Physico-mechanical and structural characterization of polyethylene films and thermoplastic pinto bean starch

Abstract

Starch is a biopolymer that is abundant in nature, low-cost, biodegradable, and can be transformed into a thermoplastic material. This work evaluates the films’ physicochemical, thermal, and mechanical properties based on low-density polyethylene (LDPE) and thermoplastic starch (TPS) from beans. Films of four formulations of LDPE with TPS (0, 5, 10, and 15%) were formulated by the extrusion process. The films were evaluated for thickness, color, mechanical properties (tensile strength, Young’s modulus, elongation at break), barrier, and morphological properties. The barrier properties (WVTR and WVP) significantly increased when TPS was incorporated into the films. While the tensile strength and Young’s modulus did not present changes with the addition of TPS, the elongation at break increased from 204.14 to 343.81% with the addition of TPS. Adding TPS to an LDPE matrix modifies its physico-mechanical properties favorably so that it can be applied as a material for flexible packaging.