SYNTHESIS OF BLOCK COPOLYMERS FROM 1-CHLORO-1-OCTYNE AND OTHER ACETYLENES THROUGH THEIR SEQUENTIAL LIVING POLYMERIZATION BY MOOCL4-NORMAL-BU4SN-ETOH

Block copolymerizations of 1-chloro-1-octyne (1-ClO) with several subs tituted acetylenes were examined by means of living polymerization. o- (Trifluoromethyl)phenylacetylene (o-CF3PA), o-(trimethylsilyl)phenylac etylene (o-Me3SiPA), 1-chloro-2-phenylacetylene (I-ClPA), p-butyl-o,o, m,m-tetrafluorophenylacetylene (p-BuF4PA), and tert-butylacetylene (t- BuA) were used as comonomers, and the MoOCl4-n-Bu4Sn-EtOH (mole ratio 1:1:1) catalyst, which is known to effect living polymerization of sub stituted acetylenes, was employed. When o-CF3PA and 1-ClPA were the co monomers in combination with 1-ClO, block copolymers were exclusively obtained in both orders of monomer addition. In the cases of o-Me3SiPA and p-BuF4PA as comonomers, the copolymerizations initiated from 1-Cl O produced block copolymers selectively whereas the homopolymers of o- Me3SiPA and p-BuF4PA also formed if the order of monomer addition was reversed. The pair of I-ClO and t-BuA did not selectively yield block copolymers irrespective of the order of monomer addition. Thus, block copolymerization occurred between 1-ClO and monomers that show high "l ivingness" and close reactivities.