精制棉与硝化工艺对硝化棉含氮量及其分布均匀性的影响

采用北京理工大学自主研发的硝化棉(NC)含氮量及其分布均匀性测试仪,从精制棉聚合度、硝化时间和硝化体系中的HNO3含量三方面考察了硝化棉含氮量及氮量分布均匀性的变化规律。首次把纤维在硝化过程中的膨润程度作为一个指标进行分析。实验结果表明:在可比条件下精制棉的聚合度对所制备的NC含氮量无显著影响,而精制棉的聚合度越小,所制备NC的氮量分布越均匀;随硝化时间延长,NC含氮量先逐渐增大,在硝化时间为30 m in时达到最大值,之后继续延长硝化时间,NC含氮量呈轻微下降趋势;NC的氮量分布指数Dξ值起初随硝化时间延长而减小,在硝化时间为30 m in时取得最小值,之后继续延长硝化时间,Dξ值又逐渐变大;在所研究的范围内,随着硝化体系中HNO3含量的增大,NC的含氮量逐渐增大。硝化体系中HNO3含量过大或过小时,所得NC的氮量分布均匀性都较差,而当HNO3含量为20.8%左右时,所得NC的氮量分布均匀性最好;在考察精制棉聚合度、硝化时间和硝化体系中的HNO3含量三方面因素对硝化结果的影响规律时都发现,纤维的膨润程度是影响NC氮量分布均匀性的最直接原因,纤维膨润程度(平均直径)越大,所得到NC的氮量分布均匀性越好。

Effect of Cotton Linter and Nitrification Conditions on Nitrogen Content and its Distribution Uniformity of Nitrocellulose

The effects of DP of the cotton linter,the nitrification time,and the HNO3 concentration in nitric-sulfuric mixes on the nitrogen content and its distribution uniformity of nitrocellulose were investigated by a test instrument developed by Beijing Institute of Technology.It is the first time that the swelling degree of fibre is used as a analysis indicator.The results show that the DP of cotton linter has no significant effect on the nitrogen content,but the lower the DP is,the more uniform the nitrogen dis...