How To Turn Thermoplastics Carbon Neutral Or Even Carbon Negative? Here Is An Effective Way

Hello and welcome to a new blog post. Today we are going to discuss how to turn thermoplastics carbon negative in an effective way. 

In previous posts I presented to you the Global Warming Potential (GWP) of different plastics vs. their density as well as the GWP values of thermoplastics compared to their different thermal properties and transitions: Tg, heat capacity (Cp), short term temperature exposure (HDT) and long term temperature exposure (UL Yellow Card).

Among the materials and chemicals, thermoplastics have already a low GWP value. Gasses such as methane (CH4) have an estimated GWP of 27-30 over 100 years, and the average cement has a GWP of 600-800  kg CO2 eq / ton. Most thermoplastics are in the range of 2 -8 kg CO2 eq / ton. 

Is it possible to have carbon negative thermoplastics?

Yes, by using specific fillers which are able to lock in more carbon dioxide than they release in a later stage. In the following we discuss two filler examples: biochar and hemp. 

Biochar

Seth Kane [2] and his team demonstrated that carbon-neutral composite materials can be produced by adding biochar. They evaluated  it over a cradle-to-gate life cycle assessment. Biochar was added as a filler in recycled HDPE (rHDPE), virgin HDPE, bio-based polylactic acid (PLA), and polyhydroxybutyrate (PHB).  In general, biochar fillers lock carbon in a stable form and this in a permanent way. Key results were that 40 w% biochar filler is sufficient for rHDPE to reach 0 kg CO2 equivalent. PLA requires 50 w% biochar filler to be considered 0 kg CO2 equivalent. And HDPE needs 52 w% to reach carbon neutrality (Figure 1). Furthermore they found out that biochar increases the tensile strength of rHDPE by 45%, and stiffness by 126%. Also the flexural storage modulus could be improved by 79% however all over the compound was more brittle. They concluded that adding biochar linearly reduced the GWP potential of the examined plastics by up to 3.3 kg CO2 equivalent per kg of material compound. 

Figure 1: Overview polymers with biochar filler to reach 0 kg CO2 eq. GWP

Hemp

In a similar situation we have hemp as a filler. It can be used with PP as base polymer in Automotive applications (door panels, seat backs paneling, bumpers, spoilers). Apart from cost and weight reduction, using hemp additives reduces the carbon footprint too. Industrial hemp additive manufacturer Heartland [4] demonstrated a carbon footprint reduction of virgin plastics by as much as 44%. 

Conclusions

Biochar and hemp used as fillers in thermoplastics are an effective way to reduce the carbon footprint. Together with recycling of thermoplastics (including fillers, and compounds) as well as other mitigation strategies such as bio-based plastics, usage of renewable energy in plastics manufacturing will reinforce the advantage of plastics over other so-called green materials in the long run. 

Greetings and #findoutaboutplastics

Herwig 

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

Subscribe to my Polymer Material Selection book launch page 

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

My YouTube channel

Literature: 

[1] https://www.madeofair.com/

[2] https://www.sciencedirect.com/science/article/pii/S2666682022000226#sec0007

[3] https://www.sciencedirect.com/science/article/pii/S0959652620338956

[4] https://www.businesswire.com/news/home/20220124005281/en/Heartland-and-Ravago-Develop-Products-to-Reduce-the-Carbon-Footprint-of-Plastic

[5] https://www.researchgate.net/figure/Global-warming-potential-GWP-range-for-cementitious-Environmental-Product-Declarations_fig3_341943113

[6] https://www.findoutaboutplastics.com/2022/02/design-data-for-plastics-engineering.html

Flame Retardant Classifications According DIN EN ISO 1043-4 - What do they mean?

Hello and welcome to a new blog post. In a previous post we discussed flame retardants in a general way, followed by examples of flame retardants for Polyamides. In this post we uncover the flame retardant classification according to DIN EN ISO 1043-4.

Example of a part marking code with flame retardant

Let us begin with an example and let us decode it step-by step: PE-LD FR (30+40) 

PE-LD: Polyethylene with low density

FR (30+40): contains flame retardant form classification 30 and 40

What does the classification FR(30+40) mean?

To find out we need to have a look into the DIN EN ISO 1043-4 where we can find the different flame retardant types. 

Figure 1 shows an extract of the most common flame retardant classes. We can distinguish between halogen compounds, nitrogen compounds, halogen-free organophosphorus compounds,inorganic phosphorus compounds, metal oxides, Boron and zinc compounds, silicon compounds, and graphite.

Figure 1: extract of the most common flame retardant classes according DIN EN ISO 1043-4

Cycling back to our example, we can state that this PE-LD uses nitrogen compounds (3) and halogen-free organophosphorus compounds (40) as flame retardants.

In case you want to overmould copper (busbar application) with a Polyamide which needs a certain flame retardant level, attention should be given to use flame retardants from classification 40. Such flame retardants do not create electrical corrosion on your part which in turn can cause a short circuit. 

In market segments such as automotive, more and more flame retardant material in combination with other properties like thermal conductivity are used. Using Figure 1 during material selection can help to prevent part failure in the long run for example due to electrical corrosion (migration of flame retardants on surface). 

Thank you for reading and #findoutaboutplastics

Greetings, 

Herwig 

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

Subscribe to my Polymer Material Selection book launch page 

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

My YouTube channel

Literature:

[1] https://www.findoutaboutplastics.com/2022/06/flame-retardants-why-do-we-need-them.html

[2] https://webstore.ansi.org/Standards/DIN/dineniso10432016-1640336

[3] https://www.wikiwand.com/de/ISO_1043

[4] https://plastics-rubber.basf.com/global/en/performance_polymers.html

What Should be the Minimum Transparency Level Required for Plastic Laser Welding? (Community Question Answered)

 Hello and welcome to a new blog post. Today we discuss a question I received regarding plastic laser welding. The basics of plastic laser welding I described herein this post which includes an introduction training video too. 

What should be the minimum transparency level required for plastic laser welding?

In general, thermoplastics transmit a near-IR beam. The upper plastics layer needs to have transparency for wavelengths between 808 nm – 1064 nm. A minimum transmission rate of 5% is required, however optimal would be 30% and greater (Figure 1). 

That means in an optimum application case,  30% of the laser energy passes through the transparent upper layer and is absorbed by the lower layer. Additives, fillers, pigments, and part thickness can negatively influence the transmissivity of your upper layer. Therefore, careful polymer material selection for laser welding is needed. 

Figure 1: Plastic laser welding - minimum and optimum transparency level of upper layer

Thanks for reading and #findoutaboutplastics

Greetings, 

Herwig 

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

Subscribe to my Polymer Material Selection book launch page 

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

My YouTube channel

Literature: 

[1] https://www.findoutaboutplastics.com/2021/03/joining-techniques-laser-welding-of.html

[2] https://youtu.be/0T_sQwbWFMA

[3] https://www.solvay.com/en/product/amodel-1145-hs-lzt-bk-979

[4] https://www.lpkfusa.com/articles/lq/LPW_GL_Hybrid_Laser_Wedling_Design_Guidelines.pdf

Ways to Increase the Comparative Tracking Index (CTI) of Thermoplastics (Community Question)

Hello and welcome to a new blog post. I received a question on how to improve the Comparative Tracking Index (CTI) of thermoplastics and in this post we will discuss this question since it can be of value for the whole community. 

The basics of CTI and its measurement I discuss in this training video. 

In general, there are polymers which more likely form a conducting carbonized path compared to other polymers. Aliphatic and semi-aromatic polymers, polyolefins, fluoropolymers, as well as polyesters show high resistance to form a conductive carbonized path. PPS on the other hand more likely forms a conducting carbonized path, combined with a low tracking resistance. Important in this context are the two standards IEC 60112 and UL 746 which are used in several industries to rank CTI of polymers. Figure 1 shows an overview in which CTI class (IEC and UL) different thermoplastics can be placed. 

Figure 1: Overview CTI of different thermoplastics

Ways to improve the CTI value

-Use a mineral flame retardant: By adding 8 weight % of mineral flame retardant to a PBT, CTI could be increased 13%.  Example is the ACTILOX® 200SM (Nabaltec).

-Use additives: there are multi-functional polyester modified siloxane additives which can be used to improve the CTI of various engineering compounds. Example is the TEGOMER® H-Si 6441 P (Evonik).

-Blending with a high CTI polymer: in the case of PPS, adding polyamide can improve the CTI value from 175 V (PPS-GF40) to 275 V (PPS-GF40+PA). Example is the Ryton XK2430 (Solvay). 

Electrical design properties such as the CTI is important during the material selection of components  for e-mobility and electronic applications. Choosing the optimal polymer can lead to a more compact design which is the case for busbars overmoulded with a thermoplastics. A high CTI polymer allows you to shorten the distance between the busbars. 

Thanks for reading and #findoutaboutplastics

Greetings, 

Herwig Juster

Interested to talk with me about your polymer material selection, 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

My YouTube channel

My personal website

Literature:

[1] https://www.toray.eu/eu/plastics/torelina/technical/tec_021.html

[2] https://www.plastic-additives.com/en/application-areas/cable-electronics

[3] https://nabaltec.de/fileadmin/user_upload/03_produkte/03-3_boehmit/nabaltec_tds_actilox-b30-b60-200sm.pdf

[4] https://www.solvay.com/en/product/ryton-xk2340

[5] https://www.youtube.com/watch?v=LzFyKr-SUZQ