Flexible, High-Density and Water-Resistant Polypropylene/Thermoplastic Elastomer/Inorganic Fillers Composites

This work is aimed at preparing composites from polypropylene (PP) and ethylene-octene copolymer (thermoplastic elastomer - TPE) blends with different fillers (talc, mica, and barium sulfate). Characterizations of ash content, melt flow index, density, flexural and tensile properties, impact resistance, hardness, moisture content, and water absorption are realized. The development of these composites intent to obtain materials with higher density and flexibility than PP, pursuing applications in outdoor, high humidity, or immersion in fluids. Interesting results are obtained, mainly with the use of barium sulfate, which increased the density of PP by 45% with the addition of 12 vol.%. Besides the fillers, the addition of TPE is effective in reducing the stiffness and improving the impact toughness, making possible the filler addition without flexibility losses. In this case, the barium sulfate composites showed flexural modulus close to PP/TPE modulus and impact strength superior to pure PP and PP/TPE blend. The composites moisture content and water absorption also show better results from barium sulfate samples, indicating this filler as a great component to composites that pursues high density, flexibility maintenance, and capable to work in the presence of water.