Abstract

Acrodur, aqueous polyacrylic acid solution and dispersion, has been developed as an alternative wood adhesive to phenolic and urea formaldehyde resins. It has many environmental benefits over the conventional thermoset resins that include its non-corrosive nature and non-emission of carcinogenic gases. It has superior tolerance to moisture during composite fabrication and thus drying of the preforms may be minimised or even eliminated contrary to most resins used in natural fibre biocomposites. The aim of this study was to produce optimised hemp fibre reinforced Acrodur resin biocomposites using nonwoven hemp fibre mats by varying Acrodur solution to dispersion ratio, relative humidity, curing time and temperature. The optimised biocomposites gave the best combination of 26.4MPa-cm3/g specific tensile strength and 4.4GPa-cm3/g specific Young’s modulus with 0.94g/cm3density. Thermogravimetric analysis (TGA) and contact angle measurement showed similar thermal stability and increased hydrophobicity of the biocomposites than those of the fibres. From the water immersion test, the path of wicking of water moleculesinto the biocomposites was believed to be rather straight than tortuous and about 43.5% loss of tensile strength and 57.1% loss of Young’s modulus were observed upon 4-week water immersion of the biocomposites.