Effects of alkali treatment and elevated temperature on the mechanical properties of bamboo fibre–polyester composites

• Mechanical properties of alkali treated bamboo composites at elevated temperature.
• Sodium hydroxide treatment improved the properties of the bamboo composites.
• 6% NaOH is the optimum level of alkali treatment for bamboo fibre composites.
• Some properties of bamboo composites are enhanced at elevated temperature.
• Properties of treated and untreated composites are same at elevated temperature.

Bamboo fibre reinforced composites are not fully utilised due to the limited understanding on their mechanical characteristics. In this paper, the effects of alkali treatment and elevated temperature on the mechanical properties of bamboo fibre reinforced polyester composites were investigated. Laminates were fabricated using untreated and sodium hydroxide (NaOH) treated (4–8% by weight) randomly oriented bamboo fibres and tested at room and elevated temperature (40, 80 and 120 °C). An improvement in the mechanical properties of the composites was achieved with treatment of the bamboo fibres. An NaOH concentration of 6% was found optimum and resulted in the best mechanical properties. The bending, tensile and compressive strength as well as the stiffness of this composite are 7, 10, 81, and 25%, respectively higher than the untreated composites. When tested up to 80 °C, the flexural and tensile strength are enhanced but the bending stiffness and compressive strength decreased as these latter properties are governed by the behaviour of resin. At 40 and 80 °C, the bond between the untreated fibres and polyester is comparable to that of treated fibres and polyester which resulted in almost same mechanical properties. However, a significant decrease in all mechanical properties was observed for composites tested at 120 °C.