基于分子动力学的无定形纤维素热力学性质仿真

发布时间：2019-06-22 16:32

【摘要】：为更深入地在微观角度上研究变压器绝缘纸老化机理,利用分子动力学仿真,对不同温度下纤维素无定形区的热力学性质进行了研究。结果表明:纤维素无定形区为各向同性弹性材料,其弹性系数和各模量随着模拟温度的升高均有减小的趋势,与晶区相比,温度对其影响较大;无定形区的刚性随温度升高出现较大减弱;随着温度升高,无定形区内氢键数量减少,并且分子内氢键数目较分子间氢键数目下降快。对比晶区内的氢键数目在相同模拟温度下的极小变化,可知纤维素的老化首先是从纤维素的无定形区内分子间的氢键被破坏开始的。随模拟温度的升高,纤维素分子链运动加剧,但其末端距无明显变化。温度对纤维素无定形区的力学性质和氢键的影响从分子层次上阐明了纤维素绝缘老化实验中结晶度升高及无不定形区先行老化的微观机理。
[Abstract]:In order to study the aging mechanism of transformer insulation paper from a microscopic point of view, the thermodynamic properties of cellulose amorphous region at different temperatures were studied by molecular dynamics simulation. The results show that the amorphous region of cellulose is isotropic elastic material, and its elastic coefficient and modulus decrease with the increase of simulated temperature. Compared with the crystal region, temperature has a greater influence on it; the rigidity of amorphous region decreases greatly with the increase of temperature; with the increase of temperature, the number of hydrogen bonds in amorphous region decreases, and the number of intramolecular hydrogen bonds decreases faster than that of intermolecular hydrogen bonds. Compared with the minimal change of the number of hydrogen bonds in the crystal region at the same simulated temperature, it can be seen that the aging of cellulose begins with the destruction of intermolecular hydrogen bonds in the amorphous region of cellulose. With the increase of simulated temperature, the movement of cellulose molecular chain intensified, but the end distance did not change obviously. The effect of temperature on the mechanical properties and hydrogen bond of cellulose amorphous region expounds the microscopic mechanism of the increase of crystallinity and the advance aging of amorphous zone in cellulose insulation aging experiment at the molecular level.
【作者单位】：国网山东省电力公司电力科学研究院;重庆大学输配电装备及系统安全与新技术国家重点实验室;
【基金】：国家重点基础研究发展计划(973计划)(2011CB209401) 国家创新研究群体基金(51021005)~~
【分类号】：TM21

【参考文献】