SYNTHESIS AND CHARACTERIZATION OF MODEL POLYALKANE-POLY(ETHYLENE OXIDE) BLOCK-COPOLYMERS

We describe the preparation of a new set of amphiphilic block copolyme rs with well-defined molecular weights and block volume fractions. The synthesis of a variety of polyalkane-poly(ethylene oxide) block copol ymers was accomplished by a new polymerization-hydrogenation sequence. Initially, anionic polymerization of either butadiene or isoprene was performed followed by end capping with ethylene oxide. The resulting hydroxyl-terminated polydienes were catalytically hydrogenated to give the corresponding hydroxyl-terminated polyalkanes. These polymeric al cohols were then titrated with potassium naphthalenide to yield the an alogous potassium alkoxides. This type of macroinitiator was employed in the polymerization of ethylene oxide. Seventeen polyalkane-poly(eth ylene oxide) block copolymers were prepared in near quantitative yield s with molecular weights ranging from (1.4 to 8.7) x 10(3) and poly(et hylene oxide) volume fractions ranging from 0.29 to 0.73. These polyme rs are model materials for block copolymer phase behavior studies.