seeking strain relaxation vs temperature curve for Ultem 1000 or 1010 or 4001

[subsearobot]

Hi All,
I am looking at feasibility of using an interference fit to hold an injection molded part in relation to a steel shaft. This assembly does not need an extremely high retention force, but it must withstand 121degrees C without relaxing below that low retention force.

Does anyone have any information about the strain relaxation of ultem? Will it's relaxation accelerate at that temp, or is ultem impervious until.
What is a good minimum strain (or stress!) to avoid if I want to avoid creep all together?

thanks!

 

[Pud]

Isochronous stress/strain data is useful, but Google only turns up a paid-for paper for Ultem.

Hopefully Sabic should have the info somewhere.

All plastics creep - some more (amorphous) than others (semi-crystalline).

www.tynevalleyplastics.co.uk

Politicians like to panic, they need activity. It is their substitute for achievement.

 

[subsearobot]

I am definitely no polymer scientist, so please correct me- my understanding is that there is potentially a strain limit below which certain polymers do not exhibit strain relaxation. higher temperatures lower said strain limit, but it is predictable.

Dupont publishes charts of strain-relaxation rate vs temp for delrin- hoping to locate same for Ultem. I haven't been able to find it with Sabic but I have only googled for a short while. I was hoping someone here would have it!

I admit, I don't yet grasp the semi-crystalline / amorphous connection very well. Seems to imply PEI is susceptible to creep more than POM?

 

[Pud]

All plastics exhibit creep when strained. Yes, it's time/strain/stress/temperature dependant.

Amorphous plastics are such as polystyrene, polycarbonate, pvc and also Ultem. Semi-crstalline includes nylons, acetal, etc.

All types will creep. I would expect Sabic to have the data - it's probably just finding out who at Sabic has got it squirreled away somewhere.


www.tynevalleyplastics.co.uk

Politicians like to panic, they need activity. It is their substitute for achievement.

 

[mighoser]

Quadrant has a good live chat page for answering technical questions for Ultem (PEI) stock shapes.

https://www.quadrantplastics.com/na-en/?r=1