What are the main types of foam?

Main types of foam are classified by chemistry and cell structure. By chemistry, main types include polyurethane foam which is most common used in furniture, mattresses, and insulation, available as flexible and rigid, polystyrene foam including expanded polystyrene EPS and extruded polystyrene XPS used in packaging and insulation, polyethylene foam used in packaging and pipe insulation, polypropylene foam, phenolic foam used in insulation, silicone foam used in high temperature gaskets, latex foam made from natural or synthetic rubber used in mattresses and pillows, and metal and ceramic foams for industrial uses. By cell structure, foams are open cell foam where cells are interconnected and soft and breathable, and closed cell foam where cells are sealed and rigid and water resistant. By hardness, there are flexible foams for cushioning and rigid foams for insulation and structural support. So main types are polyurethane, polystyrene, polyethylene, latex, and phenolic foams, divided into open cell and closed cell categories for different applications.