Enhancement of mechanical properties and interfacial adhesion by chemical odification of natural fibre reinforced polypropylene composites

Abstract

Natural fibres are often used for reinforcing thermoplastics, like polypropylene, to manufacture composite materials exhibiting numerous advantages such as high mechanical properties, low density and biodegradability. The mechanical properties of a composite material depend on the nature of the fibres, the nature of the matrix and on the adhesion between fibre and the polymer matrix. The main problem with these natural fibres is their hydrophilic nature, which gives them poor compatibility with the polymer matrix. Therefore, the constituents need to be chemically modified to enhancing adhesion between fibre and polymer matrix. The aim of this work is to improve the interfacial adhesion between the polypropylene matrix and the natural fibre, to improve their mechanical properties. Various chemical treatments with acrylic acid, 4-pentanoic acid, 2,4-pentadienoic acid and 2-methyl-4-pentanoic acid were investigated. The natural fibre reinforced polypropylene composites were processed by compression moulding using a film stack method. The mechanical properties of these modified composites like tensile, flexural and impact strength were analysed and compared. It was found that all these properties are dependent on the amount and kind of chemical treatment. SEM studies revealed that in chemically treated composites the fibres were less inclined to pull out of the matrix which indicates a good interfacial adhesion