[Oztamir]

Hello

Im looking for 2 kinds of matherials for a project. One is a liquid that changes to gas in about 40°c or in a burning proccess, and comes back to being liquid in compration. And the second is a polymer that is elastic but tough so the gas can inflate the polymer, and the inflated polymer can take a hit.

Thanks to those who answer. 😀

[Enthalpy]

Welcome, Oztamir!

A polymer that is elastic and resists hits is called an elastomer. Pretty much any elastomer fits what you describe. Natural rubber is more elastic, polyurethane is the shock champion, dozens more exist.

Many liquids boil around 40°C under atmospheric pressure. For instance pentane and cyclopentane would. The difficulty is that they are badly flammable. Fluorocarbons are much safer.
https://en.wikipedia.org/wiki/Perfluorohexane +56°C,
Perfluoromethylcyclopentane +47°C
Perfluorodimethylcyclobutane +45°C

Organofluorine Chemistry: Principles and Commercial Applications
edited by R.E. Banks, B.E. Smart, J.C. Tatlow
page 97 (Googlebook)