Fabrication of high-performance green hemp/polylactic acid fibre composites

In this study, a novel compound lamination technique was applied to improve the mechanical properties of hemp fibre-reinforced polylactic acid composites. Polylactic acid fibres were blended with hemp fibres in a specific weight ratio in order to produce needled mats. Then, sections of the needled mat were stacked with several polylactic acid resin layers on either side, then formed hemp/polylactic acid composites through hot-pressing. The tensile and flexural properties of hemp/polylactic acid composites were tested according to ASTM standards. A multi-factor orthogonal analytical approach was adopted to discuss the effect of factors such as the hybrid ratio, forming temperature and pressure on mechanical properties of the developed green composites. The adhesion between the fibres and the matrix in the fracture surfaces and the thermal stability of the produced composites were observed via scanning electron microscopy and thermogravimetric analysis. The component analysis of composites was conducted by infrared spectra for confirming the contribution of polylactic acid. The results showed that adhesion between fibres and matrix was enhanced, as well as mechanical properties also improved, especially the tensile strength and flexural properties were obviously improved by utilizing this novel compounding technique.