Quite the opposite, sponge rubber usually begins with expandable rubber types like EPDM or neoprene. The rubber compound is then supplemented which has a chemical blowing agent, which, upon heating, decomposes and releases gases. This process brings about the expansion of the rubber plus the formation of the sponge-like composition. https://rubber-foam-versus-sponge37048.goabroadblog.com/32907497/how-rubber-foam-versus-sponge-rubber-can-save-you-time-stress-and-money