Plastics not subject to viscoelasticity (cold flow)

[Bcavender]

I have been asked to find a machinable plastic (or dielectric) that will be subject to continuous loading (20 years) that will be subject to stress of appx 100 KPa at a max temp of 64C. While not a high speed or high energy situation, it is a rotating, close clearance application and the material cannot expand from its original dimensions without creating a potential frictional failure that could generate significant heat.

I have read that 'cold flow' over a long time is primarily a problem with thermoplastic polymers 'only', but the information I have been able to pull up so far is very scarce and gives me little confidence about selecting a material. Not being in materials science, my ignorance is probably has me looking in all the wrong places.

Can anyone shed some light about the cold flow being largely a thermoplastic problem and/or recommend a different source of viscoelastic data that I can use to find a plastic NOT subject to this long term phenomenon?

All comments welcome!
Bruce

 

[JBA]

I suggest you go to this company for some initial input for your application

https://www.curbellplastics.com/Research-Solutions/Materials

 

[Bcavender]

JBA,

Thank you for taking the time to link me with the Curbell website. Absolutely the best I have seen for broad comparisons and drill down detail!

Greatly appreciated!
Bruce

 

[Tom.G]

Take a look at Phenolic material, sold as Bakelite and Micarta brands.

 

[ChemAir]

This compounder has a wide variety of different types. It may be worth a look.

From previous work, polyphenylene sulfide, a semicrystalline polymer might be an option. Here's the variety of options for that material.

A lot of physical properties are available for this polymer and others on that site.

 

[Bcavender]

TomG & ChemAir,

Both very good suggestions! I will research both.

Thank you for your assist!

Bruce