My Material Insights From The K Fair 2019



In the past two weeks in October the famous K Fair, the world’s number 1 fair for plastics and rubber took place in Düsseldorf, Germany.

I visited the K fair too and in this blog post I highlight the new material developments and launches of the major plastic manufacturers including new compounds as well.

Let’s start in alphabetic order:

Akro Plastic:

Akro Plastic presented new PPA compounds based on homopolymer 9T (Akromid T9). This 9T based PPA has lower water absorption in comparison with PA 6T.

Furthermore, it shows a better flowability and faster crystallization. In addition, they presented with Akromid B28 LGF40 a long glass fiber product which chemically couples PA6 and PP to a blend which enables better flow compared to pure PA 6. It has a higher conditioned strength compared to PA 6 glass fiber 50% compound.

BASF:

BASF highlighted aside of electrification of automotive industry also the fuel cell powertrain as a future mobility concept. They showed a media distribution system which was a joint project with Joma-Polytec GmbH and Mercedes-Benz Fuel Cell GmbH. BASF developed two tailor-made PA 6.6, i.e. Ultramid® A3WG10 CR and A3EG7 EQ. These grades are used now to make anode- and cathode-end plates in the fuel cell stack. Here, the purity of the material is extremely important, especially in the media distribution plate and water separator unit, where materials are exposed to cooling water, air and hydrogen.

Apart of fuel cells, BASF showed their advances in the so-called ChemCycling project, which aims at utilizing the pyrolysis oil obtained from mixed plastic waste for new polymer generation. As a result, they have now Ultramid® B3WG6 Cycled Black 00564. The latter can be used for front-end carriers in automotive.

Borealis:

Borealis introduced their new plastics recycling technology called Borcycle. The major grade named Borcycle MF1981SY, filled with 10% talc, contains more than 80% recycled polyolefins. Visible appliance applications are in the focus of use for this material. Borcycle claims to fulfill the stiffness and impact requirements needed in such applications.

DSM:

DSM launched bio-based grades of their Arnitel® thermoplastic copolyester (TPC) and Stanyl® PA 4.6, which use 25-42% bio-based feedstock. Bio-based Stanyl® grades have already the globally recognized sustainability certification ISCC Plus.

Furthermore, DSM offers now Akulon RePurposed PA. This polyamide contains recycled nylon-based fish nets.

DuPont:

DuPont presented their Zytel long chain nylon 6.12 for blow moulded cooling pipes. It is a technology that can be transferred to electric cars and gains traction there.

EMS Chemie:

EMS presented their new grades of Grilamid TR: XE 11248 and FE 11292. These are both transparent high-performance polyamides especially developed for the medical application market. Grilamid TR XE 11248 has high flexural strength and improved alcohol resistance. Grilamid TR FE 11292 can be sterilized with steam over hundreds of cycles and can be used in combination with silicon (LSR).

Further highlight was the use of Grivory G5V and Grivory HT6 for advanced metal replacement. Grivory HT6 shows a 50% higher stiffness at 140°C compared to standard PPA.

Evonik:

Evonik increases their Vestamid® PA 12 capacity by over 50% between 2019 and 2021, which shows the commitment to capture more market, especially in the automotive tubing market.

Lanxess:

Lanxess communicated that it is collaborating with artificial intelligence company Citrine Information to apply AI in the development of customized plastics. They see glass fiber sizing customization a way to cut down the time to market. For high voltage connectors in electric vehicles, Lanxess offers now UL yellow card certified orange (RAL 2003) PA and PBT compounds.

Polyplastics:

Polyplastics presented their new Durafide® PPS grade entitled 6150T73 which has outstanding heat shock resistance and high mouldability. This grade addresses the need of having resins which can be used for overmoulding metal parts in automotive power control units (mainly electric cars) and withstand harsh automotive environments (-40°C/ +150°C). Furthermore, they introduced WW-09, which is a new Duracom® POM grade. It combines high strength with good creep and sliding properties.

Sabic:

Sabic unveiled their Lexan® polycarbonate based on certified renewable feedstock. PC is part of their Trucircle circular solution and allows customers to reduce CO2 emissions.

Solvay:

Solvay launched a new high Tg PEEK called Ketaspire® PEEK XT. Solvay belongs to the group of material suppliers bringing a new polymer to the market place. It has exceptional chemical resistance with a 20°C higher glass transition temperature compared to standard PEEK. There are already polyketones which have a similar high Tg, however their chemical resistance is lower than the Ketaspire® XT. The XT portfolio covers neat resins (XT-920), glass fiber reinforced compounds (XT-920 GF30), and carbon-fiber reinforced compounds (XT-920 CF30).

Additionally, Solvay launched a PPA-based unidirectional (UD) thermoplastic carbon fiber-based tape to accelerate thermoplastic composite developments in automotive industry.

Their third launch was the new long glass fiber portfolio called Xencor™, which covers PA 6.6., HPPA, PPA, PARA, and PPS long glass fiber products. Xencor™ polyarylamide PARA was selected by Monaco-based Stajvelo to make an all-polymer electric bike. The material fulfills the high structural, mechanical, and aesthetic requirements.

Victrex:

Victrex presented their Victrex HPG™ Gear solutions for powertrain applications. These have good NVH and durability performance. In addition, they announced that their manufacturing facility in Grantsburg, USA, received the IATF 16949 certification. This certification proves that all capabilities are in line with Tier-1 and OEM needs.

What were your experiences on the K fair?

Thanks for reading & till next time!

Greetings,

Herwig Juster

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Polymer Chemistry meets A.I. – Finding and Developing New Polymers with Target Properties in the 21st Century



The thermal conductivity of polymers is a key material property concerning applications such as vehicles electrification (e.g. traction motors and battery modules), communication devices as well as electronics. For instances, implementing a 5G communication standard requires antennas and associated parts being able to sink heat.

While making my research in this context, I came across a publication of Mr. Wu and his team from the Tokyo Institute of Technology in Japan. In their Nature publication entitled “Machine-learning-assisted discovery of polymers with high thermal conductivity using a molecular design algorithm”, they report on the use of big data analytics for the purpose of discovering new compounds and polymers. Their research targeted, in particular, the finding of a higher thermal conductivity Polyimide (PI). PI is often used in communication and sensor devices. For this, machine learning was applied, i.e. computers were allowed to learn from a given data set. In a first step, training of the algorithm is done in the given database. In a next step the trained application looks into a real world database containing several thousand of polymers to find PI and/or other compounds and/or combinations thereof which can fulfill the target requirements. Identification of more than thousand “virtual” polymers could be achieved by applying this methodology. In a next step, the three most promising polymers were selected out of the big pool with the underlying boundary condition of easy synthesis and processing. In the end, all suggested polymers were polyamides: a wholly aromatic polyamide (Figure 1a), an aromatic polyhydrazide (Figure 1b), and an aliphatic–aromatic polyamide (Figure 1c).

Figure 1: Resulting polymers of the molecular design study using machine learning and AI [2].

The suggested polymers were synthesized, cast into films and their thermal conductivities were tested. Commercial PI polymer such as Kapton® (PMDA/ODA*), UPILEX-S (BPDA/p-PDA*1) and UPILEX-R (BPDA/ODA*2) were similarly tested as well. The newly suggested polymers exhibited thermal conductivities up to 0.41 W/mK, 2x higher than their commercial PI counterparts whose thermal conductivities ranged from 0.19 to 0.21 W/mK. Previously, these values have only been reached by adding fillers such as boron nitrides to commercial PI’s.
 

Conclusion

Mr. Wu has shown that the use of machine learning and AI combined and big data analytics can be a very efficient and effective tool for materials design. Polymer chemists and data science work together hand in hand expanding the landscape of how to carry out research in the 21st century.

Thank you for reading!

Best regards,
Herwig Juster

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

[1] https://www.scienceandtechnologyresearchnews.com/successful-application-of-machine-learning-in-the-discovery-of-new-polymers/

[2] S. Wu et al.: Machine-learning-assisted discovery of polymers with high thermal conductivity using a molecular design algorithm (https://www.titech.ac.jp/english/news/2019/044593.html)

* pyromellitic dianhydride and 4,4 –oxydianiline

*1 3, 3, 4, 4 -biphenyltetracarboxylic dianhydride and p-phenylenediamine

*2 3, 3, 4, 4 -biphenyltetracarboxylic dianhydride and 4,4 –oxydianiline

Material Selection Considerations for Electric Vehicles (EV’s) - Thermal Management Systems

In this post, we will have a closer look at the key considerations for thermal management systems used in electric and hybrid cars. This can support an optimal selection of plastic materials.

Traditionally, in internal combustion engine cars a powertrain thermal management and a passenger cabin thermal management system are present. Here, it well understood which type of plastic materials can be used depending on the application requirements.

In EV’s, thermal management systems support additional systems such as:

• Lithium battery: Thermal management systems need to ensure operating temperatures of 40-45°C to maximize battery service life. Composing parts need to retain material properties after 6.000-10.000 hours to ensure safe handling. Thus, precise control of temperature deltas is crucial.

• Traction motor: Thermal management systems need to ensure operating temperature of coils up to 190°C to allow high torque at small size.

• Power electronics: For high power electronic controllers, liquid cooled systems are favored and plastic materials used in housing need to have a thermal conductive role.

• Hybrid EVs: Downsizing of the combustion engine leads to local hot spots, which thermal management systems need to be able to handle.

What are the market trends and emerging needs?

For internal combustion engines increased temperatures due to downsizing of engines are expected. Simultaneously, more and more turbocharging systems need to be used to compensate the missing engine performance. EV’s have a system temperature ranging from 70°C to 80°C. The latter makes polyolefins accessible for thermal management applications.

Furthermore, in battery EV’s an increased aging exposure to water glycol coolant from 3.000 up to 6.000 till 10.000 hours is expected. Thermal management systems need to be active during charging time as well as when the surrounding temperatures are extremely low. Also, when the EV is not operating, temperature is monitored and in case extreme temperatures are reached, thermal management systems have to be activated too.

All this leads to ongoing discussions at the OEM and Tier-1 level on the requirements, which can be summarized as follows:

1) Coolant fluid temperature: ranging from 80°C to 110°C

2) System pressures: can reach up to 3 bar

3) Increased lifetime: up to 10.000 hours

4) Use of dielectric conductive coolant fluids

New design challenges

As mentioned in the beginning, having additional systems such as the battery, traction motor and power electronics for monitoring tasks require higher complexity thermostat valves which need to fulfill a more precise control. Temperature deltas between one battery module and the next module can be as stringent as 1°C.

Since available space for battery module placement is limited, the design of thermal management systems must be compact. Long operation times (during driving, charging and parking) and chemical resistance of water glycol coolant fluids represent another design challenge. One of the most critical challenges is the material strength which includes the weldline strength, especially after long term aging exposure.

Weldlines represent always the weak point of the plastic application, since the connection is weakened due to random orientation of glass fibers in the connection area. In addition, weldline strength is further weakened by water glycol aging. Since we will be dealing with more complex parts, weldlines are unavoidable and need to be taken care of.

Can all this be handled by plastics? - Yes, but only with the proper material selection

Let us summarize the key considerations for our material selection and give suitable polymer examples:

1. Aging temperature: 120-150°C: Polyphenylene sulfide (PPS); 120-135°C: Polyphthalamide (PPA)

2. Aging time: 1.000 – 3.000 hours: PPS and PPA; > 6.000 hours: PPS or PPA based on required temperature.

3. Increased chemical degradation due to different coolants: PPS has best in class chemical resistance.

4. Dimensional stability for sealing tasks: PPS and PPA.

5. Secondary operations such as laser welding: PPA has good laser welding capabilities.

PPS and PPA show promising mechanical behavior even when exposed to high temperatures, water-glycol coolant and long aging time.

Figure 1 shows mechanical data of PPS after exposure to water-glycol coolant (Ryton® R-4-220BL, Solvay). Figure 2 shows the mechanical data of a suitable PPA for water-glycol applications (Amodel® A-1933 HSL, Solvay).



Figure 1: Mechanical data of PPS after exposure to water-glycol coolant (Ryton® R-4-220BL, Solvay).

Figure 2: Mechanical data of a suitable PPA for water-glycol applications (Amodel® A-1933 HSL, Solvay).

PPS and PPA: not all grades are equal

PPS has unbeatable chemical performance due to the benzene sulfide group in the backbone. When exposed to water-glycol coolant, the PPS polymer matrix can withstand long aging times. However, attention needs to be payed to the glass fiber sizing. The same applies to PPA grades as well.

Interfacial adhesion of the polymer to the glass fiber is achieved over the sizing which is coated onto the glass fiber. Standard glass fiber sizings are cleaved when exposed to glycol and thus the mechanical values drop. Therefore, special sizings are used when the final compound is exposed to glycol. When your application is exposed to coolants, using of glycol resistant glass fillers is a must. The compounds shown in Figure 1 and 2 use such glycol resistant glass fiber fillers.

Material recommendations

Table 1 shows a recommendation concerning material selection for EV’s thermal management system based on existing data.

Table 1: Comparison of PPS and PPA for EV thermal management systems

Comparison PPA and PPS for thermal management systems

Overarching, high performance and engineering plastics will find more and more applications in EV thermal management systems.

If you would like support in the material selection of thermal management systems (from polymer to supplier) for ICE and/or EV feel free to get in contact with me. We can discuss your project.

Thanks for reading & till next time!

Greetings,

Herwig Juster

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New to my Find Out About Plastics Blog – check out the start here section
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Literature
[1] https://www.solvay.com/en/brands/ryton-pps#Design-Guidelines
[2] https://www.solvay.com/en/brands/amodel-ppa#Grades

Plastics Part Design: Coefficient of Linear Thermal Expansion (CLTE) of 136 Polymers

Topic of this blog post is the coefficient of linear thermal expansion (CLTE).

CLTE is often presented with the letter “α” and is calculated using the following equation:

α = ΔL / (L0 * ΔT).

L0 is the length of the part at room temperature; ΔL is the length variation of the specimen when it is heated up, and ΔT is the temperature difference between start and end. More details can be found in the standard ASTM D696.

Polymers in applications such as bus bars, which are used in traction motors, battery modules and power electronics, need to pass thermal shock tests. In such tests, metal bars are overmoulded. Thermal cycles between -40°C (1 hour) and +150°C (1 hour) of the overmoulded bars are done. The cycles are counted until cracking of the polymer layer occurs. The similar the CTLE value of both materials and the better the elongation at break of the overmoulded polymer are, the easier the selected material will pass such tests.

In the table below you can find the maximum CLTE of 136 polymers. Furthermore, I added a factor which shows how similar the polymer is to copper in terms of thermal expansion. This is useful for overmoulding of copper elements.



You can add this table to your part design library. Here, you can find some more part design related data: continuous use temperature and thermal conductivity.

Thanks for reading & till next time!

Greetings,
Herwig Juster

Literature:
[1] https://omnexus.specialchem.com/polymer-properties/properties/coefficient-of-linear-thermal-expansion