Title: Enhancing Dispersion Stability of alpha-1,3-glucan using Adipic Acid Derivatization: A Novel Approach for Industrial Applications

This study focuses on the modification of alpha-1,3-glucan, a naturally occurring polysaccharide, whereby the modification sought to develop a more eco-friendly polysaccharide alternative than synthetic based polymers. To mitigate such environmental challenges posed by conventional plastics, adipic acid-glucan esters coupled via N,N’-carbonyl diimidazole (CDI) were synthesized which improved thermal and colloidal stability of glucan and thus broadened its available uses for various industries. Chemical modifications including sulfation, acetylation and carboxymethylation were discussed and this extended the usefulness of the polysaccharides into pharmaceutical, food technology and biocompatible materials fields. Controlled degrees of substitution (DS) and enhanced colloid stability were obtained through optimization of CDI-to-AGU and AdA-to-CDI ratios. Most importantly, the modified glucan showed the highest zeta potential of –31.27 mV (sample ADG-H) at pH 9 which demonstrated good colloidal stability. Additionally, thermogravimetric assessment indicated that the modified glucans had a higher initial decomposition temperature (IDT) and maximum loss temperature (Tmax) than carboxymethyl glucan, a polyester, which suggests better thermal stability in the presence of glucan esters. FTIR analysis confirmed the presence of an intense carbonyl ester peak at 1735 cm-1 and 13C NMR was found to assist in the recognition of ester formation by the presence of methylene peaks in the 25 ppm and 35 ppm regions corresponding to the adipic acid. The findings of this study indicate that the modified alpha-1,3-glucan has a significant potential to be used for biodegradable, sustainable, and high-performance applications which would be able to replace materials used by industries in the future. These findings further the development of sustainable materials and contribute towards the circular economy objective of reducing plastic waste.