Pattrathip RodsamranRungsinee Sothornvit2025-03-102025-03-102020Songklanakarin Journal of Science and Technology125339510.14456/sjst-psu.2020.592-s2.0-85084037711https://repository.dusit.ac.th//handle/123456789/4772Rice stubble is an agricultural waste with 30.67% yield of cellulose (90.05% _-cellulose content) to be synthesized as carboxymethyl cellulose (CMC). Hemicellulose and lignin were first removed and later rice stubble cellulose was swollen in 30% NaOH and isopropanol as a solvent. Synthesis conditions such as chloroacetic acid content (5Ð7 g in 5 g of alkali cellulose), reaction temperature (50 and 70) and time (180, 270 and 360 min) were investigated to obtain CMC from rice stubble (CMCr). The 7 g of chloroacetic acid at 50 ûC for 180 min provided the best quality of CMCr based on 5 g of rice stubble cellu-lose with degree of substitution, viscosity and purity of 0.64, 36.03 cP and 90.18%, respectively. The presence of carboxymethyl substituents was verified by Fourier transform infrared spectroscopy. CMCr showed commercially low viscosity material and possibly used as a film forming packaging material for food and pharmaceutical products. >© (Publication Year), (publisher Name). All rights reserved.Carboxymethyl celluloseDegree of substitutionPurityRice stubbleWasteArticleScopus