LIVING CATIONIC POLYMERIZATION OF VINYL ETHERS IN THE PRESENCE OF ADDED BASES - RECENT ADVANCES

The living cationic polymerization of vinyl ethers was carried out wit h organoaluminum compounds in the presence of various types of esters and ethers (cyclic and acyclic), to find out the suitable added bases available for the living polymerization. The effects of the basicity a nd steric hindrance of added bases were investigated in detail. On the basis of these results, a fast living polymerization system was reali zed. To synthesize water-soluble polymers such as thermally-induced ph ase separating polymers and polyalcohols with well-defined polymer str ucture, the living polymerization of various vinyl ethers was examined . The aqueous solution of living poly(vinyl ethers) having oxyethylene units exhibited a quite sensitive (Delta T-ps=0.3-0.5 degrees C) and reversible phase separation on heating and cooling. The effects of pol ymer structures (pendant substituent. polymer sequence, molecular weig ht, and MWD) on the phase separation behavior were investigated. PVA a nd block copolymers containing PVA units with a narrow MWD were also p repared via living cationic polymerization of vinyl ethers and a depro tection reaction.