Polypropylene/thermoplastic polyurethane blends: mechanical characterizations, recyclability and sustainable development of thermoplastic materials

Nowadays, various plastic products plays an important and indispensable role in our daily life. However, plastic cannot be essentially decomposed in the nature and thus led to inevitable damage to the environment. The study aims to recycle thermoplastic materials to attain the purposes of recycling, reuse, and sustainability. Polypropylene (PP) and toughening thermoplastic polyurethane (TTPU) are melt-blended for two cycles, which a small amount of compatibilizer (i.e. polypropylene grafted maleic anhydride, PP-g-MA) is added during the process. The morphology and mechanical properties of the PP/MA/TTPU blends are then measured and investigated. SEM images show that without the compatibilizer, TTPU particles demonstrate a dispersive phase in PP matrix. The presence of compatilizer improves the incompatible situation between TTPU and PP. The impact test results have proven that the incorporation of 20 wt% of TTPU and 5 wt% of compatibilizer helps to improve the interphase problem, thereby yielding the impact strength of 63.01 J/g. The tensile strength test results show that the presence of PP compensates for the insufficient rigidity and high production cost of TTPU. The flexural strength test results show that PP with high stiffness synergizes to the softness and flexural performance of TTPU. It is expected that using the secondary recovery process obtains the added value and sustainable use of plastic products, which is helpful to the sustainable development of the earth.