Improvement in mechanical properties of grafted polylactic acid composite fibers via hot melt extrusion

The aim of this study was to develop fiber reinforced polylactic acid (PLA) composites via twin screw extrusion with the addition of a compatibilizer. Initial studies were performed to establish the optimum initiator percentage in terms of grafting efficiency between PLA and maleic anhydride (MA). Results show that PLA MA 7 obtained the highest level of grafting efficiency. Subsequent viscometric titration analysis on the compatibilized and uncompatibilized PLA composites showed an increase in the interfacial adhesion for the compatibilized PLA composites. Tensile and flexural properties also confirmed this increase in interfacial adhesion for the compatibilized composites, where the mechanical properties improved considerably, compared with virgin PLA and uncompatibilized composites. Results showed that the mechanical properties increase as PLA-g-MA loading increased. Finally, the rate of compostability of compatibilized composites decreased with the addition of PLA-g-MA. This was attributed to a lack of water absorption due to the bonding of hydroxyl groups on the fibers surface with MA.