Biodegradable, Colorless, and Odorless PLA/PBAT Bioplastics Incorporated with Corn Stover

Abstract

The effective use of agricultural lignocellulose resources in biodegradable bioplastics has become the focus of people’s attention due to the inappropriate disposal of agricultural waste and plastic materials. However, the repulsive smell and uncontrollable color of agricultural lignocellulose-based materials limit their potential to replace common consumer plastics. In this study, when the corn stover (CS) meal enforced the PLA/PBAT matrix using the melt blending method, the lignin and hemicellulose components were shown to substantially impact the color darkening and unsavory odor release for the resultant bioplastic; therefore, an optimized scalable alkaline hydrogen peroxide oxidation that can be performed using traditional pulp and paper production lines was used to modify CS on a large scale (LCS) to enhance the properties of bioplastics fabricated with the PLA/PBAT matrix. As a result, the appearance color and odor character of the bioplastic enforced by LCS have been significantly improved compared to those of natural CS. In addition, the bioplastic (LCS/PLA/PBAT) exhibited good tensile strength (9.7 MPa), flexural strength (18.1 MPa), elongation at break (61.8%), and surface hydrophobicity with a contact angle value of 91.6°, which could meet the requirement of the Chinese National Standard for Packaging. The reinforcing effect of LCS on these performances lay in its rigid structure with a strong fiber network, high content of cellulose crystalline, and hydrophobic nature of lignin after treatment, as proven by FTIR, XRD, and SEM results. Therefore, our bioplastics filled with treated agricultural waste are attractive appearance-wise, economically competitive, and biodegradable, making them a sustainable alternative to common consumer plastics.