화학공학소재연구정보센터
Journal of Polymer Science Part A: Polymer Chemistry, Vol.50, No.8, 1547-1555, 2012
Synthesis of fluorine-containing star-shaped poly(vinyl ether)s via arm-linking reactions in living cationic polymerization
Various types of fluorine-containing star-shaped poly(vinyl ether)s were successfully synthesized by crosslinking reactions of living polymers based on living cationic polymerization. Star polymers with fluorinated arm chains were prepared by the reaction between a divinyl ether and living poly(vinyl ether)s with fluorine groups (C4F9, C6F13, and C8F17) at the side chain using cationogen/Et1.5AlCl1.5 in a fluorinated solvent (dichloropentafluoropropanes), giving star-shaped fluorinated polymers in high yields with a relatively narrow molecular weight distribution. The concentration of living polymers for the crosslinking reaction and the molar feed ratio of a bifunctional vinyl ether to living polymers affected the yield and molecular weight of the star polymers. Star polymers with block arms were prepared by a linking reaction of living block copolymers of a fluorinated segment and a nonfluorinated segment. Heteroarm star-shaped polymers containing two- or three-arm species were synthesized using a mixture of different living polymer species for the reaction with a bifunctional vinyl ether. The obtained polymers underwent temperature-induced solubility transitions in various organic solvents, and their concentrated solutions underwent solgel transitions, based on the solubility transition of a thermoresponsive fluorinated segment. Furthermore, a slight amount of fluorine groups were shown to be effective for physical gelation when those were located at the arm ends of a star polymer. (C) 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012