反应介质对醋酸纤维素萘甲酰化及其产物性能的影响

Effect of reaction medium on naphthenylation of cellulose acetate and its product properties

为探究反应介质对醋酸纤维素萘甲酰化的影响,首先对二醋酸纤维素(DS=2.45)进行酸水解,再以水解制备的醋酸纤维素(DS=2.01)和1-萘甲酰氯(NpCl)为原料,分别在N,N-二甲基乙酰胺(DMAc)、吡啶中均相合成醋酸纤维素萘甲酸酯(CANp),通过FT-IR及NMR对产物进行结构表征,同时采用X射线衍射、DSC及UV-Vis对产物的结晶行为、热性能和抗紫外性能进行研究.结果表明:以DMAc为反应溶剂所合成的CANp,萘酰基取代度DS_(CANp)为0.52,取代顺序为C_6>C_2>C_3,而以吡啶为反应溶剂所合成的CANp,其DS_(CANp)为0.98,取代顺序为C_2>C_6>C_3;不同化学结构对CANp的结晶行为和热性能影响不大,但对抗紫外性能影响显著,以吡啶为反应溶剂合成的CANp吸光度高达2.67,明显高于以DMAc为反应溶剂所制备的CANp.因此,相对DMAc而言,以吡啶作为反应溶剂具有更好的反应效果.

In order to investigate the effect of reaction medium on the naphthenylation of cellulose acetate, cellulose diac-etate （DS=2.45） was partly deacetylated by acid-catalyzed hydrolysis to cellulose acetate （DS=2.01） and then reacted with 1-naphthoyl chloride （NpCl） to homogeneously synthesize cellulose acetate naphthoate （CANp） in N, N-dimethylacetamide （DMAc） and pyridine, respectively. FTIR and NMR were used to characterize the chemical structure of CANp. Meanwhile, the crystallization behavior, thermal and anti-ultraviolet properties of CANp were studied through X-ray diffraction, DSC and UV-Vis. The results showed that the degree of substitu-tion of naphthoate moiety （DScanp ） of CANp with DMAc as solvent was 0.52, the substitution order was C6 〉 C2 〉 C3,and the DScanp of CANp with pyridine as solvent was 0.98, the substitution order was C2 〉 C6 〉 C3 . The different chemical structures had little effect on the crystallization behavior and thermal property except for the anti-ultraviolet property of CANp. And the absorbance of UV-Vis was up to 2.67 when CANp was prepared in pyridine, which was higher than that in DMAc. Therefore, the reaction with pyridine as solvent was superior to that with DMAc.