Sample preparation
The PLA melt blending with NR or ENR were carried out in an internal mixer, (MX 105-D40L50,Chareon TUT Co., Ltd., Thailand) at 170 °C with the rotor speed of 50 rpm. The ratios of thePLA/Rubber were as follows: 100/0, 90/10, 80/20 and 70/30 % by weight. The mixing was proceeded byfirstly plasticized PLA in the internal mixer for 2 minutes and subsequently added quantified rubber to thechamber. The mixing was then carried on for further 13 minutes. The obtained blended plastic was then compressed, at 170 °C and with the pressure of 1500 psi, in a compression molding machine (PR1DW300L350, Chareon TUT Co., Ltd, Thailand) to obtain 2 mm thick plastic sheet for dumbbell shape
sample preparation.