Abstract
Segmented block copolyetheresters based on poly(butylene terephthalate) and poly(tetramethylene ether glycol) with various hard segment contents were synthesized by equilibrium melt transesteriacation. The copolyetheresters synthesized were found to be true segmented block copolymers from the results of IH-NMR and molting temperature depression data. The copolymers having high hard segment content showed multiple melting behavior, which was thought to be due to melting/recrystallization/ remelting process. The two models for copolyetherester crystallization were examined by checking the relationship between minimum hard segment length for crystallization and melting temperature depression. From the analysis of Flory's melting temperature depression equation. the equilibrium length of crystallite was closely akin to the minimum hard segment length for crystallization calculated on the assumption that all the sequences longer than this minimum length participate in crystallization.
