2.6. Mechanical properties
The ultimate tensile strength (UTS) and percent elongation (%E)
of the films (140 20 mm2) were determined using a QTS texture
analyzer (CNS Farnell, Essex, UK) according to the ASTM D882-02
(2002) method. Initial grip separation and crosshead speed were
100 mm and 50 mm/min, respectively. UTS was calculated by
dividing the maximum load for breaking the film by the original
minimum cross-sectional area, and %E was calculated by dividing
the film elongation at rupture by the initial gauge length. Before
analysis, the samples were conditioned for 48 h at 55% RH, 25 C.