纳米二氧化硅掺杂低密度聚乙烯微观特性的分子模拟
发布时间：2018-11-02 16:44
【摘要】：为研究纳米二氧化硅掺杂低密度聚乙烯体系的玻璃转化温度(Tg)、聚乙烯链的均方位移以及水分子在体系中的扩散系数,通过分子动力学(MD)模拟方法构建了低密度聚乙烯(LDPE)无定形区、纳米二氧化硅以及水分的复合模拟模型。结果表明:水分会降低复合体系的玻璃转化温度;纳米二氧化硅的加入增强了复合模型的热稳定性能,提升了复合体系的玻璃转化转变温度,削弱了聚乙烯分子在复合体系内的链运动;水分子的扩散系数随着温度的升高而增大,纳米二氧化硅的添加会在一定程度上降低水分子在体系中的扩散系数;当温度为300 K左右时,水分子会通过分子间的氢键作用发生局部团聚,而温度的升高会打破邻近水分子间的氢键作用。研究结果可为低密度聚乙烯的热老化试验研究提供有益参考。
[Abstract]:In order to study the mean square shift of (Tg), polyethylene chain and the diffusion coefficient of water molecules in the system, the glass transition temperature of nano-silica doped low density polyethylene (LDPE) system was studied. The complex simulation model of amorphous region, nano-silica and moisture of low density polyethylene (LDPE) (LDPE) was constructed by molecular dynamics (MD) simulation method. The results show that the glass transition temperature of the composite system can be reduced by moisture. The addition of nano-silica enhances the thermal stability of the composite model, raises the glass transition temperature of the composite system, and weakens the chain movement of polyethylene molecules in the composite system. The diffusion coefficient of water molecules increases with the increase of temperature. The addition of nano-silica will reduce the diffusion coefficient of water molecules in the system to a certain extent. When the temperature is about 300K, the water molecules will reunite locally through the hydrogen bond interaction between the molecules, and the increase of temperature will break the hydrogen bond interaction between the adjacent water molecules. The results can provide a useful reference for the thermal aging test of low density polyethylene (LDPE).
【作者单位】： 中国南方电网超高压输电公司广州局;
【分类号】：TM21
本文编号：2306372
[Abstract]:In order to study the mean square shift of (Tg), polyethylene chain and the diffusion coefficient of water molecules in the system, the glass transition temperature of nano-silica doped low density polyethylene (LDPE) system was studied. The complex simulation model of amorphous region, nano-silica and moisture of low density polyethylene (LDPE) (LDPE) was constructed by molecular dynamics (MD) simulation method. The results show that the glass transition temperature of the composite system can be reduced by moisture. The addition of nano-silica enhances the thermal stability of the composite model, raises the glass transition temperature of the composite system, and weakens the chain movement of polyethylene molecules in the composite system. The diffusion coefficient of water molecules increases with the increase of temperature. The addition of nano-silica will reduce the diffusion coefficient of water molecules in the system to a certain extent. When the temperature is about 300K, the water molecules will reunite locally through the hydrogen bond interaction between the molecules, and the increase of temperature will break the hydrogen bond interaction between the adjacent water molecules. The results can provide a useful reference for the thermal aging test of low density polyethylene (LDPE).
【作者单位】： 中国南方电网超高压输电公司广州局;
【分类号】：TM21
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