Enhancement of toughness and thermal properties of polylactic acid/liquid epoxidized natural rubber/graphene oxide composites

Abstract

Polylactic Acid (PLA) is a biodegradable and biocompatible polymer which has a great potential to be used in various application. However, due to its disadvantages such as poor toughness and brittleness, the usage of PLA is limited. The objective of this work is to improve the toughness and reduce the brittleness of PLA with the addition of liquid epoxidized natural rubber (LENR) and graphene oxide (GO). PLA/LENR/GO blend was prepared by using melt blending method with a speed of 60 rpm under 160 °C for 6 min. The blend was prepared in an internal mixer. The wt% of LENR was varied from 0, 5, 10, 15 and 20 wt% while the GO loading was varied from 0, 1, 1.5, 2 and 2.5 phr. The blended compound then was moulded into test sample using compression moulding. The optimum impact strength was recorded at 10 wt% of LENR which is 86.05 J/m compared to only 40.88 J/m for PLA alone. Addition of 1.5 phr GO showed the highest impact strength which is 153.13 J/m. As the GO loading increased, the degradation temperature (Tdeg) increased accordingly due to the presence of GO which acted to slow down the rate of degradation. Glass transition, melting and cold crystallization temperature of the composite decreased with increasing of GO content.