2.4.3. Water solubility (WS)
The water solubility ofthe films was defined as the percentage of
dry film matter dissolved after 24 h of immersion in distilled water,
and measured according to the method employed by Gontard,
Guilbert, and Cuq (1992). The dried films from the moisture content
analysis, assigned the initial dry weight (Wi), were immersed
in 30 mL of distilled water and gently stirred for 24 h at 25 ◦C. The
samples were filtered with a pre-weighed desiccated filter paper.
The filter paper containing undissolved fragments of film was dried
at 105 ◦C for 24 h in an oven (Weiss-Gallenkamp, BS model OV-160,
Leicestershire, U.K.). The resulting material was weighed to determine
the final dry weight(Wf). The means of allthe tests conducted
in quadruplicate have been reported. The water solubility (%) was
calculated according to the following equation:
WS (%) = Wi − Wf
Wi
∗ 100