Preliminary studies were carried out to determine the plasti-
cizer content range for film formulation. Unplasticized BSG films
were brittle and required care in peeling from the casting surface
(Fig. 2A). The incorporation of GLY increased flexibility of BSG films
and made them easier to handle (Fig. 2B).
However, the addition of GLY more than 50% (w/w) (film dry
weight basis) resulted in sticky and wet films. Stickiness of GLY
plasticized films may have resulted from phase separation and dif-
fusion of GLY to the surface of the film (Ghasemlou, Khodaiyan,
Oromiehie, & Yarmand, 2011). The lowest effective GLY con-
centration was 25% (w/w) (film dry weight basis); below this
concentration, the films showed similar behavior to that of films
prepared without GLY.