The Effects of Thermoplastic Polyurethane on the Structure and Mechanical Properties of Modified Polypropylene Blends

In this study, a melt-compounding process was used to produce ordinary polypropylene (PP)/thermoplastic polyurethane (TPU) blends and modified impact-resistant polypropylene (MPP)/TPU blends. The influences of TPU on the blending morphology, melting behavior, crystallization behavior, and mechanical properties of these blends were investigated. Differential scanning calorimetry results show that using TPU influences the crystalline and melting behavior of PP/TPU blends, but not of MPP/TPU blends. X-ray diffraction analysis indicated that the presence of TPU neither influences the crystalline structure of PP nor creates new crystalline peaks. The mechanical property test results revealed that PP/TPU blends demonstrate better tensile strength, Young’s modulus, and flexural strength, whereas MPP/TPU blends exhibit higher energy absorption and impact strength. This study is expected to produce optimal products with the preferred continuous and dispersive phases for end users, designing multiple and compatible functionalities of blends.