低取代羟丙基纤维素的制备工艺优化探析

Research on the optimizing preparation technology of L-HPC

文章采用液相法制备低取代羟丙基纤维素(L-HPC),设计L 9(34)正交实验以浊度值为间接判定指标讨论并确立了制备L-HPC的最佳碱化温度、碱化时间、碱化质量分数和醚化温度,通过气相色谱(GC)、FT-IR、XRD和偏光显微镜表征了不同醚化程度L-HPC的结构和性能。结果表明,在固定醚化剂环氧丙烷(PO)与纤维素质量比为1.7的情况下,碱化温度20℃、碱化时间2 h、碱化质量分数20%、醚化温度85℃时可以制备得到在碱液中溶解性能相对最优的L-HPC。此外,纤维素经醚化改性后部分羟基基团成功被羟丙基基团取代得到L-HPC,易溶于弱碱,随着醚化程度的加深,L-HPC在碱液中的溶解性提高,但结晶度有所下降,L-HPC膜的力学性能提高。

Using liquid phase method,the paper has prepared thelow-substituted hydroxypropyl cellulose(L-HPC).The optimum alkalinization temperature,alkalinization time,alkalinization concentration and etherification temperature for the preparation of L-HPC were discussed and established by using turbidity value as indirect determination index in an designed L 9(34)orthogonal experiment.The structure and properties of L-HPC with different etherification degrees were characterized by gas chromatography(GC),FT-IR,XRD and polarizing microscope.The results have shown that under the condition that the mass ratio of propylene oxide(PO)to cellulose was 1.7,and when the etherifying agent was fixed,the alkaline temperature was 20℃,the alkaline time was 2 h,the alkaline concentration was 20%,and the etherifying temperature was 85℃,L-HPC with optimal solubility in the alkaline solution could be prepared.In addition,after the cellulose was modified by etherification,some hydroxyl groups were successfully replaced by hydroxypropyl groups to obtain L-HPC,which was easily soluble in weak base.With the deepening of etherification,the solubility of L-HPC in alkali liquor increased,but the crystallinity decreased,and the mechanical properties of L-HPC membrane were improved.