反应挤出原位制备纤维素马来酸酯

Graft Modification of Cellulose with Maleic Anhydride by In-Situ Reactive Extrusion

以离子液体1-丁基-3-甲基咪唑氯盐([Bmim]C)l作反应介质,采用马来酸酐对纤维素进行原位化学改性。利用双螺杆挤出机的剪切作用来提高纤维素在[Bmim]Cl中的溶解效率,并促进马来酸酐与纤维素的酯化反应。红外光谱(FTIR)结果证明了纤维素马来酸酯的生成,导致纤维素的氢键网络结构破坏,同时也破坏了纤维素的规整度,降低了纤维素的结晶度。热重分析(TGA)结果显示:马来酸酐支链阻碍了纤维素主链的运动,使改性纤维素的热稳定性明显高于未改性纤维素。当马来酸酐与纤维素质量比为0.8、螺杆转速为50 r/min时,改性纤维素在[Bmim]Cl中的溶解度达到20%,是未改性纤维素溶解度的2倍。

Cellulose is chemically modified with maleic anhydride（MA） by in-situ reactive extrusion. 1-N- butyl-3-methylimidazolium chloride （[Bmim]C1） is applied as reaction medium. Owing to the high shear stress of twin-screw extruder, the dissolving efficiency of cellulose in [Bmim]C1 as well as the modification effect of MA is improved effectively. Fourier transform infrared spectrscope （FTIR） results show that the formation of MA side chain in cellulose maleate obviously destroys the regularity of cellulose chains and reduces the crystallinity of cellulose. Thermal gravimetric analysis（TGA） results show that the resistance of cellulose segment motion in the cellulose maleate suppresses the degradation of cellulose in [Bmim]C1 and improves the thermal stability of cellulose maleate. The hydrogen bond network in cellulose maleate is destructed efficiently and intermolecular force of cellulose maleate is decreased with the increase of MA content. As a result, the concentration of cellulose in spinning solution can be up to 20 % when the MA content is 80 % with respect to the weight of cellulose and the screw speed is 50 rpm, which is almost double of the concentration of unmodified cellulose.