Quite the opposite, sponge rubber frequently starts with expandable rubber styles like EPDM or neoprene. The rubber compound is then supplemented using a chemical blowing agent, which, on heating, decomposes and releases gases. This method results in the enlargement from the rubber plus the formation of a sponge-like composition. Linked:foam https://rubberfoamsheets49260.blogzet.com/the-best-side-of-rubber-foam-sheets-48596700