conditioned at 25 C and 58% relative humidity (RH) for 48 h. Films
thicknesses were measured (exactness of 0.001 mm) using
a Digimatic digital external micrometer (Mitutoyo Co., Japan) at ten
different points of the film. For determining film density, samples of
2 2 cm were maintained in a desiccator with phosphorus pentoxide
(0% RH) for 20 days and weighed. Thus, dry matter densities
were calculated by Eq. (1).