Thermal properties and crystallization behavior of thermoplastic starch/poly(ɛ-caprolactone) composites

TPS/PCL composites were prepared by PCL melt blending with modified corn starch. The structure, thermal properties, morphology and crystallization behavior of these composites were investigated by FTIR, TGA, SEM, XRD and DSC. FTIR confirmed the existence of the interaction between PCL and TPS, whereas TGA showed that the thermal stability was decreased by the addition of TPS. Meanwhile, SEM showed a weak interfacial adhesion with increasing TPS. According to the Avrami theory, TPS functioned as a nucleating agent to improve the crystallinity rate of PCL. However, the XRD analysis revealed that the crystallinity decreased. At the same time, the ΔEa of the composites was higher than those of neat PCL. These changes in values all indicated that mobility constraints existed in the PCL chains with the increasing of TPS, which leaded to a drop in the crystallization ability of PCL.