Zheng Wei, Xie Jufang, Zhang Jingwen, Tang Chao, Zhao Zhongyong
College of Engineering and Technology, Southwest University Chongqing, Chongqing 400715, China.
Materials (Basel). 2018 Nov 19;11(11):2317. doi: 10.3390/ma11112317.
Polymethylsilsesquioxane (PMSQ) nanoparticles with mass percentages of 0, 2.5, 5.0, 7.2, 9.4 wt %, respectively, were constructed by molecular dynamics methods in this paper. Composite molecular models were established using PMSQ and MPIA (poly-metaphenylene isophthalamide) fiber. The influence of different PMSQ contents on the thermal stability of meta-aramid insulation paper was analyzed from the parameters of mechanical property, interaction energy, and mean square displacement. The results showed that the trend of mechanical properties decreased with the increase of PMSQ content. When the PMSQ content was 2.5 wt %, the mechanical properties of the composited model were the best, which was about 24% higher than that of the unmodified model. From an intermolecular bonding and nonbonding point of view, the energy parameters of composite model with the 2.5 wt % content was better than those of the composite model with other contents. Therefore, it is considered that MPIA can interact better with the 2.5 wt % content PMSQ composite model. When the PMSQ content is 2.5 wt %, the overall chain movement in the composite model is slower than that of the unmodified model, which can effectively inhibit the diffusion movement of the MPIA chain. In general, the thermal stability of composite molecular models MPIA and PMSQ (2.5 wt %) was better improved.
本文采用分子动力学方法构建了质量分数分别为0、2.5、5.0、7.2、9.4 wt%的聚甲基倍半硅氧烷（PMSQ）纳米颗粒。利用PMSQ和间位芳纶（MPIA）纤维建立了复合分子模型。从力学性能、相互作用能和均方位移等参数分析了不同PMSQ含量对间位芳纶绝缘纸热稳定性的影响。结果表明，力学性能随PMSQ含量的增加呈下降趋势。当PMSQ含量为2.5 wt%时，复合模型的力学性能最佳，比未改性模型提高了约24%。从分子间键合和非键合的角度来看，含量为2.5 wt%的复合模型的能量参数优于其他含量的复合模型。因此，认为MPIA与含量为2.5 wt%的PMSQ复合模型的相互作用更好。当PMSQ含量为2.5 wt%时，复合模型中整体链的运动比未改性模型慢，这可以有效抑制MPIA链的扩散运动。总体而言，MPIA与PMSQ（2.5 wt%）复合分子模型的热稳定性得到了较好的提高。
