KINETIC AND THERMODYNAMIC CONTROL IN THE CATIONIC COPOLYMERIZATION OFCYCLIC ETHERS

Cationic copolymerization of tetrahydrofuran with ethylene oxide in he presence of diols proceeds, at the properly chosen conditions, with c omplete conversion of both comonomers and leads to telechelic oligodio ls. These conditions are based on the simultaneous kinetic and thermod ynamic control for two operating mechanisms namely active chain end an d activated monomer mechanism. Kinetics of copolymerization and model reactions were studied. The ratios of rate constants of competing reac tions, governing the copolymer composition, were determined and it was found, that the microstructure of the copolymer can be controlled at low conversion while at higher conversion the kinetics of the competin g parallel reactions is not favourable for the formation of a regular copolymer, in contrast to the previously studied copolymerization of t etrahydrofuran with epichlorohydrin.