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在纤维素(棉浆粕)的LiCl/N,N-二甲基乙酰胺均相溶液中,以对甲苯磺酰氯(TosCl)为共反应剂,原位活化长链脂肪酸,合成了长链脂肪酸纤维素酯;采用FTIR、1H NMR、XRD和热重分析等手段对产物进行了表征;考察了长链脂肪酸中的碳原子数、反应物配比、反应温度、反应时间等因素对产物取代度的影响。实验结果表明,当n(反应物纤维素葡萄糖苷)∶n(长链脂肪酸)∶n(TosCl)=1∶3∶3、反应温度85℃、反应时间24h时,产物取代度较高;且随长链脂肪酸碳原子数目的增加,产物取代度下降。表征结果表明,与纤维素相比,长链脂肪酸纤维素酯的结晶度下降,使其在有机溶剂中的溶解性增强;酯化反应削弱了纤维素分子间及分子内的作用力,赋予了长链脂肪酸纤维素酯较低的热加工温度。
Long-chain fatty acids were synthesized by in situ activation of tosyl chloride (TosCl) as a co-reactant in a homogeneous solution of cellulose (cotton pulp) LiCl / N, N-dimethylacetamide Cellulose ester. The products were characterized by means of FTIR, 1H NMR, XRD and TG analysis. The effects of carbon number, ratio of reactants, reaction temperature and reaction time on the degree of product substitution Impact. The experimental results showed that when n (reactant cellulose glucoside): n (long chain fatty acid): n (TosCl) = 1: 3: 3, the reaction temperature was 85 ℃ and the reaction time was 24h, As long-chain fatty acid carbon number increases, the degree of product substitution decreased. Characterization results show that, compared with cellulose, long-chain fatty acid esters of cellulose decreased crystallinity, solubility in organic solvents increased; esterification reaction weakens the intermolecular and intramolecular cellulose forces, given Long-chain fatty acid cellulose ester lower thermal processing temperature.