced by: 

-filler type, 

-filler amount, 

-the flow orientation (anisotropy),

-and the temperature.

CLTE (Coefficient of linear thermal expansion) of glass fiber reinforced high performance Polymers as a function of temperature

Knowing the CLTE of reinforced high performance polymers as a function of temperature allows you to better assess the suitability for your application. In case the continuous use temperature of your application is between 150°C and 160°C, the CLTE values in this range are helpful. 

Figure 1 shows the CLTE of glass fiber reinforced Polyphenylene sulfide (PPS), Polyphthalamide (PPA), Polyethersulfone (PESU), and Liquid Crystal Polymer (LCP) in flow direction. LCP has an extremely low CLTE (similar to metals) and it behaves almost linear over the temperature change However, in perpendicular direction, similar to other properties, the CLTE of LCP becomes larger over the temperature due to the anisotropy with glass fiber filling. 

Figure 1: CLTE (Coefficient of linear thermal expansion) of selected high performance polymers as a function of temperature [1]. 

CLTE of metals compared to high performance polymers - Example PEEK-GF 30wt%

Figure 2 compares the CLTE of a Polyether ether ketone (PEEK) with a 30 wt% glass fiber reinforcement to a Zinc alloy, an Aluminum alloy, and a stainless steel [2]. PEEK-GF30 wt% is able to compete in terms of CLTE in flow direction with the aforementioned metals which enable metal replacement or overmoulding of metal structures. A similar case is true for Polyarylamide (PARA; MXd6) with 50 wt% glass fiber reinforcement which has in flow direction a similar CLTE as steel and brass [3]. 

Figure 2: CLTE of PEEK-GF30 wt% as a function of temperature vs. metals [2].

Figure 3 compares the CLTE of PEEK to PEEK-GF 30wt% and PEEK-CF 30wt% as a function of temperature. It can be seen that carbon fibers are more effective in reducing the CLTE. At temperatures of 200°C, the differences between GF and CF are minimal, however compared to PEEK unfilled they are large.

Figure 3: Comparsion CLTE of PEEK vs. PEEK-GF 30wt% and PEEK-CF 30wt% [2].

Additional posts on this topic: 

Plastic Part Design Properties for Engineers - CTE/ CLTE of Polymers, Mineral Fillers and Metals

Design Properties for Engineers: Coefficient of Linear Thermal Expansion (CLTE) of High Performance Polymers

Plastic Multipoint Design Data - CLTE of Polymers as a Function of Temperature

Thanks for reading and #findoutaboutplastics

Greetings,

Herwig Juster 

Interested in having a second opinion on your material selection and high performance polymers, including price evaluation or  discuss with me about your current sustainability, and part design needs - here you can contact me 

Interested in my monthly blog posts – then subscribe here and receive my high performance polymers knowledge matrix.

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

Interested in our material solutions - check out our product page here

My YouTube channel

My personal website

Literature: 

[1] https://www.sumitomo-chem.co.jp/sep/english/products/lcp/lcp_bs_sunpo.html

[2] Ketaspire KT-820 GF30: https://www.solvay.com/sites/g/files/srpend221/files/2018-07/ketaspire-peek-design-and-processing-guide-en.pdf

[3] https://www.findoutaboutplastics.com/2023/11/design-properties-for-engineers-abcs-of.html