Effects of hydrogen sulfide on the mechanical and thermal properties of cellulose insulation paper: A molecular dynamics simulation
Effects of hydrogen sulfide on the mechanical and thermal properties of cellulose insulation paper: A molecular dynamics simulation
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DOI：
10.1016/j.matchemphys.2019.122153
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发表时间：
2020-01-15
影响因子：
4.6
通讯作者：
Hu, Dong
中科院分区：
文献类型：
--
作者：
Du, Dongyuan;Tang, Chao;Hu, Dong
变压器油纸绝缘系统中含有腐蚀性硫磺引起的绝缘故障是影响该关键设备安全稳定运行的关键因素。迄今为止，人们已经从实验的角度研究了硫腐蚀现象；然而，人们很少关注硫腐蚀的微观机制。在分子动力学模拟的基础上，从氢键、扩散系数、均方位移和力学参数等方面分析了硫化氢含量对纤维素绝缘纸力学性能和热性能的影响。我们的动力学模拟结果表明，纤维素的机械性能随着硫化氢含量的增加而降低。当硫化氢含量为8%时，纤维素的弹性模量下降33.1%，体积模量下降46.4%，剪切模量下降37%，玻璃化转变温度降低83 K。硫化氢含量的增加削弱了纤维素链之间的相互作用，导致链运动增加，从而降低了纤维素的热稳定性。硫化氢分子对纤维素力学性能和热性能的影响主要归因于硫化氢分子与纤维素之间形成许多氢键，破坏了纤维素原有的氢键网络。硫化氢含量高时，纤维素分子之间的范德华力减弱，分子间相互作用降低，纤维素的热稳定性降低。
Insulation faults caused by corrosive sulfur contained in oil-paper insulation systems in transformers are a key factor affecting the safety and stable of operation of this critical equipment. To date, sulfur corrosion phenomena have been studied from an experimental point of view; however, little attention has been paid to the microscale mechanism of sulfur corrosion. On the basis of molecular dynamics simulations, we analyze the effects of hydrogen sulfide content on the mechanical and thermal properties of cellulose insulating paper in terms of hydrogen bonding, diffusion coefficients, mean square displacement, and mechanical parameters. The results of our kinetic simulations show that the mechanical properties of cellulose decrease as the content of hydrogen sulfide increases. At a hydrogen sulfide content of 8%, the elastic modulus of cellulose decreases by 33.1%, the volume modulus decreases by 46.4%, the shear modulus decreases by 37%, and the glass transition temperature decreases by 83 K. An increase of hydrogen sulfide content weakens interactions between cellulose chains, leading to increased chain motion, which thereby reduces the thermal stability of cellulose. The effects of hydrogen sulfide molecules on the mechanical and thermal properties of cellulose are mainly attributed to the formation of many hydrogen bonds between hydrogen sulfide molecules and cellulose, which destroy the original hydrogen bond network of the cellulose. At a high hydrogen sulfide content, van der Waals forces between cellulose molecules are weakened, lowering intermolecular interactions and reducing the thermal stability of the cellulose.