What rubber don't melt?

Rubber that doesn't melt is typically referred to as "thermoset rubber." Unlike thermoplastic rubber, which can melt and be reshaped when heated, thermoset rubber undergoes a chemical change during the curing process, making it heat-resistant and stable at high temperatures. Examples include silicone rubber and EPDM (ethylene propylene diene monomer) rubber, which maintain their integrity under heat and do not melt.