Green Composites of Poly(Lactic Acid)/Epoxidized Natural Rubber Filled with Coir Fibers

The aim of this study is to prepare green composites from poly (lactic acid) (PLA) and in-house epoxidized natural rubber (ENR) with coir fibers (CFs). In-house ENR with medium epoxidation degree (about 35 mole% epoxidation) was first prepared via ‘in situ’ epoxidation of natural rubber latex. PLA was melt-mixed with three loadings (10, 20 and 30 wt%) of ENR on a twin-screw extruder, followed by injection molding to observe their mechanical properties (impact strength, tensile strength, Young’s modulus and elongation at break) and thermal stability. The results showed that the addition of the ENR enhanced the impact strength and elongation at break, but deteriorated tensile strength, Young’s modulus and thermal stability of the blends. From mechanical properties consideration, the 90/10 PLA/ENR blend was selected for preparing green composites with different amounts of CFs (5, 10 and 20 phr). It was found that the incorporation of CFs improved tensile strength and Young’s modulus. However, the impact strength, elongation at break and thermal stability of the green composites decreased as compared to those of the neat 90/10 PLA/ENR blend.