Synthesis and properties of biodegradable copolymers based on 4,4′-(adipoyldioxy)dicinnamic acid, 1,6-hexanediol, and poly(ethylene glycol)s

4,4'-(Adipoyldioxy)dicinnamic acid (CAC) was synthesized by a condensation of adipoyl chloride and 4-hydroxycinnamic acid. The CAC6 copolymers were prepared by a high-temperature solution polycondensation of a diacyl chloride of CAC, 1,6-hexanediol (6), and poly(ethylene glycol) (PEG) in which the molecular weights of PEG are 1000, 2000, and 8300. Differential scanning calorimetric curves of the copolymers exhibited a glass-transition temperature because of PEG moiety and two melting endotherms (T-m's); the one at the higher T-m was due to CAC6 moiety, and the other at the lower T-m was due to PEG moiety, suggesting that these copolymers are the block type. The incorporation of the PEG component decreased the tensile strength and initial modulus, but increased the elongation extremely. The enzymatic degradation was performed in phosphate buffer solution (pH 7.2) with Ps. cepacia lipase at 37 degreesC. The degradation rate of the copolymers increased significantly with an increasing content of PEG, which was correlated to the water absorption of the copolymers. All copolymers could undergo photocuring by ultraviolet (UV) light irradiation (lambda > 280 nm) at ambient temperature, as examined by UV spectroscopy and solubility. The CAC6/E2000(50/50) film photocured for 3 min exhibited a good elastic property with a maximum tensile strength of 3.7 MPa and maximum elongation of 640%. (C) 2003 Wiley Periodicals, Inc.