Abstract
Poly(N-vinylcaprolactam)-poly(ethylene glycol) – poly(N-vinylcaprolactam) triblock copolymers were synthesized for the first time by the ATRP of N-vinylcaprolactam (NVCL) initiated from poly(ethylene glycol) (PEG) macroinitiators with 2-chloropropionate groups at both ends and catalyzed by the CuCl/5,7,7,12,14,14-hexamethyl-1,4,8,11-tetraazacyclotetradecane (Me6Cyclam) system. Their polydispersity was larger than 1.8, indicative for a lower control degree of the process, which was ascribed to the slow deactivating behaviour of the catalytic system. The triblock copolymers synthesized displayed thermosensitive behaviour in aqueous solution, undergoing sol – gel transition on the interval 30 - 60°C. It was found that the aggregation (cloud point) and gelation temperatures, as well as the rheological properties of the polymer aqueous solutions depended on the chain length of both PEG and PNVCL blocks. Keywords: N-vinylcaprolactam, poly(ethylene glycol), triblock copolymers, ATRP, thermal gelation