Preparation And Properties Analysis Of Poly(ε-caprolacton)/Calcium Sulfate Whisker Composites By In Situ Polymerization

The composites containing Poly(ε-caprolactone)(PCL) and calcium sulfate whisker(CaSO4) were successfully synthesized by in situ polymerization. X-ray diffraction(XRD), Scanning electron microscopy (SEM), Differential scanning calorimetry(DSC), Thermal gravimetric analysis(TGA), Polarizing optical microscope (POM) and gel permeation chromatography(GPC) and were employed to investigate PCL/CaSO4composites.Firstly, SEM observations showed a homogeneous dispersion of calcium sulfate whisker throughout the PCL matrix, and there is a strong interfacial adhesion between fillers and matrix. The incorporation of calcium sulfate whisker did not significantly affect the crystalline structure of PCL, but it can improve the thermal stability of the PCL/CaSO4composites. Meanwhile, the Young’s modules and tensile strength of PCL were improved by calcium sulfate whisker. Nonisothermal melt crystallization of PCL and its composites were studied by DSC and POM in detail. It was found that the presence of calcium sulfate whisker enhances the crystallization of PCL during the nonisothermal melt crystallization processes due to the heterogeneous nucleation effect of calcium sulfate whisker, and the Avrami method and Avrami-Ozawa method well describe the nonisothermal melt crystallization of the pure PCL and its composites.Secondly, we also studied the influence of degradation for the crystallization and mechanical properties of the neat PCL and its composites. With the increasing of degradation time, the crystallization temperature of PCL and its composites increased, which illustrates that degradation enhances the crystallization. At the same time the in vitro degradation would decrease the mechanical properties of the PCL and PCL/CaSO4composites, but the values of Young’s modules and tensile strength of PCL0.5and PCL1.5composites were higher than the pure PCL.