Homogeneous Synthesis and Characteri-zation of Quaternized Cellulose Derivatives in NaOH-urea Aqueous Solutions

keywords:sodium hydroxide-urea aqueous solution  quaternized cellulose derivative  homogeneous synthesis

Abstract:Quaternized cellulose (QC) derivatives were synthesized by reacting cellulose with 3-chloro-2-hydroxypropyl trimethyl ammonium chloride (CHPTAC) in an aqueous solution of NaOH-urea. The chemical structures and physical properties of the obtained QC derivatives were characterized using nitrogen content analysis, Fourier transform infrared spectroscopy (FT-IR), 1H-nuclear magnetic resonance (1H-NMR), X-ray diffraction (XRD), and thermal gravity analysis (TGA). The FT-IR and 1H-NMR results confirmed the successful introduction of cationic quaternary ammonium groups into the main chain of cellulose. A series of QC derivatives with the degree of substitution (DS) values ranging from 0.33 to 0.80 were derived by adjusting the molar ratio of CHPTAC to anhydroglucose unit (AGU) of cellulose, concentration of cellulose in the NaOH-urea solution, as well as reaction temperature and time. According to the DS values of the QC derivatives, the optimized synthe-tic conditions were as follows: 25℃ reaction temperature, 3% cellulose in NaOH-urea solution, the molar ratio of etherification agent to glycosidic cellulose of 15∶1, and 12 h reaction time. The TGA and XRD results revealed that the crystalline structure was destroyed during etherification, and the thermal stability of the QC derivatives was lower than that of cellulose.