SYNTHESIS AND CHARACTERIZATION OF STYRENE-N-BUTYL MALEIMIDE COPOLYMERS USING INIFERTERS CONTAINING THIYL END-GROUPS

The radical homopolymerization of styrene or copolymerization of styre ne (S) with N-butyl maleimide (I) initiated by tetraethylthiuram disul fide was used to prepare macroinitiators having thiyl end groups. The S-I copolymers from the feeds containing 30-70 mol % I showed approxim ately alternating composition. The rate of copolymerization and molecu lar weights decreased with increasing maleimide derivative concentrati on in the feed; homopolymerization of I alone did not proceed. The mac roinitiators served for synthesis of further S-I copolymers. Using pol ystyrene macroinitiator and the S-I copolymer with thiyl end groups in the polymerization of S-I mixture and styrene, respectively, the copo lymers containing blocks of both polystyrene and alternating S-I copol ymer were obtained. The copolymerization of S-I mixture initiated with the S-I copolymer bearing thiyl end groups led to the extension of ma croinitiator chains by the blocks of alternating copolymer. The presen ce of the blocks in the polymer products was corroborated using elemen tal analysis, size exclusion chromatography, and differential scanning calorimetry. (C) 1998 John Wiley & Sons, Inc.