Centre de Recherches sur les Macromolécules Végétales, CERMAV-CNRS, BP 53, F-38041 Grenoble Cedex 9, France.
Biomacromolecules. 2013 Sep 9;14(9):3246-55. doi: 10.1021/bm400864z. Epub 2013 Aug 19.
Aqueous suspensions of microfibrillated cellulose obtained by a high pressure homogenization process were freeze-dried after solvent exchange into tert-butanol. The resulting aerogels, which displayed a remarkable open morphology with a surface area reaching 100 m(2)/g, were subjected to a gas-phase esterification with palmitoyl chloride. Under these conditions, variations of the reaction temperature from 100 to 200 °C, of the reaction time from 0.5 to 2 h, and of the initial quantity of reagent, led to the preparation of a library of cellulose palmitates with DS varying from zero to 2.36. These products were characterized by gravimetry, FTIR, and (13)C solid-state NMR spectroscopy. Of special interest were the cellulose palmitate samples of low DS in the range of 0.1-0.4, which corresponded to hydrophobic cellulose microfibrils exclusively esterified at their surface while keeping intact their inner structure.
通过高压匀浆工艺获得的微纤化纤维素的水悬浮液在溶剂交换为叔丁醇后进行冷冻干燥。所得气凝胶具有显著的开放形态，比表面积达到 100 m²/g，然后用棕榈酰氯进行气相酯化。在这些条件下，反应温度从 100 到 200°C、反应时间从 0.5 到 2 小时以及初始试剂用量的变化，导致制备了一系列取代度从 0 到 2.36 的纤维素棕榈酸酯。这些产物通过重量分析、FTIR 和（13）C 固态 NMR 光谱进行了表征。特别有趣的是取代度在 0.1-0.4 范围内的低取代度纤维素棕榈酸酯样品，它们对应于仅在表面酯化的疏水性纤维素微纤丝，而其内部结构保持完整。
