Effect of comingling techniques on mechanical properties of natural fibre reinforced cross-ply thermoplastic composites

Continuous natural fibre reinforced thermoplastic composite materials not only offer low weight and better strength than short fibre reinforced composites but are also biodegradable and eco-friendly. The impregnation of resin into the reinforcement is considered as a major concern during the fabrication of thermoplastic composites. Therefore, intermediate materials known as comingled fabrics were developed to assist the fabrication of continuous fibre reinforced thermoplastic composites by aligning the polypropylene fibres alongside the reinforcement natural fibres (jute, hemp and flax) using weaving and knitting techniques. Cross-ply composite panels were fabricated using hot press compression moulding method. The novelty of this work is the simplified methodology to develop the comingled fabrics and the effects of comingling on the mechanical properties of composites. The effect of the comingling technique on the tensile, flexural and impact properties of composites is explained in this research work. Knitted comingled composite specimens exhibit superior mechanical properties than woven comingled composite specimens. The experimental results have shown 14%, 7% and 3% increase in tensile strength, 25%, 20% and 13% increase in flexural strength and 37%, 54% and 44% increase in impact strength of knitted comingled specimens of jute, hemp and flax respectively.