Synthesis of Novel Polymers with Controlled Structure by Metallocene-Based Catalysts.

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The following results were obtained from the study of synthesis of novel polymers with controlled Structure by metallocene-based catalysts.1. Stereospecific polymerization using well-defined macromonomers with metallocence catalystsThe polymerizations of macromonomers with homogeneous transition metal catalysts such as metallocene catalysts were described from the viewpoints of not only synthesis of novel polymers but also precision polymerization. Polymerizations of macromonomers with homogeneous catalysts yielded novel stereoregular polymers with long branched chains such as syndiotactic and isotactic graft copolymers. Homopolymerization of the styrene-terminated macromonomer with metallocene catalyst produced a stereoregular multi-branched polymer. Polymorphic behavior of the obtained stereoregular graft copolymer was discussed from the viewpoint of the bulk property.2. Controlled polymerization of vinyl chloride with metallocence catalystsThe Cp^*TiClX_3-MAO (X : Cl and OCH_3) cata … More lysts initiated the polymerization of vinyl chloride, although the molecular polymerization rate was slow. The Cp^*Ti (OCH_3)_3-MAO catalyst in methylene chloride gave high weight polymers in good yields. From elemental analysis and ^1H NMR spectra of the polymers, the Cp^*Ti (OCH_3)_3-MAO catalyst was found to give polymers consisting of repeating regular head-to-tail units without anomalous structure in the main chain.The synthesis of stereoregular polymer is now in progress.3. Polymerization of various vinyl monomer with Ni-based catalystsThe polymerization of methyl methacrylate and t-butyl methacrylate with Ni (acac)2-MAO catalyst was investigated. The polymerization of these monomers was found to control the molecular weight of the polymers. The copolymerization of butadiene and styrene with Ni(acac)_2-MAO catalyst gave the copolymers with s fairly random sequence and high cis-1,4 contents. In relation to Ni-based catalyst, Co (acac)_3-MAO and V (acac)_3-MAO catalysts were found to control the microstructure of poly (butadiene). In addition, Cr (acac)_3-MAO catalyst gave a polymer consisting of 1,2-structure. Less