184: Synergistic Effect of Chitosan on Mechanical Properties of Soyhull Cellulose Biodegradable Films

Introduction

Plastic has revolutionized modern life with its remarkable properties and making it an essential material in a wide range of industries. However, its non-biodegradability leads to the formation of microplastics and nanoplastics, affecting ecosystems, animals, and humans. This has driven a growing demand for biodegradable and eco-friendly alternatives. Cellulose from agriculture processing byproducts such as soyhulls is a viable option. Soyhulls account for 7–8% of the total soybean mass and constitute enormous byproducts in the soybean processing industry. They contain roughly 50% cellulose. Worldwide soybean production is projected to reach 371 million tons by 2030. Thus, valuable cellulosic material could be envisioned for creating sustainable and functional products from soyhulls. Further, chitosan addition enhances the mechanical, barrier, and UV-blocking properties of the cellulosic films, serving as the filler within the cellulosic matrix.

Methods

Soyhulls cellulosic residue (SCR) was extracted with two-step treatments: potassium hydroxide and sodium chlorite treatments. SCR was solubilized in ZnCl2 solution and was added with 1, 3, 5, and 7% of four chitosan derivatives, namely food, industrial, niger, and mushroom grade. CaCl2 was added as the crosslinking agent, followed by the plasticization with glycerol. Films were cast on a glass plate, framed on a wooden frame, and dried at room temperature for 24 hours. Films were tested for mechanical, barrier, UV blocking, moisture absorption, and biodegradation properties. RStudio 2022.07.01 software was used for Tukey’s HSD test to compare the experimental values at a 95% confidence level.

Results

The incorporation of chitosan into cellulose films significantly enhanced the tensile strength, indicating improved mechanical properties. The water vapor permeability increased slightly due to the hydrophilic nature of films that facilitate moisture transfer. The films partially block the UV radiation and follow the Peleg moisture absorption kinetics. Around 90% degradation of films was noticed in 24% soil moisture within 40 days.

Significance

The incorporation of chitosan into soyhull cellulose films presents a promising innovation in the development of sustainable, biodegradable packaging films with enhanced mechanical, barrier, and UV-blocking properties. The outcome leads to an economical multi-function conservation method for soybean producers in soyhulls management toward improving value and addressing plastic issues.

Authors: Sumi Regmi, Srinivas Janaswamy