Preparation of the polymer blends
PLA pellets were dried at 105 C for 8 h in an oven to remove
moisture then kept in a desiccator. The natural rubber and triblock
copolymers were cut into small pieces. Polymer blending was
performed using a twin screw extruder (Prism® TSE16TC, Thermo
Electron Corporation, USA) at a temperature of 120, 160 and 160 C
for a feed, middle and die zone, respectively. The screw speed was
150 and 190 rpm for the 1st and 2nd extrusion, respectively. A
2 mm-thick sheet of the polymer blendwas compression molded at
160 C at a pressure of 200 kg/cm2 for 13 min (KT7014, Kao Tieh, Co.,
Taiwan). The specimen was cooled under this pressure for 10 min.