Influence of PP-g-MA Compatibilization on the Mechanical and Wear Properties of Polypropylene/Thermoplastic Polyurethane Blends

Polypropylene/thermoplastic polyurethane (PP/TPU) blends of different weight ratios (75/25 and 25/75) were processed by melt blending using a maleic anhydride-grafted polypropylene (PP-g-MA) copolymer as coupling agent. The influence of the amount of the coupling agent (0, 3, 5, 7, 9, 11 phr) on the mechanical, frictional, and wear properties of the blends were characterized through tensile test, three-point bending, dynamic mechanical analysis (DMA), and ball-on-disc wear tests. PP-g-MA was found to be an effective compatibilizer for PP/TPU blends, and mechanical and wear properties of the blends were proved to be strongly impacted by the amount of coupling agent. Tensile strength of the blends tends to increase with increasing the PP-g-MA content and 9 phr is found to be optimal for both concentrations of the blends. Good miscibility of the blends with increasing compatibilizer content was also verified by DMA. From the wear test results, the compatibilizer was found to be more effective in PP75/TPU25 blends, in parallel with the results of the mechanical tests. The PP75/TPU25 blend with 11 phr PP-g-MA content was superior to the other blends. In addition, in this work, a new model based on image processing is proposed that provides accurate and fast wear rate measurement and detailed information of the wear track, especially in heterogeneous materials. Using the model, the homogeneity of the wear track widths was proved to be strongly impacted and improved by the use of a coupling agent