Intercollege Graduate Degree Program in Plant Biology, The Pennsylvania State University, University Park, PA 16802, USA.
Carbohydr Polym. 2013 Feb 15;92(2):1809-16. doi: 10.1016/j.carbpol.2012.10.078. Epub 2012 Nov 15.
Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, combustion gas analysis and N(2) adsorption were used to quantify the degree of desulfation of cellulose nanowhiskers (CNWs). CNWs were produced by hydrolyzing cotton cellulose with sulfuric acid or hydrochloric acid. Hydrochloric acid treatment did not result in any cellulose chemical modification. Hydrolysis using H(2)SO(4) introduced sulfate groups onto the cellulose surface. Our results indicate that commercial cotton cellulose as received contained sulfur. The sulfur content of H(2)SO(4)-prepared CNWs was higher than that exhibited by the original cellulose due to the esterification process. Two desulfation methods, acid-catalyzed and solvolytic desulfation, have been explored to remove the sulfate groups. Neither desulfation method examined removed the sulfate groups from H(2)SO(4)-prepared CNWs completely. An estimation of surface sulfate esterification levels was made based on a model of the cellulose structure and available surface area of CNWs. According to these models, more than one third of hydroxyl groups on the surface were substituted by sulfate.
傅里叶变换红外光谱、X 射线光电子能谱、燃烧气体分析和 N2 吸附被用于定量纤维素纳米纤维（CNWs）的脱硫程度。CNWs 是通过硫酸或盐酸水解棉纤维素制备的。盐酸处理没有导致纤维素的任何化学修饰。使用 H2SO4 水解在纤维素表面引入了硫酸盐基团。我们的结果表明，商业棉纤维素在收到时含有硫。由于酯化过程，H2SO4 制备的 CNWs 的硫含量高于原始纤维素。已经探索了两种脱硫方法，酸催化和溶剂解脱硫，以去除硫酸盐基团。这两种脱硫方法都没有完全去除 H2SO4 制备的 CNWs 中的硫酸盐基团。根据纤维素结构和 CNWs 的可用表面积模型，对表面硫酸酯化水平进行了估计。根据这些模型，表面上的三分之一以上的羟基被硫酸盐取代。
