SYNTHESIS AND THERMAL-PROPERTIES OF POLY(2,2-DIMETHYLTRIMETHYLENE TRAHYDROFURAN)-BLOCK-POLY(2,2-DIMETHYLTRIMETHYLENE CARBONATE)

Alkalimetal salts (Li+, K+) and metal-free salts ((CH3)2N!3S+, Bu4N+) of hydroxytelechelic poly(THF) were used as initiators for the anioni c ring-opening polymerization of 2,2-dimethyltrimethylene carbonate (D TC). With both systems triblock copolymers were obtained with a monomo dal distribution of molecular weights, with one exception. Copolymers with equal length of the poly(DTC) block and increasing molecular weig ht of the initiating block show the following features: (i) no influen ce at low molecular weights of the initiator (M(n)BAR = 650); (ii) pla sticizing effect in the range 1000 < M(n)BAR < 2600; (iii) two phase s ystems at M(n)BAR > 2600. The triblock structure of the copolymers was established by degradation of the poly(THF) middle block under acidic conditions with subsequent H-1-NMR and GPC analysis.