All of the tested film sheets (were cut into strips
(20 mm 80 mm)) and were equilibrated at 50% RH (relative
humidity) and at 23 C for at least 48 h prior to testing with an
HWS Intelligent Constant Temperature and Humidity Machine
(Ningbo, China). The tensile properties were determined according
to the method described by Chen, Kuo, and Lai (2010), with some
modifications, and were carried out using a TA-XT2i Texture Analyzer
(Stable Microsystems Ltd., UK). Films were mounted between
the tensile grips (A/TG). Initial grip separation was 50 mm and the
crosshead speed was 0.8 mm/s. Tensile strength (MPa) and
elongation at break (E%) were determined. Five repetitions were
performed for each sample.