Thermal and mechanical properties of the polymers synthesized by the sequential polymerization of propylene and 1-hexadecene

The block copolymer of poly(l-hexadecene) (PHD) and polypropylene (PP) was effectively synthesized by the sequential polymerization of propylene and 1-hexadecene by using highly isospecific TiCl3/Cp2Ti(CH3)(2) (Cp = cyclopentadienyl). The block copolymers had two separate melting temperatures of constituent blocks. The modulus of PHD-PP block copolymer was enhanced as the content of sequentially polymerized PP block was increased. The elongation at break showed positive deviation at the intermediate compositions from the simple additive values of constituent homopolymers. Shape memory effect which utilizes the crystalline PHD block as a reversible phase and the crystalline PP block as a fixed structure was examined. (C) 2002 Wiley Periodicals, Inc.