Effect of neem gum on water sorption, biodegradability and mechanical properties of thermoplastic corn starch-based packaging films

ABSTRACT Cornstarch (CS) is an inexpensive and widely available material that can be easily moulded into thermoplastic starch (TPS) films when mixed with the plasticising agent glycerol (CS- Gly). However, its applications in the packaging sector are limited due to its brittleness and high-water solubility. To enhance the functional characteristics of the CS- Gly films in packaging applications, it was blended with neem gum at the concentrations of 0.3 and 0.9% (w/w). The tensile strength, elongation percentage, water sorption and biodegradability efficacy of the blended cornstarch films (CS-Gly-NG) were analysed. The tensile strength of the blended film improved by 1.1-fold compared with CS-Gly (24.49 ± 0.72 MPa) when the natural gum additive was used at 0.30% (w/w). However, once the natural gum content was raised to 0.9% (w/w), the TS of the film decreased to 21.28 ± 1.75 MPa, whereas the resistance to water solubility improved to a greater extent. Moreover, the biodegradability test showed that the blended films (64-69 wt %) disintegrated more rapidly than the CS-Gly film (17.3%) in a setting akin to the natural environment. Therefore, this blended film (CS-Gly-NG) can be used as an alternative to the commercially available non-biodegradable polyethene films and will have a positive impact on the environment. GRAPHICAL ABSTRACT