Interfacial Effect on Mechanical Properties of Polypropylene Ternary Nanocomposites

Abstract

The matrix/filler interface plays a vital role in mechanical properties of polypropylene (PP)/rigid nanoparticles composites. In general, the use of spherical stearic acid modified CaCO3 (SA-CaCO3) can induce a weak interfacewhich facilitatesparticle debonding from the matrix under loading and reduces plastic resistance, enhancing the toughness of nanocomposites, while the use of polymer-grafted nanoparticles (PGS) can improve the Young’s modulus and yield stress because of strong interfacial binding between particle and matrix. With the objective to simultaneously improve the modulus, yield stress and toughness, the ternary nanocomposites, PP/PGS/CaCO3 (PPSC), were prepared and the morphology, crystallization, and mechanical behavior were investigated and compared to their binary nanocomposites. The results show that Young’s modulus is enhanced as the particle loading, and the yield stress is balanced by two interactions, i.e. the decreasing effect of the weak interface and the enhancement effect of the strong interface. The impact strength of the ternary nanocomposites shows insignificant improvement compared with neat PP, which is attributed to the brittle effect of the weak interface in the particle cluster of SA-CaCO3 and PGS.