hi Matthias

what about polyacrylate ?

there are also lots of papers dealin with shape memory elastomers for biomedical applications for example: Shape memory polymers: Past, present and future developmentsReview Article

Progress in Polymer Science, In Press, Corrected Proof, Available online 14 April 2015

Martin D. Hager, Stefan Bode, Christine Weber, Ulrich S. Schubert

I hope it can helps

regards

hi Matthias

what about polyacrylate ?

there are also lots of papers dealin with shape memory elastomers for biomedical applications for example: Shape memory polymers: Past, present and future developmentsReview Article

Progress in Polymer Science, In Press, Corrected Proof, Available online 14 April 2015

Martin D. Hager, Stefan Bode, Christine Weber, Ulrich S. Schubert

I hope it can helps

regards

Hi Matthias,

did you check the Netzsch "Thermal Properties of Polymers" poster?

I was thinking it could be EVA.

PS @ Emmanuel: Saw you at PDDG last week ;)

Thank you Emmanuel for the hint. I will have a look through the review and think about polyacrylate. The isotactic PMMA might be a possibility.

Also thanks to Anja but the problem with EVA is it's crystallinity. I'm looking for an amorphous material.

regards

Matthias

You may try epoxy by curing with suitable jeffamine (Various grades are available)

Yes. polyacrylate will work for the said requirement.

Matthias,

Since we don't know the range of mechanical properties you are looking for nor the application you want to use it for you may try formulations based on the PU chemistry. It is fairly straightforward to tune. However, it has some drawbacks that may not be a concern to you.

Kind regards

PU mechanical properties are easily tunable and definitely rubbery but Tg may be at low temperature.

Just as Emmanual Richaud said, there are thermal responsive shape memory materials that can be tune to transition at desired temperature. 

Poly(methyl acrylate) has the right Tg range (20-30 °C) for what you are looking for.  To improve strength and recovery you can add small quantities of a flexible diacrylate cross-linker.

Tg with PU can be made as high as thermal degradation temperature.

But if you are more familiar with living polymerisation, you may also find a solution with the traditional styrene butadiene copolymers  with that range of Tg. However, the tunability for mechanical properties is not has broad as with the PU chemistry.

You can also find commercial emulsions of copolymers with that range of Tg, you'll just  have to crosslink them with the appropriate initiator.

Please share your preferred choice.

Thank you all for your answers, they are highly appreciated.

At the moment I'm just looking for input for further research but at the moment the final decision can not be made as my spare time is rather limited.

I will have a look at the suggested systems and check what is for me easily available to be prepared for new projects.

regards

Matthias

Polybutylmethacrylate has a Tg of 20°C but in an uncrosslinked form it will be a viskoelastic liquid above Tg and not an elastomer. For this reason you must synthesize the polymer yourself by adding a branching comonomer like ethyleneglycole dimethacrylate (EGDMA). For this purpose you must mix butylmetacrylate with an appropriate amount of EGDMA (e.g. 5-10%), devide the mixture in two portions, add benzoylperoxide to one portion and N,N-dimethyltoluidine to the other (1-2%). Then you mix both portions and polymerisation to a crosslinked material tooks place at RT -  40°C (exothermic). You must cast the mixture in that form which you need. After polymerization thermoplastic shaping is no longer possible.