E-Glass/Polypropylene Pultruded Nanocomposite: Manufacture, Characterisation, Thermal and Mechanical Properties

The manufacture of continuous fibre-reinforced nanocomposites, E-glass reinforced in a polypropylene (PP) matrix with and without nanoclay, by pultrusion is discussed. Thermal and mechanical characterisation of nanocomposites has been performed and compared with traditional microcomposites. Also, the nanocomposites were characterised by Transmission Electron Microscopy (TEM) and Optical Micrography (OPM). Compressive strength of pultruded polypropylene nanocomposites was improved by improving the yield strength of the surrounding matrix in shear and reducing fibre misalignment in the composite through optimisation of manufacturing process variables. TGA and DSC results show that nanoclay improves thermal stability without any deviation in glass transition temperature and melt temperature. Initially, polypropylene and nanoclay were melt intercalated using a single-screw extruder and the pultruded nanocomposite was fabricated using extruded pre-impregnated (pre-preg) tapes. Compression tests were performed as mandated by ASTM guidelines. OPM was used to examine the failure surfaces. TEM revealed an intercalated morphology. Significant improvements were achieved in compressive strength and compressive modulus with relatively low nanoclay loadings. Mechanical tests were performed for baseline pultruded PP nanocomposite with 0 wt% nanoclay and modified pultruded PP nanocomposite with 3 wt% nanoclay. The tests showed significant improvements in compressive strength (~122%) and shear strength (~60%) in modified pultruded PP nanocomposites in comparison with baseline properties. Uni-axial tensile tests showed a minor increase in tensile strength (~3.4%). Multi-scale simulations of nanoclay/polymer interface behaviour are currently in progress in order to understand the strength enhancement mechanism.