POLYETHYLENE POLY(BUTYL METHACRYLATE-CO-STYRENE) COPOLYMERS INTERPENETRATING-LIKE NETWORKS .1. INFLUENCE OF THE COPOLYMER COMPOSITION ON INTERPENETRATING POLYMER NETWORK PROPERTIES/

IPN-like systems, consisting of low-density polyethylene (PE) and poly [butyl methacrylate (BMA)-co-styrene (S)] copolymer networks, were pre pared in situ by a procedure described in previous papers. The initial PE/copolymer molar ratio was kept equal to 1 for all samples. The ini tial molar BMA/S ratio of the copolymer was varied over a composition range from pure S to pure BMA in order to investigate its influence on IPN properties. The samples obtained were analyzed by DSC; WAXS; tens ile mechanical, dynamic-mechanical, and impact tests; swelling in CCI4 ; and by some optical and electronic observations. The materials, beca me more and more brittle after undergoing mechanical and impact tests, even in the rubbery state, with increasing copolymer BMA content. The morphology consisted of a two-phase system. Good optical properties w ere obtained for the transparent specimens at relatively high BMA mola r contents in the copolymer (70-80% BMA). Reversible changes of the op tical properties were induced by temperature variations. A matching/mi smatching of the refractive indexes of PE and the copolymer was found to be the cause of the optical behavior of these materials. Work is in progress to improve the mechanical behavior of these systems.