ABSTRACT
Probably the most popular polymer-based cushioning is foamed. This is a plastic that has had its density substantially decreased by the creation of cellular structures dispersed through its matrix. For packaging purposes, the dispersion process generally distributes a gas throughout the molten resin which, with heat, creates void "cells" that are allowed to grow to the desired size and then fixed in place by cooling the material. The process is compatible with a number of thermoplastics and can produce rigid or flexible foams .
