绝缘纸中水分扩散及其对绝缘纸机械性能影响的仿真研究

Simulation of Diffusion of Moisture in Insulation Paper and the Affect on Mechanical Properties of the Paper

利用分子动力学方法绝缘纸中水分的扩散其及影响因素和水分对绝缘纸的机械性能时行了研究。模拟结果表明,不同水分含量的扩散系数受水分与纤维素的相互作用、相对自由体积共同影响。水分的扩散系数与水分和纤维素的相互作用及每个水分子与纤维素形成的氢键数表现出了极强的相关性,而与相对自由体积的相关性并不强。水分的加入使纤维素材料的机械性能在逐步的下降,而塑性增加。随着水分含量的增加,纤维素内聚能密度和溶解度参数均在减小,与纤维素的力学参数的变化规律相似。通过对链间距的分析发现,随着水分的增加,链间距在增大,表明水分弱化了纤维素分子间作用,从而导致了纤维素材料整体的机械性能的下降。

The diffusion behavior of water molecules in amorphous cellulose and their destructive effect on the mechanical properties of cellulose were investigated by molecular dynamics.Both the free volumes of amorphous cells and water molecule-cellulose interaction affect the diffusion of water molecules.The diffusion coefficient of water molecules has an excellent correlation with water molecule-cellulose interaction and the average hydrogen bonds between each water molecule and cellulose;however,this relationship was not apparent between the diffusion coefficient and free volume.It shows a weakening trend in cellulose cohesive energy density,solubility parameters and the mechanical properties with the increase of water content.The higher the water content one amorphous cellulose own,the bigger the interachain distance of cellulose molecules is,which indicates that the intermolecular interaction of cellulose molecules would be weakened by the water greatly.