There are four processes to creat foams:
• Mechanical foaming
–Mix air into the resin while in a liquid state
–Plastisols, vinyl esters, urea formaldehydes, phenolics, polyesters
• Chemical foaming
–Foaming agents or blowing agents
–Chemical reaction that forms a gas/vapor
• Physical foaming
–Gas is forced into a liquid or molten resin
–Pressure is released quickly
–Foam is created
• Syntactic foams
–Physically mix in hollow beads
–Beads are usually glass or plastic
–Wide density capability