长链纤维素酯在DMAc／LiCl中的均相制备及表征

采用75%乙二胺水溶液对纤维素进行预处理后,以DMAc/LiCl为溶剂,高级脂肪酸为酯化剂,对甲苯磺酰氯为共反应剂在均相状态下合成了纤维素棕榈酸酯和硬脂酸酯。运用红外光谱1、H-NMR、X射线衍射、DSC等手段对产品的结构及性质进行表征,研究了反应时间和反应温度对产物取代度的影响。结果表明,纤维素棕榈酸酯的取代度随反应时间延长和反应温度升高而增大。与纤维素相比,纤维素棕榈酸酯的结晶度下降,而玻璃化转变温度也远低于醋酸纤维素和醋酸丁酸纤维素。纤维素棕榈酸酯和硬脂酸酯分子结构中取代基支链起到了内增塑作用,可改善材料的加工工艺性。

Homogeneous Preparation in DMAc/LiCl and Characterization of Long-Chain Cellulose Esters

Long-Chain cellulose ester has many advantages for application.However,it is hard to be synthesized.In this study,cellulose was pretreated with the solution of 75% 1,2-Ethylenediamine before dissolved in DMAc/LiCl.Then cellulose palmitate and cellulose stearate were prepared with long-chain fatty acids as esterifying agent under homogeneous conditions in presence of toluene-4-sulfonyl chloride.FT-IR,1H-NMR,X-ray diffraction and DSC were applied to characterize the product.The results indicated that the DS increases with reaction temperature and time.The crystallinity of the product deceases compared with cellulose.And the Tg of the product deceases compared with cellulose triacetate and cellulose acetate-butyrate.The introduction of long branched chain acting as internal plasticizer contributes good processability to the materials.