氨基磺酸钠对碱/脲体系低温溶解棉纤维的影响

Effect of sodium sulfamate on low temperature dissolution of cotton fiber in alkali/urea system

为改善棉纤维的低温溶解性能,在NaOH/尿素/硫脲/水溶液体系(SUT)中添加氨基磺酸钠。研究氨基磺酸钠用量、预冷温度和搅拌时间对纤维素溶解性能的影响,优化棉纤维溶解体系的组分配比及溶解条件,并测试棉纤维的溶解率。采用扫描电镜、傅里叶红外光谱、X射线衍射和热重等表征、测试再生纤维素的结构和性能。结果表明优化的溶解体系为:NaOH、尿素、硫脲、氨基磺酸钠质量分数分别为7%、6%、6%、0.15%;优化的溶解条件为:预冷温度-12℃,搅拌时间20 min,此时棉纤维溶解率为92.00%,与未添加氨基磺酸钠的溶解体系相比,溶解率增加41.97%(在SUT体系中添加氨基磺酸钠可以提高棉纤维的溶解性);与原棉相比,再生纤维素晶型由Ⅰ型转变为Ⅱ型,热分解温度下降13.37%,说明热稳定性降低。

In order to improve the low-temperature dissolution performance of cotton fibers,sodium sul⁃famate was added to the NaOH/urea/thiourea/aqueous solution system(SUT).The effects of sodium sulfa⁃mate dosage,pre-cooling temperature and stirring time on the solubility of cellulose were studied.The com⁃ponent distribution ratio and dissolution conditions of cotton fiber dissolution system were optimized,and the dissolution rate of cotton fiber was tested.The structure and properties of regenerated cellulose were charac⁃terized and tested by scanning electron microscopy,Fourier transform infrared spectroscopy,X-ray diffraction and thermogravimetry.The results showed that the optimized dissolution system was NaOH,urea,thiourea and sodium sulfamate with mass fraction of 7%,6%,6%and 0.15%,respectively,and the optimized dissolu⁃tion conditions were pre-cooling temperature-12℃and stirring time 20 min,and the dissolution rate of cot⁃ton fibers was 92.00%.Compared with the system without sodium sulfamate,the dissolution rate of cotton fi⁃bers increased by 41.97%.Adding sodium sulfamate to the SUT system could increase the solubility of cotton fibers.Compared with the original cotton fibers,regenerated cellulose crystal transforms from typeⅠtoⅡ,the temperature of thermal decomposition droped 13.37%,indicating thermal stability was lowered.