Synthesis of highly branched copolyether via cationic copolymerization of 3-methyl-3-oxetanemethanol with tetrahydrofuran

摘要

In 1995, Frechet and coworkers first developed the self-condensing vinyl polymerization (SCVP). This new approach to hyperbranched polymers has attributed much attention of polymer chemists. Matyjaszewski and Frechet prepared the hyperbranched polymers by self-condensing atom transfer free radical polymerization. Muller and coworkers reported the self-condensing group transfer polymerization of 2-(2-methyl-1-triethylsiloxy-1-propenyloxy) ethyl methacrylates. In addition, Penczek, Hult and the authors of this work independently performed the self-condensing ring-opening polymerization of 3-ethyl-3-oxetanemethanol and 3-methyl-3-oxetanemethanol obtaining hyperbranched polyethers. In the meantime, Frey and coworkers reported the ring opening multibranching polymerization (ROMP) of glycidol, which also leads to the hyperbranched polymer. In this work, the cationic copolymerization of 3-methyl-3-oxetanemethanol with tetrahydrofuran was implemented. It is interesting that the star-shaped block-copolymer with a hyperbranched core and polytetrahydrofuran arms was finally obtained due to k_(12)k_(11), where k_(12) is the rate constant of the reaction of terminal 3-methyl-3-oxetanemethanol unit with tetrahydrofuran, and k_(11) means the rate constant of homopolymerization of 3-methyl-3-oxetanemethanol.