Hi All, I'm working on a project that requires a flexible membrane be heated and cooled about 2000 times. During the cooling process, I require the material give off heat for as long a period of time as possible. I figure a phase change material will have the highest heat capacity and give off its latent heat, over an extended period of time, while cooling at it's melting point. So, I'm looking for a phase change material that I can imbed in a thin layer of silicon rubber to form the heat sink part of my membrane. I considered magnesium nitrate hexahydrate (melting point 87 C), but fear that it is too toxic and flammable. The final membrane will be handled extensively and twisted and bent many times over its lifetime. Could someone please give me some more suggestions of what else to try? As many as possible (I may want to mix them to even out the heat transfer over the temp range) Thanks a lot.