Film thickness and conditioning
All film samples were cut into seven 2.54 15 cm, one
7 7 cm, and ten 2 2 cm-sized pieces for the measurement
of TS and E, WVP, and WS, respectively. Film thickness
was measured to the nearest 0.01 mm using a hand-held
micrometer (Dial Thickness gauge 7301, Mitutoyo, Japan).
Five thickness measurements were made along the length
of the rectangular film strip and the mean value was used in
the TS calculation for that sample. Similarly, five
measurements were taken on each WVP specimen, one at
the center and four around the perimeter, and the mean
value was used in calculating WVP for that film sample. All
film samples were preconditioned for at least 48 h in a
constant temperature humidity chamber set at 25 1C and
50% RH before testing