Moisture Sorption Characteristics of Chitosan/Polyethylene Oxide Blended Films.

Studies on the moisture sorption characteristics
of chitosan/polyethylene oxide (PEO) blended films have
been carried out at 27 �C for water activity (aw) from 0.1 to
0.9. The sorption data at different aw were used to fit 12
different sorption isotherm models proposed in the literature.
The model constants were determined by linear fitting
of the sorption equations. The ranges of applicability of
water activity for the isotherms reported in the article lie
between 0.11 to 0.44 (monomolecular layer) for the BET
model and between 0.11 to 0.86 (monolayer & multilayer’s)
for Smith, Caurie, Bradley and Oswin. The water
activity for Halsey and Chung & Pfost models lies between
0.44 to 0.86 (multilayer) and 0.33 to 0.86 for Henderson
and Freundlich models and 0.11 to 0.65 for Kuhn, Linear
and Iglesias & Chirife models. The high coefficient of
determination R2 (ranges from 0.82 to 1) confirms the
applicability of the equations employed. The study on the
application of such water activity data of chitosan/PEO
blended films on different model equations will be helpful
in prediction of durability and functional behavior of
moisture sensitive biopolymeric films