Synthesis and characterization of ABA‐type block copolymers of trimethylene carbonate and ϵ‐caprolactone

Abstract

AbstractThis paper describes the synthesis of a series of ABA‐type triblock copolymers of trimethylene carbonate and ϵ‐caprolactone with various molar ratios and analyses the thermal and mechanical properties of the resulting copolymers. The structures of the triblock copolymers were characterized by 1H and 13C nuclear magnetic resonance spectroscopy, FT‐IR spectroscopy and gel permeation chromatography. Results obtained from the various characterization methods proves the successful synthesis of block copolymers of trimethylene carbonate and ϵ‐caprolactone. The thermal properties of the block copolymers were investigated by differential scanning calorimetry. The Tm and ΔHm values of the copolymers decrease with increasing content of trimethylene carbonate units.Two Tgs were found in the copolymers. Furthermore, both of the Tg values increased with increasing content of trimethylene carbonate units. The mechanical properties of the resulting copolymers were studied by using a tensile tester. The results indicated that the mechanical properties of the block copolymers are related to the molar ratio of trimethylene carbonate and ϵ‐caprolactone in the copolymers, as well as the molecular weights of the resulting copolymers. The block copolymer with a molar composition of 50/50 possessed the highest tensile stress at maximum and modulus of elasticity. Block copolymers possessing different properties could be obtained by adjusting the copolymer compositions. Copyright © 2004 Society of Chemical Industry