| Budget Amount *help |
¥1,700,000 (Direct Cost: ¥1,700,000)
Fiscal Year 1987: ¥300,000 (Direct Cost: ¥300,000)
Fiscal Year 1986: ¥1,400,000 (Direct Cost: ¥1,400,000)
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| Research Abstract |
For prepatation of block or graft copolymers consisting of varieties of polymer chains by radical polymerization, one of the most promising procedures is polymerization with a polymer-initiator. In this study, monomer-initiators, 2-methacryloyloxyethyl 4,4'-azobis-4-cyanopentanoate (HEMA-azo), p-isopropenyl 4,4'-azobis-4-cyanopentanoate (<alph>-MeSt-azo), 1,1'-azobis-1-methacryloyloxyphenyl-ethane, 2,2'-azobis(methacryloyloxymethyl)propionitrile, and 2,2'-azobis-2-methyl-N-(2-methacryloyloxyethyl)propionamide were synthesized as to prepare the polymer-initaitor by copolymerization with styrene or methyl methacrylate. The content of the initiator unit in the polymer was mainly 0.5-5 mol-%. Initiation rate of the polymer-initiator being determined by scavenging with 1,3,5-triphenylveradzyl seemed to be not greater than that of the corresponding low molecular weight initiator, owing to a lower efficiency.
Although decomposition of the polymer-initiator results in a macroradical and a lower molecular weight fragment leading to unavoidable formation of the homopolymer corresponding to the branch, all the polymer-initiators afforded the mixtures involving 50-70 wt-% of the graft copolymers. HEMA-azo and <alph>-MeSt-azo which were prepared by the reactions of 2-hydroxyethyl methacrylate and p-hydroxy-<alph>-methylstyrene with the azo chloride, respectively, were noted as useful monomer-initiators yielding the polymer-initiator with appropriate decomposition rates. However, the polymer-initiator containing <alph>-MeSt-azo unit is preferable to that containing HEMA-azo unit, because the latter tends to form cross-linked product.
These findings suggest that almost any combination of polymer chains is obtainable by this technique. Structual control of the resulting graft copolymer, chain length of the back bone polymer, nunbmer of the branch, and chain length of the branch, were attained on the basis of standard kinetics of radical polymerization.
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