Effect of glutaraldehyde/glycerol ratios on the properties of chitosan films

Abstract

Chitosan is a biodegradable polymer and could be applied as packaging. To make chitosan more competitive, plasticizers and cross‐linking agents are added in films. The aim of this paper was to obtain and characterize films of chitosan without or with glutaraldehyde (0; 0.99 mg/150 ml) in different concentrations of glycerol (0, 10, 20, and 30%w/w), for improving the properties like tensile resistance and the water vapor permeability. The films were homogeneous, without phase separation, and with a similar chemical structure. The glutaraldehyde makes the chitosan partly hydrophobic, leading to glycerol saturation in samples with glutaraldehyde and 20 or 30% of glycerol. The Principal Component Analysis for the film with glutaraldehyde and 10% of glycerol presented 3.60 g.mm/kPa.day.m² of water vapor permeability and 36.96 MPa of tensile resistance. The use of plasticizer and cross‐linking in combination is promising to make chitosan film more competitive on the market of packaging. PRACTICAL APPLICATIONS: The addition of glutaraldehyde and glycerol was efficient to improve film properties like water vapor permeability and mechanical properties. The chitosan films with glycerol and glutaraldehyde exhibited similar physical and chemical properties to non‐biodegradable polymers from the petrochemical origin and non‐renewable sources. Furthermore, chitosan films with these additives can be applied as packaging, improving the competitiveness of this biopolymer to the market. The technology described in the paper is important for application as secondary or tertiary packaging in the food industry.