Polyolefins containing 1,3-disubstituted cyclopentane units as nucleating agents for isotactic polypropylene

Polyolefins containing 1,3-disubstituted cyclopentane units in the main chain have been synthesized by 1,3-polymerization of cyclopentene (PCP), cyclization polymerization of 1,5-hexadiene (PHD), and ring-opening metathesis polymerization of norbornene following hydrogenation of the unsaturated main chain (H-PNB) with various transition metal catalysts. These polyolefins were applied to nucleating agents for isotactic polypropylene, and relationship between the structure of the polyolefins and nucleating effect was studied by DSC, polarized optical microscope, and WAXD. All the polyolefins had an effect of nucleation for isotactic polypropylene (PP). Of the polymeric nucleating agents, H-PNB showed the most effective nucleation. Addition of PCP, which was obtained with a nickel catalyst with diimine ligand, to PP induced β-modification.