聚卤乙烯单体性质及构型对链柔性和极性的影响

EFFECT OF MONOMER PROPERTY AND CONFIGURATION ON FLEXIBILITY AND DIPOLE OF POLY(VINYL HALIDES) CHAINS

基于旋转异构态模型和生成矩阵统计方法,推导了极性取代基高分子链均方回转半径和均方偶极矩改进的计算公式,应用于研究聚卤乙烯链构象和构型依赖的性质,包括均方回转半径和偶极矩特征比与构象能、链规整程度和温度的关系.发现构型规整的聚卤乙烯链特征比、温度系数和构象能依赖性质均呈现较大的差异,尤其是间同和全同构型链.如聚卤乙烯间同链偶极矩特征比随主要相互作用Eη变化比例在-0.62～0.05(J/mol)-1之间.相反,构型不规整的聚卤乙烯链的无扰尺寸则比较接近.聚氟乙烯、聚氯乙烯和聚溴乙烯无规链均方偶极矩特征比分别为0.80、0.69和0.59,均方偶极矩温度系数为-0.07×10-3～-0.53×10-3 K-1,与实验结果符合.研究结果表明聚卤乙烯单体性质和构型对其链柔性和链极性的影响是显著的.

The improved mean-square radius of gyration and dipole moment of polymers with dipole substitutes are deduced by the rotational-isomeric-state model and the generator matrix method,and used to investigate the configuration-conformation dependent property of poly（vinyl halides）,including the relation of them with the conformational energy,the chain tacticity and temperature.It is found that the differences of characteristic ratios,the temperature coefficients and conformational energy dependent property for stereo-regular poly（vinyl halides） polymers are obvious,especially for the isotactic and syndiotactic chains.The differentiates of the dipole ratios with respect to the first conformational energy Eηof the syndiotactic poly（vinyl halides） are in-0.62~0.05（J/mol）-1 for instance.However,the unperturbed dimensions of stereo-irregular poly（vinyl halides） chains are rather close to each other.The dipole characteristic ratios of atactic poly（vinyl fluoride）,poly（vinyl chloride） and poly（vinyl bromide） are obtained to be 0.80,0.69 and 0.59,respectively,and their temperature coefficients are-0.07×10-3^-0.53×10-3K-1,which are in agreement with the experiment dada.The results show that the effect of monomer property and configuration on the flexibility and dipole properties of poly（vinyl halides） is remarkable.