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旋转异构态模型的三重态理论认为,高聚物链上每个键的旋转角可取三种分列的值,分别对应于旋转态。它们是:反式(t),左旁式(g~+)和右旁式(g~-)。线型高聚物的构象态用组成链的一系列键的旋转态来表示。例如:tg~+g~+ttg~-t…… 一条由n个键组成的线型链,由于每个键有三种旋转角,故它可以有3~(n-2)个不同的构象(两个端键的旋转不影响构象态)。本文旨在研究这样一个系综里平衡态下Polyoxymethylene(POM)的热力学性质。 POM链结构显示在图1.它的主链上是CH_2和O的交替有序排列。C—O键长是1.43A,C—O—C和O—C—O角近似为四面体(110±2°)角。旋转角φ_i=0°,φ_g~±=±120°。
The triplet theory of the model of the rotational isomerism states that the rotation angle of each bond on the polymer chain can take three separate values corresponding to the rotational states, respectively. They are: trans (t), left side (g ~ +) and right side (g ~ -). The conformational state of a linear polymer is represented by the rotational states of a series of bonds that make up the chain. For example: tg ~ + g ~ + ttg ~ -t ...... A linear chain composed of n keys, which can have 3 ~ (n-2) different conformations because each key has three rotation angles The rotation of the two end bonds does not affect the conformational state). The purpose of this paper is to study the thermodynamic properties of Polyoxymethylene (POM) in such a system at equilibrium. The POM chain structure is shown in Figure 1. Its main chain is the alternating order of CH2 and O. The C-O bond length is 1.43 A and the C-O-C and O-C-O angles are approximately tetrahedral (110 ± 2 °). Rotation angle φ_i = 0 °, φ_g ~ ± = ± 120 °.