Synthesis and properties of UV-curable polyester acrylate resins from biodegradable poly(L-lactide) and poly(ε-caprolactone)

摘要

Three kinds of bio-based polyester diols with different chain lengths, including polylactide diol (PLA-D), poly(epsilon-caprolactone) diol (PCL-D) and poly(epsilon-caprolactone-co-lactide) diol (PCLA-D), were synthesized by controlled ring-opening polymerization (ROP). Then UV-curable polyester acrylate resins (PLA-DA, PCL-DA and PCLA-DA) were synthesized by esterification modifying bio-polyols with methacrylic anhydride. Furthermore, the effects of chain length and polymer composition on the UV-curing and mechanical properties of polyester resins were investigated. The viscosity of both PLA-DA and PCL-DA increased sharply with the increase of molecular weight, and PCL can reduce the viscosity of PCLA-DA effectively. In the study of UV-curing kinetics, the increase of viscosity has a negative effect on the conversion and curing of double-bonds. The change trend of gel contents is basically consistent with the curing kinetics. The results of mechanical properties showed that the viscosity and double-bond conversion of the resins had a decisive influence on the mechanical properties of UV-cured materials. It was also found that with the increase of double-bond conversion and cross-linking density, the volume shrinkage of UV-cured materials increased significantly. The results of thermal analysis showed that the thermal stability of PCL-DA was better than that of PLA-DA, and the addition of PCL segments enhanced the thermal stability of PCLA-DA.