Search

This study investigated the effect of fibre content, fibre treatment and fibre/matrix interfacial strength on the mechanical properties of industrial hemp fibre reinforced polylactide (PLA) and unsaturated polyester (UPE) composites. Surface treatment of hemp fibres was investigated as a means of improving the fibre/matrix interfacial strength and mechanical properties of hemp fibre reinforced PLA and UPE composites. The fibres were treated with sodium hydroxide, acetic anhydride, maleic anhydride and silane. A combined treatment, sodium hydroxide and silane, was also carried out. The average tensile strength of sodium hydroxide treated fibres (ALK) slightly increased compared with that of untreated fibres, which was believed to be as a result of increased cellulose crystallinity. In contrast, the average tensile strength of acetic anhydride, maleic anhydride and silane treated fibres slightly decreased compared with that of untreated fibres, which was believed to be as a result of decreased cellulose crystallinity. In the case of combined treatment with sodium hydroxide and silane, the average tensile strength of the fibres (ALKSIL) slightly decreased compared with that of alkali treated fibres (ALK), which was also thought to be as a result of decreased cellulose crystallinity. The average Young's modulus and thermal stability of all treated fibres increased compared with untreated fibres. This was considered to be as a result of densification of fibre cell walls due to the removal of non-cellulosic components during treatment. It was also thought that the grafted molecules in cellulose chains of the acetic anhydride, maleic anhydride and silane treated fibres enhanced resistance to thermal degradation. The interfacial shear strength (IFSS) of PLA/hemp fibre samples increased after treatment, except in the case of maleic anhydride treatment. The increase in IFSS could be due to better bonding of PLA with cellulose of treated fibres (except for the maleic anhydride