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为了改进无机高分子链偶极矩的计算,在旋转异构态模型和生成矩阵统计方法基础上,导出了可以同时考虑骨架键和侧基极性的均方偶极矩公式,应用于对称和不对称聚硅氧烷高分子链的偶极矩构象构型统计性质的分析,及聚二甲基硅氧烷(PDMS)链、聚甲基苯基硅氧烷(PMPS)链是否考虑侧基极性的偶极矩比较。计算结果表明,PDMS的偶极矩特征比值0.36与实验结果一致,它大于忽略侧基极矩的特征比值约46%,均方偶极矩温度系数为1.29×10-3K-1,无规聚甲基苯基硅氧烷链(50%i-PMPS)的均方偶极矩特征比和温度系数分别为0.61和1.73×10-3K-1.不考虑侧基极性的均方偶极矩特征比与PDMS不考虑侧基时趋于同样的值0.20.对PMPS偶极矩与链规整性关系研究发现,PMPS间同链的均方偶极矩要大于全同和无规链,而全同链温度系数最大.均方偶极矩对一级相互作用能的依赖程度依次按间同链、无规和全同链顺序增加,而间同和全同链均方偶极矩受二级相互作用能的影响要大于无规链.
In order to improve the calculation of the dipole moment of inorganic polymer chains, a mean square dipole moment formula that can simultaneously consider the skeletal bonds and pendant polarities is derived based on the statistics of the rotational isomerism and the generation matrix. The statistical properties of the conformational structure of the asymmetric polysiloxane chains and the PDMS chains and the side chain of polymethylphenylsiloxane (PMPS) Polarity of the dipole moment comparison. The calculated results show that the PDMS dipole moment ratio 0.36 is consistent with the experimental result, which is larger than 46% of the ignoring side base moment and the temperature coefficient of mean square dipole moment is 1.29 × 10-3K-1. The mean square dipole moment and temperature coefficients of the methylphenylsiloxane chain (50% i-PMPS) were 0.61 and 1.73 × 10-3K-1, respectively. The mean square dipole moment The characteristic ratio tends to be the same as that of PDMS when the side groups are not considered. (2) The relationship between PMPS dipole moment and chain regularity shows that the mean square dipole moment of homophase chain in PMPS is greater than the same and random chain, The temperature coefficient of the chain is the largest.The mean dependence of the mean square dipole moment on the first order interaction energy is in the order of interchain, random and isostere chain, while the mean square dipole moment of interchain and isosceles chain is affected by the second order interaction The impact can be greater than the random chain.