Water Vapor Permeability of Chitosan/Zeolite Composite Films as Affected by Biopolymer and Zeolite Microparticle Concentrations

Abstract

This work evaluated the effect of chitosan and zeolite microparticle concentrations on the water vapor permeability of composite films. In addition, others chemical, thermal, and physical properties of selected films were determined. Chitosan/zeolite composite films were prepared via the solution casting method using chitosans from chitin from common lobster (Panulirus argus) (77 and 275 kDa and ~ 75% of deacetylation degree) and natural zeolite (O = 35–45 µm). Chitosan concentration (1.5–2.0% w/v), zeolite microparticle concentration (0.0–7.0% w/w of chitosan), and molecular weight (MW) of chitosan were selected as factors through an IV optimal response surface design for the best variant of film based on the water vapor permeability (WVP). The WVP increased with an increase in the chitosan and zeolite concentration as well as the MW, being the film obtained from 1.5% (w/v) of chitosan (77 kDa) and 3.5% (w/w of chitosan) of zeolite, the film with the lower WVP. The increase in the chitosan concentration and zeolite addition at 3.5% (w/w of chitosan) decreased the elongation at break, while increased the tensile strength of the films. Water solubility increased with the polymer concentration, while that it was lower (p ≤ 0.05) for composite films with 3.5% (w/w of chitosan) zeolite. The brightness and b* value of the films decreased with the addition of zeolite at 3.5% (w/w of chitosan) for a same polymer concentration. The opacity did not change significantly (p > 0.05), although there was a tendency to decrease with the increase in the chitosan concentration.