Effect of plasticizer and filler on the mechanical and thermal properties of carboxymethyl cellulose films from corn husk

Abstract

In this study, microcrystalline cellulose was extracted from corn husk by a pretreatment process using a sodium hydroxide solution to remove lignin. A hydrogen peroxide and sodium hydroxide solution are then used in the bleaching process, and hydrolysis with sulfuric acid is performed. Carboxymethyl cellulose (CMC) was then synthesized using monochloroacetic acid as a modifier. FTIR analysis confirmed that the microcrystalline cellulose from corn husk had undergone carboxymethylation. Subsequently, carboxymethyl cellulose films were fabricated utilizing the solvent casting method. The study investigated the influence of different additive types (glycerol, propylene glycol, sorbitol, and calcium carbonate) and additive concentrations (0-20% (w/w) based on CMC content) on the mechanical and thermal characteristics of the CMC films. It was observed that the tensile strength and Young's modulus of the CMC film decreased with higher plasticizer content, whereas the elongation at break increased with increasing plasticizer concentration. CMC film with 20% (w/w) of glycerol and propylene glycol showed the highest elongation at break value. On the other hand, CMC film filled with CaCO3 reduces the elongation property but improves the stiffness of the film, as confirmed by the increasing modulus. Adding plasticizer resulted in a decrease in the CMC film's thermal stability.