Effect of electron beam irradiation on the crystallization of silk fibroin fiber-reinforced poly(ε-caprolactone) biocomposites

摘要

In the medical industry, ionizing radiation has attracted increasing interest in recent years for the sterilization of biomedical materials due to its high effectiveness at relatively low cost and simple operation. In the study reported here, silk fibroin (SF) fiber was used to prepare novel reinforced poly(ε-caprolactone) (PCL) biocomposites, and the effect of electron beam irradiation on both non-isothermal and isothermal crystallization kinetics of the SF/PCL biocomposites was investigated. The models of Ozawa treatment, Avrami analysis and regime theory of crystal growth are applicable for describing the non-isothermal and isothermal crystallization kinetics of the irradiated PCL and SF/PCL composites. Compared with non-irradiated PCL and SF/PCL composites, the irradiated specimens exhibit the same crystallization regime (regime II) and similar lateral surface free energy (σ), except for smaller fold surface free energy (σ_e) and work of chain folding (q). The crosslinked PCL network formed in the irradiation process can act as a nucleation agent and accelerate the primary crystallization of PCL. However, the restriction effect of the crosslinked PCL network on the molecular chain mobility will reduce the overall crystallization rate of PCL, and this restriction effect appears stronger in the non-isothermal crystallization process than in the isothermal crystallization process.