A facile fabrication of polypropylene composites with excellent low-temperature toughness through tuning interfacial area between matrix and rubber dispersion by silica nanoparticles located at the interface

Abstract

In order to fabricate super low-temperature tough polymer composites which can withstand extreme environments, hydrophobic silica nanoparticles were incorporated into polypropylene/ethylene propylene rubber (PP/EPR) blends with the hope to tailor the brittle ductile transition temperature (Tbd). Compared with PP/EPR blends, PP/EPR/SiO2 composites presented much lower Tbd, and Tbd decreased with the increase of EPR content and SiO2 content. It was found that PP/EPR/SiO2 composites could present excellent low-temperature toughness with little rigidity loss. Phase morphology showed that the silica nanoparticles were located at the interface of PP and EPR. It was found that silica nanoparticles at the interface could not only suppress the phase coarsening in PP/EPR/SiO2 composites greatly, but also tailor the shape of rubber particles. A detailed investigation on rubber particle size, interparticle distance and interfacial area indicated that the tremendous drop of Tbd should be ascribed to the increased interfacial area between the matrix and rubber phase due to the decreased size and more irregular shape of rubber particles. As a result, a quantitative correlation between Tbd and interfacial area in PP/EPR/SiO2 composites was established. This study provided a facile approach to fabricate polymer composites with super low-temperature toughness or other functions through tuning the size and shape of rubber domains by adding nanoparticles.