具有极性大侧基乙烯基聚合物的分子尺寸和均方二极矩

Abstract

The formulas of basic quantities, mean-square radius of gyration and mean-square dipole moment, are re-deduced by the rotational-isomeric-state model and the generator matrix method with considering large side groups of polymers. From investigation for the configuration-conformation dependent properties of poly( N -vinylcarbazole) (PVK), poly( p -chlorostryere) (PPCS), poly(2-vinyl pyridine) (P2VP) and poly(vinyl pyrrolidone) (PVP), the characteristic ratios of mean-square dipole moment are obtained 0.55, 0.57, 0.48 and 0.37, respectively, and the ratios of mean-square radius of gyration are 2.07, 1.74, 1.11 and 1.52, respectively. The temperature coefficients of the isotactic chains, in range of -6.1×10 -3 ~ 2.1×10 -3 K -1 , are more than that of the syndiotactic chains and atactic chains. From comparing the constrained relation of the ratios, it is found that effect of polymerization degree of chains, the chain tacticity and conformational energies on the basic quantities of PPCS, PVP and P2VP are obvious relatively. Moreover, the larger side groups of PVK chain result in the greater characteristic differences between the mean-square dipole moment and mean-square radius of gyration. From contrasting the results of improved calculation, it is concluded that the consideration of orientation and dimension of dipolar side groups in calculation of mean-square dipole moment and radius of gyration are very significant. Therefore, it suggests that the effect of large dipolar side groups on the polarity and flexibility of polymers cannot be neglected.