Abstract
Epoxy and vinyl polyester matrix composites reinforced with cellulose fibre were fabricated and characterized with respect to their flexural, fracture and impact properties. Reinforcement of the polymer by cellulose fibres resulted in a significant increase in the strain at failure, fracture toughness and impact toughness but only a moderate increase in flexural strength and flexural modulus. Moisture absorption of the composites in water was analysed. The kinetics of sorption-diffusion process was investigated and typical kinetic parameters D, k, and M were determined. The use of nano-clay in the composites was effective in imparting a substantial reduction in water permeability due to the tortuous path presented by high aspect ratio clay. Diffusion models for the water uptake behaviour in polymer composites are reviewed. The effect of accelerated exposure to seawater on the flexural and impact properties of composites was also investigated. The salient toughening mechanisms and crack-tip failure processes were identified and discussed in light of observed microstructures.