Water resistance.
Water solubility (WS) of films was determined
as the percentage of soluble matter to initial dry matter
of film sample (Tunc and others 2007).
Three randomly selected
specimens fromeach type of film were first dried at 105 ◦C for 24 h
to determine initial drymatter.
Separate films were immersed in 30
mL of distilledwater in a 50-mL beaker. Beakerswere coveredwith
Parafilm “M” wrap (American Natl. Can, Greenwich, Conn.,
U.S.A.) and stored in an environmental chamber at 25 ◦C for 24 h
with occasional stirring.
Undissolved dry matter was determined
by removing the film pieces from the beakers, gently rinsing them
with distilled water, and then oven drying them (105 ◦C, 24 h).
The weight of solubilized matter was calculated by subtracting
the weight of unsolubilized dry matter from the weight of initial
dry matter and expressed as a percentage of the initial dry matter
content.