摘要
绝缘纸高温裂解时有大量水分生成,为从微观层面研究水分子生成机制及其对绝缘纸的破坏作用,首先以绝缘纸纤维素链的结构单元纤维二糖(Cellobiose)为研究对象,结合Reax FF反应分子动力学模拟方法(Reax FF-MD),模拟绝缘纸高温裂解过程,发现裂解时有大量水分子产生,且水分子数量呈递增趋势,个别时间区间内水分子数量波动明显,存在水分子的消失及再生现象。因不同位置的O原子的活性存在差异,夺H脱H_2O反应分三种情况,即仲醇羟基夺H脱H_2O、醚基O原子夺H脱H_2O和伯醇羟基夺H脱H_2O。最后利用分子动力学模拟水分对纤维素链的破坏作用,发现水分子在纤维素链间自由空隙中局部运动,并与纤维素链上的羟基和醚基O原子结合氢键,既束缚水分子的运动,又破坏纤维素自身的氢键网络。模拟结果和实际实验结论相一致,可为变压器过热故障分析提供借鉴,表明利用分子模拟方法研究绝缘高分子材料老化微观过程及改性研究是一种行之有效的方法。
A large amount of water is produced in the pyrolysis process of insulating paper. ReaxFF molecular dynamics simulation was introduced to study the formation mechanism of H：O molecule and the destruction of moisture on insulating paper. In the pyrolysis process, many H：O molecules were generated. H20 molecules increased with time, but the number of H20 molecules fluctuated obviously in some time intervals due to the disappearance and regeneration of some H20 molecules. The dehydration reaction was divided into three ways because of the 0 atoms in different positions have different activities： H captured by secondary alcohol hydroxyl; H captured by the O atom of ether group; H captured by primary alcohol hydroxyl. Finally, the destruction of moisture on insulating paper was simulated using molecular dynamics. H20 molecules moved in the free space of cellulose chains and marly hydrogen bonds were formed, which bounded the movement of the H20 molecules. The hydrogen bonding network of cellulose was also destroyed. The simulation results coincided well with the experimental conclusions, which may provide references for analysis of overheating fault on transformer. It also showed that it is an effective method to research on the aging process and modification of insulating polymer materials by using molecular simulation method.
出处
《中国电机工程学报》
EI
CSCD
北大核心
2017年第15期4548-4556,共9页
Proceedings of the CSEE
基金
国家自然科学基金项目(51407110
51677110)~~
关键词
绝缘纸
高温裂解
水分
破坏作用
氢键
分子
模拟
insulating paper
pyrolysis
moisture
destruction
hydrogen bond
molecular simulation
