Pang Zhiyi, Huang Shangshi, Li Yi, Zhang Yiyi, Qin Rui
Faculty of Intelligent Manufacturing, Nanning University, Nanning 530200, China.
State Key Laboratory of Power System, Department of Electrical Engineering, Tsinghua University, Beijing 100084, China.
Molecules. 2024 Sep 12;29(18):4329. doi: 10.3390/molecules29184329.
Polyurethane (PU) materials are extensively utilized in power equipment. This paper introduces a comprehensive evaluation method that combines electromagnetics and computational chemistry based on the Density Functional Theory (DFT) to elucidate the impact of external electric fields on the molecular structure of PU during electrical contact. The study focuses on the microstructural and molecular energy changes in the hard (HS) and soft (SS) segments of PU under the influence of an electric field of uniform intensity. Findings indicate that the total energy of HS molecules decreases markedly as the electric field intensity increases, accompanied by a significant rise in both the dipole moment and polarizability. Conversely, the total energy and polarizability of the SS molecules decrease, while the dipole moment experiences a slight increase. Under the influence of a strong electric field, HS molecules tend to stretch towards the extremities of the main chain, leading to structural instability and the cleavage of hydroxyl O-H bonds. Meanwhile, the carbon chain of the SS molecules twists towards the center under the electric field, with no chemical bond rupture observed. At an electric field intensity of 8.227 V/nm, the HOMO-LUMO gap of the HS molecule narrows sharply, signifying a rapid decline in the molecular structure stability, corroborated by infrared spectroscopy analysis. These findings offer theoretical insights and guidance for the modification of PU materials in power equipment applications.
聚氨酯（PU）材料在电力设备中得到广泛应用。本文介绍了一种基于密度泛函理论（DFT）将电磁学与计算化学相结合的综合评估方法，以阐明电接触过程中外部电场对PU分子结构的影响。该研究聚焦于均匀强度电场影响下PU硬段（HS）和软段（SS）的微观结构和分子能量变化。研究结果表明，随着电场强度增加，HS分子的总能量显著降低，同时偶极矩和极化率大幅上升。相反，SS分子的总能量和极化率降低，而偶极矩略有增加。在强电场影响下，HS分子倾向于向主链末端伸展，导致结构不稳定并使羟基O-H键断裂。同时，SS分子的碳链在电场作用下向中心扭曲，未观察到化学键断裂。在电场强度为8.227 V/nm时，HS分子的HOMO-LUMO能隙急剧变窄，表明分子结构稳定性迅速下降，红外光谱分析证实了这一点。这些研究结果为电力设备应用中PU材料的改性提供了理论见解和指导。
