Influence of surface modifications of Castor oil fibre on mechanical properties of fibre reinforced Epoxy composites

Abstract

ABSTRACT Castor oil fibre was identified as a new reinforcement for polymer-based composites and can be used in automobile applications. However, the mechanical properties of natural fibres were considerably less when compared with synthetic fibres and can be improved by the surface modification techniques via chemical treatment. In the present work, unidirectional castor oil fibre-reinforced epoxy composites were prepared by hand lay-up process. The tensile, flexural and impact strength properties of composites at 40% volume fractions were tested as per ASTM standards. Mercerised (NaOH) castor-oil fibre-reinforced composite exhibited 28%, 39%, 34%, 25%, 115% of the increment in tensile strength, tensile modulus, flexural strength, flexural modulus, impact strength respectively over untreated composites, the permanganate (KMnO4)-treated castor oil fibre-reinforced composites showed 9%, 35%, 15%, 15%, 85%, respectively. Thus, NaOH chemical treatment gives better results than KMnO4 chemical treatments due to the removal of unwanted material from surface effectively in NaOH treatments. The SEM results showed that the treated composites have a strong interfacial bond regarding untreated composites. Mechanical properties of the composites were predicted by using regression, ANN-single hidden layer, ANN-multi hidden layer models and confirmatory test results shows the reliability of predicted models. The ANN-multi hidden layer model giving the better results.