Effects of polyolefin elastomer grafted with maleic anhydride on the mechanical, thermal, and electrical properties of polypropylene/high-entropy oxide composites

In this study, a series of polypropylene (PP)/high-entropy oxide (HEO)/maleic anhydride-grafted polyolefin elastomer (POE-g-MAH) ternary composites was prepared via melt blending, wherein POE-g-MAH was employed as a compatibilizer at loadings ranging from 0 to 5 phr. The microscopic morphology, crystallization behavior, mechanical properties, electrical properties, and insulation performance of the ternary composites were investigated using scanning electron microscopy (SEM), differential scanning calorimetry (DSC), X-ray diffraction (XRD), dielectric spectroscopy, and volume resistivity measurements. The results revealed an optimal compatibilizer loading at 2 phr, the tensile strength and modulus of the composites reached their peak values of 28.2 ± 3.1 MPa and 481 ± 22 MPa, representing increases of 97% and 39% compared to the 0 phr POE-g-MAH, respectively. Moreover, the degree of crystallinity of PP and the dielectric constant of the composite also reached their maximum values at this loading. The study indicates that the incorporation of POE-g-MAH enhanced the interfacial adhesion between PP and HEO, boosted the interfacial polarization effect, and promoted a better dispersion of HEO in the PP matrix, thereby highlighting its role as a heterogeneous nucleating agent. Furthermore, the impact strength of the composites increased continuously with increasing POE-g-MAH content.