title: Quantitative analysis of citric acid/sodium hypophosphite modified cotton by HPLC and conductometric titration.
abstract: Isocratic HPLC was used in conjunction with conductometric titration to quantitatively examine the modification of cotton cellulose by citric acid (CA)/sodium hypophosphite (SHP). CA/SHP had been extensively used as a green crosslinking agent for enhancement of cellulose and other carbohydrate polymers without in-depth understanding of the mechanisms. The current study investigated all identifiable secondary polycarboxylic acids from CA decomposition in the CA/SHP-cellulose system under various curing conditions. It was found that CA decomposition was more sensitive to temperature compared with the desirable esterification reaction. Two crosslinking mechanisms, namely ester crosslinking and SHP crosslinking were responsible for the observed improvement in crease resistance of CA/SHP treated cotton fabrics. An oligomer of citraconic acid (CCA) and/or itaconic acid (IA) was identified as a possible contributor to fabric yellowing. Finally, the crease resistance of fabrics correlated strongly with CA preservation in polyol-added CA/SHP crosslinking systems. The dosage of polyol should be held below an inflexion point to keep the undesirable competition against cellulose minimum. The combination of HPLC and conductometric titration was demonstrated to be useful in studying the CA/SHP-cellulose crosslinking system. The findings have implications for better application of CA/SHP in polysaccharide modifications in general.
authors: Key Laboratory of Science & Technology of Eco-Textiles, Ministry of Education, Donghua University, 2999 North Renmin Road, 201620 Shanghai, China; College of Chemistry, Chemical Engineering and Biotechnology, Donghua University, 2999 North Renmin Road, 201620 Shanghai, China.
authors: Tao
authors: T
authors: Ye
authors: Key Laboratory of Science & Technology of Eco-Textiles, Ministry of Education, Donghua University, 2999 North Renmin Road, 201620 Shanghai, China; College of Chemistry, Chemical Engineering and Biotechnology, Donghua University, 2999 North Renmin Road, 201620 Shanghai, China.
authors: Bijia
authors: B
authors: Wang
authors: Key Laboratory of Science & Technology of Eco-Textiles, Ministry of Education, Donghua University, 2999 North Renmin Road, 201620 Shanghai, China; College of Chemistry, Chemical Engineering and Biotechnology, Donghua University, 2999 North Renmin Road, 201620 Shanghai, China.
authors: Jian
authors: J
authors: Liu
authors: Key Laboratory of Science & Technology of Eco-Textiles, Ministry of Education, Donghua University, 2999 North Renmin Road, 201620 Shanghai, China; College of Chemistry, Chemical Engineering and Biotechnology, Donghua University, 2999 North Renmin Road, 201620 Shanghai, China.
authors: Jiangang
authors: J
authors: Chen
authors: Key Laboratory of Science & Technology of Eco-Textiles, Ministry of Education, Donghua University, 2999 North Renmin Road, 201620 Shanghai, China; College of Chemistry, Chemical Engineering and Biotechnology, Donghua University, 2999 North Renmin Road, 201620 Shanghai, China; Department of Textiles, Merchandising & Fashion Design, HECO Building, University of Nebraska-Lincoln, Lincoln, 68583-0802 NE, USA; Department of Biological Systems Engineering and Nebraska Center for Materials and Nanoscience, HECO Building, University of Nebraska-Lincoln, Lincoln, 68583-0802 NE, USA. Electronic address: yyang2@unl.edu.
authors: Yiqi
authors: Y
authors: Yang
keywords: Cellulose; Citric acid; Conductometric titration; Ester crosslinking; HPLC; Sodium hypophosphite