Preparation and characterization of chitosan/LDPE polymeric blends compatibilized with LDPE-g-MA

Abstract

Chitosan, a polysaccharide, has garnered significant attention due to its eco-friendly, cost-effective, and biodegradable properties. This study explores the chemical modification of chitosan via graft copolymerization with vinyl monomers (methacrylamide and tert-butyl acrylate) in an aqueous medium using ceric ammonium nitrate as an initiator. Three varieties of chitosan and grafted chitosan (10–30%) were combined with low-density polyethylene at various ratios via a twin-screw extruder. To enhance the interfacial interaction between the two materials, maleic anhydride was grafted onto low-density polyethylene and employed as a compatibilizer (5 and 10%). The grafted chitosan was analyzed via fourier transform infrared spectroscopy, gel permeation chromatography, and grafting parameters, such as the percentage of grafting G (%), efficiency E (%), and yield of grafted copolymerization Y (%), were determined. The polymeric blends were produced by twin screw extruder and automatic injection molding machine and subsequently evaluated for their mechanical properties, scanning electron microscopy, thermogravimetric analysis, chemical resistance, and biodegradation studies. Thermal stability analysis of LDPE, Chitosan/LDPE-g-MA/LDPE (RCL), Chitosan-g-methacrylamide/LDPE-g-MA/LDPE (RNCGML), and Chitosan-g-tert-butyl acrylate/LDPE-g-MA/LDPE (RBCGTL) using TGA data shows LDPE retains 99.698% of its mass at 250 °C, compared to Chitosan/LDPE-g-MA/LDPE (RCL)(95.897%), Chitosan-g-methacrylamide/LDPE-g-MA/LDPE (RNCGML) (90.584%), and Chitosan-g-tert-butyl acrylate/LDPE-g-MA/LDPE (RBCGTL) (79.408%). At 400 °C, LDPE retains 97.273% of its mass, while Chitosan/LDPE-g-MA/LDPE (RCL), Chitosan-g-methacrylamide/LDPE-g-MA/LDPE (RNCGML) and Chitosan-g-tert-butyl acrylate/LDPE-g-MA/LDPE (RBCGTL) drop to 79.463%, 82.425%, and 67.815%, respectively. At 500 °C, LDPE degrades to 5.833%, whereas Chitosan/LDPE-g-MA/LDPE (RCL), Chitosan-g-methacrylamide/LDPE-g-MA/LDPE (RNCGML), and RBCGTL retain 8.811%, 10.310%, and 15.053%, respectively, indicating Chitosan-g-tert-butyl acrylate/LDPE-g-MA/LDPE (RBCGTL) superior thermal resistance. Chitosan-g-methacrylamide/LDPE-g-MA/LDPE (RNCGML) exhibits the highest biodegradability, with a 19% weight reduction after 15 days, increasing to 25% after 45 days. Chitosan/LDPE-g-MA/LDPE (RCL) shows a weight loss of 16% and 22%, while Chitosan-g-tert-butyl acrylate/LDPE-g-MA/LDPE (RBCGTL) has the lowest biodegradability at 13% and 19%, respectively, demonstrating superior biodegradability characteristics.