Biodegradable elastic photocured polyesters based on adipic acid, 4-hydroxycinnamic acid and poly(ε-caprolactone) diols

Abstract A novel series of photocurable biodegradable polyesters (CAC/PCL) were synthesized by a high-temperature solution polycondensation of poly(e-caprolactone) (PCL) diols varying molecular weight (MW; 1250, 2000, 3000) and a diacyl chloride of 4,4′-(adipoyldioxy)dicinnamic acid (CAC) as a chain extender derived from adipic acid and 4-hydroxycinnamic acid. The resulting polyesters were photocured by the ultraviolet (UV) light irradiation (λ>280 nm ) in order to prepare elastic polyester with enhanced thermal and mechanical properties. The effects of photocuring by the UV light irradiation on the thermal, tensile and hydrolytic properties of the CAC/PCL were examined. DSC indicated that the melting temperatures and the crystallinities are decreased by the photocuring. The tensile properties of the photocured CAC/PCL films depended on the MW of PCL-diols and photocured time. The CAC/PCL1250 films photocured for 10–60 min exhibited a strength-at-break of 3.1–4.7 MPa and an elongation-at-break of 640–1500%, and recovered very rapidly to the original size from 90 to 300% extension. Enzymatic degradation was performed in the phosphate buffer solution (pH 7.2) with Ps. cepacia lipase at 37 °C and evaluated by the weight loss. Non-photocured CAC/PCL films were degraded very rapidly and the weight loss after 3 h incubation was more than 60%. The weight loss of the photocured films decreased remarkably with increasing the photocuring time due to the increase of cross-linking density, while it increased with increasing the MW of PCL-diols. The photocured CAC/PCL1250 film is promising as a novel biodegradable elastomer for biomedical applications as well as environmental applications.

[1]  H. Mitomo,et al.  Heat resistance of radiation crosslinked poly(ε-caprolactone) , 1998 .

[2]  D. Grijpma,et al.  Crosslinked poly(l-lactide) and poly(ε-caprolactone) , 1996 .

[3]  H. Iwata,et al.  Crosslinking of Poly(L‐lactide) by γ‐Irradiation , 2002 .

[4]  P. Egerton,et al.  Photocycloaddition at excimer sites in a solid polyester of p-phenylenediacrylic acid , 1981 .

[5]  Neil M. Stainton,et al.  Synthesis and characterization of novel biodegradable polymers composed of hydroxycinnamic acid and D,L‐lactic acid , 2001 .

[6]  Manabu Mizutani,et al.  Molecular Design of Photocurable Liquid Biodegradable Copolymers. 1. Synthesis and Photocuring Characteristics , 2000 .

[7]  M. Mochizuki,et al.  Structural Effects on the Biodegradation of Aliphatic Polyesters , 1996 .

[8]  T. Russell,et al.  Small-angle x-ray and light scattering studies of the morphology of blends of poly(ϵ-caprolactone) with poly(vinyl chloride)† , 1976 .

[9]  Minoru Nagata,et al.  Synthesis and Characterization of Photocrosslinkable Biodegradable Polymers Derived from 4-Hydroxycinnamic Acid , 2003 .

[10]  Y. Nakayama,et al.  Preparation and characteristics of photocrosslinkable hydrophilic polymer having cinnamate moiety , 1992 .

[11]  F. Yoshii,et al.  RADIATION CROSSLINKING OF BIODEGRADABLE POLY(BUTYLENE SUCCINATE) AT HIGH TEMPERATURE , 2001 .

[12]  L. Park,et al.  Modification of poly(butylene succinate) with peroxide: Crosslinking, physical and thermal properties, and biodegradation , 2001 .

[13]  J. Kohn,et al.  Photocrosslinked hydrogels based on copolymers of poly(ethylene glycol) and lysine , 1994 .

[14]  R. Stamenova,et al.  Ultraviolet‐induced crosslinking of solid poly(ethylene oxide) , 1997 .

[15]  D. Kaplan,et al.  Biopolymers from Renewable Resources , 1998 .

[16]  R. Kotek,et al.  Thermotropic homopolyesters—VI. A study of polymers based on 4′-hydroxyphenyl-4-hydroxybenzoate , 1984 .

[17]  Manabu Mizutani,et al.  Molecular Design of Photocurable Liquid Biodegradable Copolymers. 2. Synthesis of Coumarin-Derivatized Oligo(methacrylate)s and Photocuring , 2000 .

[18]  D. Haddleton,et al.  Photochemical crosslinking of main-chain liquid-crystalline polymers containing cinnamoyl groups , 1989 .