Effect of alkali treatment on tensile properties of short madar fibre reinforced polyester composites

Natural fibre reinforced polymer composites were fabricated with madar fibre as reinforcement and polyester as matrix. The madar fibres were treated with 10% NaOH solution (Mercerization) for surface modification. The composite samples were made with different weight proportions (2.5% to 15%) of both untreated and treated fibre in polyester according to ASTM standards using hand layup technique and tested for tensile properties. From the results, it was seen that there was improvement in the tensile strength of untreated madar fibre reinforced polyester composite to a value of 23.33MPa with increased fibre content up to 10% and with further addition of fibres there was drop in the strength. There was a significant outcome of alkali treatment on tensile strength of composite. The strength of alkali treated madar fibre reinforced composite was increased to a value of 26.23MPa with increase in the treated fibre content up to 15% which is 12.43% higher than that of untreated fibre reinforced polyester composite. There is increase in the modulus of untreated madar fibre reinforced polyester composite to a value of 493.23MPa with increased fibre loading up to 10% and with further fibre loading the value is reduced. It was also depicted that the modulus of treated fibre reinforced composite increased to a value of 444.57MPa with increased fibre loading up to 15% but the value is 9.86% less compared to that of untreated fibre composite. The % elongation of untreated fibre reinforced polyester composite decreased with increase in fibre content and was same with the treated fibre reinforced polyester composite also. (paper)