| 초록 |
As compared with atactic Poly(vinyl alcohol) (PVA), syndiotactic PVA has been known to have different properties due to the increased intermolecular hydrogen bonding between the adjacent chains. To raise the syndiotacticity as well as the molecular weight of PVA, various other vinyl ester monomers have been used. Especially, vinyl pivalate (VPi) is the best among the various vinyl ester monomers in producing syndiotacticity-rich PVA, owing to the strong steric hindrance of the tert-butyl group in VPi. The polymerization temperature is reported to have a paramount effect on the linearity and the molecular weight of polymer. As a rule, the degree of branching is diminished with lowering the polymerization temperature. In this study, a low temperature initiator, 2,2'-azobis(4-methoxy-2,4-dimethylvaleronitrile), which can reduce the polymerization temperature below 10 oC, was selected in solution polymerization of VPi in dimethyl sulfoxide to obtain high molecular weight poly(vinyl pivalate) with higher stereoregularity. The effect of polymerization conditions on the polymerization behavior of VPi was examined.
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