Thermoplastic materials useful in the present invention include, for example, polyolefins such as isotactic polypropylene, low density or linear low density polyethylene, medium density polyethylene, high density polyethylene, polybutylene, polyolefin copolymers or terpolymers, such as ethylene/propylene copolymer and blends thereof; ethylene-vinyl acetate copolymers such as ELVAX??? 260, availabl