Heterogeneous method of chitosan film preparation: Effect of multifunctional acid on film properties

ABSTRACT The heterogeneous crosslinking method was applied to chitosan films with citric acid to observe and understand the effect of a multifunctional acid at a low concentration on film properties. Neat and neutralized chitosan films and films containing 15% (w/w) citric acid (denoted as CA films) were characterized by mechanical, water vapor permeability (WVP), and thermogravimetric analysis tests. The CA films displayed a higher tensile strength by 10%, lower WVP by 30%, and higher thermal stability, compared to neutralized films. The crystalline structure converted back from tendon to Type II after the addition of citric acid, as determined by X‐ray diffraction. Neat films displayed a lower water contact angle (72°) compared to neutralized and CA films (78°–79°). The heterogeneous method was also applied to incorporate a plasticizer into a neutralized film to potentially observe the glass transition using dynamic mechanical analysis. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137 , 48648.

Hali tarjima qilinmagan