Structural and Thermal Properties of Agricultural Mulch Films Based on Native and Oxidized Corn Starch Nanocomposites

Abstract

The current need to put an end to the accumulation of synthetic polymer waste during the cultivation and harvest of food has promoted scientific research for the development of biodegradable agricultural mulch films. Native and oxidized thermoplastic corn starch, with and without the addition of natural and modified bentonite (Bent) with an eco‐friendly natural polymer such as chitosan (CS) are proposed as an alternative for this field. The hydrogen‐bonding interactions affecting the structural and thermal properties of the designed films are followed and analyzed by Fourier transform infrared spectroscopy (FTIR), X‐ray diffraction (XRD), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and rheometry. Results indicate that chemical modification carried out onto starch's structure leads to a reduction in the OH polar groups, which affects their films interaction with nano‐clays and glycerol. Besides, nanocomposites which present an intercalated structure demonstrate less effective intercalation when oxidized starch is used as the matrix. Additionally, a higher degree of crystallinity is observed, which could indicate a lower degree of compatibility between polymer and plasticizer. Thermal characterization confirms that the glass transition temperature of plasticized corn starch increases when oxidation is performed due to the decreased compatibility between the plasticizer agent and the oxidized corn starch.

Recent Advances in Thermoplastic Starch Biodegradable Nanocomposites

“…These strategies include Processing techniques [1,[73][74][75][76] and chemical Modification of Nanoclays and/or matrices [67,71,72,[77][78][79]. Several works can be found in the literature dealing with Thermoplastic starch/ clay Nanocomposites mainly for Packaging [78,[80][81][82][83] and agricultural applications [77,84,85].…”

“…Merino et al [84] have developed by twin screw extrusion mulch films based on native and oxidized Thermoplastic starch reinforced with neat and chitosan-modified bentonite. Oxidation of starch was effective in reducing the water absorption of the films, which is one of the limitations of this kind of materials.…”

Renewable cellulosic nanocomposites for food packaging to avoid fossil fuel plastic pollution: a review

“…With the advancement in material science technologies, consumer behavior changes and this had led to the emergence of sustainable packaging materials, which serves as an alternative to conventional synthetic materials (Gutiérrez and Alvarez 2017b;Gaikwad et al 2020). Ongoing research aims to meet the environmental legislation and consumer demands for innovative and sustainable food packaging (Merino et al 2019a(Merino et al , 2019. In comparison with the petroleum-based conventional materials, biopolymers (cellulose, starch, chitosan) are gaining increased attention because of their renewable & cheaper nature (compared to the former) and could be derived from agricultural and marine sources (Rai et al 2019;El-Sayed et al 2020).…”

Biodegradable Carbon-based Ashes/Maize Starch Composite Films for Agricultural Applications

“…The coated films demonstrated to be suitable for agricultural production and the rate of survival and yield of rapeseed increased. Finally, native and oxidized thermoplastic corn starch, with and without the addition of natural and modified bentonite (incorporating an eco-friendly natural polymer, such as chitosan) were proposed as soil cover [16]. The oxidized film evidenced higher degree of crystallinity and less plasticization than the native ones, due to the higher T g .…”