X-ray diffraction studies of ABA propylene–ethylene block copolymers

ABA triblock copolymers of propylene and ethylene, where the central block is a random copolymer of ethylene and propylene and the A blocks are either isotactic polypropylene or polyethylene, are described. Structural changes induced by stretching at room and elevated temperatures are reported. WAXS was used to monitor these changes. The results indicate theat block copolymers were synthesized and that different combinations of mechanical properties may be obtained by varying the type and length of the A blocks and adjusting the monomer ratio in the random B block.