CHARACTERIZATION OF MECHANICAL PROPERTIES OF THERMOPLASTIC NANOCOMPOSITES MANUFACTURED USING PULTRUSION

摘要

In this paper the manufacture of continuous fibre-reinforced thermoplastic nanocomposites is discussed for the case of E-glass reinforced polypropylene (PP) matrix with and without dispersed nanoclay (montmorillonite). The E-Glass/PP nanocomposite was manufactured by the process of pultrusion. Mechanical characterization of nanocomposites were 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 nanocomposite is achieved by improving the yield strength of the surrounding matrix in shear through the dispersion of nanoclay, as indicated by the modified Argon formula, and reducing fiber misalignment in the composite through optimization of manufacturing process variables. 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 and partially exfoliated morphology. Significant improvements were achieved in compressive strength and compressive modulus with relatively low nanoclay loadings. Additional mechanical tests were performed at an independent laboratory for baseline pultruded PP composite without nanoclay and for modified pultruded PP nanocomposite with 3 weight percent nanoclay. These tests confirmed significant improvements in compressive strength (approx 122 percent) and shear strength (approx 60 percent) in modified pultruded PP nanocomposites in comparison with baseline properties. Uniaxial tensile tests showed a small increase in tensile strength (approx 3.4 percent) with 3 wt percent nanoclay loading.