The tensile strength, Young's modulus, and elongation at break
of the films were determined following the procedures outlined in
the ASTM methods D882-91 with an average of seven measurements
taken for each film and with at least two films per
formulation. The films were cut into 6-mm by 80-mm strips that
were mounted between the grips of the texture analyzer (TA.XT2i,
Stable Micro Systems, Surrey, England). The initial grip separation
was set at 50 mm and the crosshead speed at 0.5 mm/s. The
tensile strength (s¼force per initial cross-sectional area) and
elongation at break (ε) were determined directly from the
stress–strain curves through the use of OriginPro 8 SR0 v8.0724
software (OriginLab Corporation, USA), and Young's modulus (E)
was obtained from the slope of the initial linear portion of
that curve