The optimum sodium hydroxide concentration for high strength pla-rice straw composites

Abstract

Most of the recent researches on sodium hydroxide (NaOH) treatment discusses on only the improvement in the properties of natural fibre composites. However, there is a potential in studying the effects of sodium hydroxide treatment even further by identifying the optimum NaOH concentration in order to achieve maximum improvement in the properties of the natural fibre composites. This work reports the development of a composite material derived from both renewable resource and biodegradable material with the emphasis to identify the optimum NaOH treatment condition to achieve maximum improvement in the flexural strength of poly-lactic acid (PLA) reinforced with rice straw (RS) fibres. The RS fibres were treated with different NaOH concentrations (1.25, 2.5, 3.75, 5 and 6.25 mol/L) and the optimum NaOH concentration was 5 mol/L of NaOH where the flexural strength of the PLA/RS fibres were improved by 185%. Thus, it can be concluded that with the optimum NaOH concentration, a strong adhesion between the PLA matrix and the RS fibre which resulted in the improvement in the flexural strength.

Keywords

• poly-lactic acid
• rice straw fibre
• sodium hydroxide
• flexural properties