(or cellophane, a cellulose based fiber), polystyrene (or styrofoam), polyurethane (epoxy), polyesters , polymethylmethacrylate PMMA (acrylic or plexiglas), polyvinylchloride (PVC), and polyisobutylene (butyl rubber), Tupperware, Formica plastic laminate, and high-strength Kevlar . Also important are both natural and synthetic rubber as well as the polymerized butadiene , a component of synthetic