Polylactones, 68

Abstract

Abstract Full Paper: Using Sn( II )2‐ethylhexanoate (SnOct 2 ) in combination with 1,4‐butanediol, 1,1,1‐tris(hydroxymethyl)propane (THMP) or pentaerythritol as initiator systems telechelic polyesters or star‐shaped homopolyesters of ε ‐caprolactone ( ε ‐CL) or L,L ‐lactide (L‐LA) were prepared. These homopolymers were characterized by solution viscosities, 1 H NMR and MALDI‐TOF mass spectra. Using preformed homopolymers as coinitiators star‐shaped polymers having two‐block star arms were obtained. Polymerizations of equimolar mixtures of two monomers yielded star‐shaped polymers with random copolyesters as star arms. The blockiness or randomness of the star arms was characterized by 13 C NMR spectroscopy. Homo‐ and copolymerizations of trimethylene carbonate (TMC) were also studied, but they were plagued by intensive side reactions such as formation of cyclic oligomers, coinitiation with water and crosslinking via transesterification. Star‐shaped polymers having two‐block star arms obtained in this study. magnified image Star‐shaped polymers having two‐block star arms obtained in this study.