Manufacturing and characterization of sustainable hybrid composites using sisal and hemp fibres as reinforcement of poly (lactic acid) via injection moulding

Natural polymers based composites offers significant advantages over synthetic fibre reinforced petroleum matrix based composites with regard to biodegradability, biocompatibility, design flexibility and sustainability. This work reports for the first time manufacturing of hybrid fibre reinforced biodegradable composites using sisal and hemp fibre with polylactic acid employing melt processing and injection moulding techniques. Granulated sisal and hemp fibres were blended and hybrid composites were manufactured using aliphatic polyester made up of lactic acid (PLA) through extrusion and injection moulding and their performance was evaluated. Experimental results revealed that density, elongation at break and water absorption capacity of hybrid composites were 1.14 ± 0.07 g/cm³, 0.93 ± 0.35% and 1.06 ± 0.18% respectively. The achieved mean tensile strength (46.25 ± 6.75 MPa), Young's modulus (6.1 ± 0.58 GPa) and specific tensile strength (38.86 ± 5.0) of hybrid fibre reinforced PLA composites were improved compared to neat PLA. The flexural strength (94.83 ± 11.21 MPa), flexural modulus (6.04 ± 0.55 GPA) and specific flexural strength (79.76 ± 8.80) of hybrid fibre composites also showed better performance than those of neat PLA. Incorporation of sisal and hemp fibre with polylactide remarkably increased the impact strength of composites. Overall, the hybrid composites demonstrated good performance suggesting that they have great potential for use as an environmentally friendly alternative material in automotive, packaging, electronics, interiors and agricultural applications.