Multi-scale hybrid polyamide 6 composites reinforced with nano-scale clay and micro-scale short glass fibre

Multi-scale reinforcements consisting of clay and short glass fibre (SGF) filled polyamide 6 was prepared by a two-step melt compounding process in a twin-screw extruder. Morphologies of clay in PA matrix were observed via a transmission electron microscope (TEM), while the fracture surfaces of PA/clay/SGF were observed via a scanning electron microscope (SEM). Dynamic mechanical properties and thermal expansion behaviours were measured using a dynamic mechanical analyser (DMA) and a thermal mechanical analyser (TMA). The synergy of multi-scale reinforcements of clay and glass fibre provided better physical properties for polymer–matrix composites (PMCs) than each of individual filler. Clay and glass fibre synergistically improved char formation and reduced the flammability of PA/clay/SGF. Rheological properties of PA/clay/SGF under dynamic and steady shear were evaluated. The Herschel–Bulkley model was applied to predict the effect of two fillers on the viscosity and the yield stress.