Mechanical and thermal properties of polylactic acid/liquid epoxidized natural rubber blends

Abstract

Polylactic acid (PLA) is a potential polymer to be used in various applications due to biodegradable and biocompatible characteristics. However, its brittle nature limits the usage of PLA. In order to improve the brittleness of PLA, liquid epoxidized natural rubber (LENR) was incorporated with PLA. The objective of this study is to investigate the effect of LENR as toughening agent on rigid PLA matrix in term of mechanical and thermal properties. Polylactic acid/liquid epoxidized natural rubber (PLA/LENR) blends were prepared by melt blending method using Brabender internal mixer with temperature 160 ℃, mixing speed of 60 rpm and molded into test samples by compression molding. The LENR content was varied from 0, 5, 10, 15 and 20 wt%. It was found that the addition of LENR increased the impact strength of PLA.10 wt% of LENR showed the optimum impact strength which was 86.05 J/m. However, tensile strength and tensile modulus decreased slightly with increasing of LENR content. The morphology of PLA/LENR blends showed a good dispersion of LENR on PLA matrix at 10 wt% LENR. The differential scanning calorimeter (DSC) showed a gradual drop in melting temperature (Tm) as well as glass transition temperature (Tg) as LENR content increased.