聚甲醛链构象熵的研究  

A Study on the Conformational Entropy of Polyoxymethylene Chains

作　　者：陈英才[1] 宋栩冰[2] 罗孟波[3] 许健民[3] 

机构地区：[1]台州师范专科学校物理系,浙江临海317000 [2]浙江大学化学系,浙江杭州310028 [3]浙江大学物理系,浙江杭州310028

出　　处：《科技通报》1999年第6期439-444,共6页Bulletin of Science and Technology

摘　　要：把聚甲醛（ＰＯＭ）链的主链分成Ａ、Ｂ两类，Ａ类以碳原子作为起始原子，Ｂ类以氧原子作为起始原子⒚用完全计算法计算了考虑排斥体积的Ａ、Ｂ两类聚甲醛链的构象熵ＳＡ 和ＳＢ⒚链长为奇数时，ＳＡ＝ ＳＢ；链长为偶数时，ＳＡ＞ ＳＢ，两者之间的差别很小，而且随链长的增长而减小⒚因此，对于ＰＯＭ 长链，可以不考虑Ａ、Ｂ之间的差别，认为ＳＡ＝ ＳＢ⒚结果表明，聚甲醛链的构象熵跟链长成正比，随温度的升高而增大。The polyoxymethylene (POM) chains are divided into two types, the originate atom of POM skeleton chain in type A is carbon while in type B is oxygen. The conformational entropies S A and S B of these two types of POM chains, with excluded volume, are calculated with exact enumeration method. For odd chain length, S A= S B; but for even chain length, S A> S B. The difference between S A and S B is very small and decreases with the increase of chain length. Therefore, for long POM chains, the difference can be omitted and taken S A= S B. Results show that the conformational entropy of POM chains is in proportional to chain length and increases with temperature. The conformation entropy tends to be zero when the temperature is about 25K, showing that the second order temperature of POM is about 25K.

关 键 词：聚甲醛链 构象熵 完全计算 混乱度 链长 

分 类 号：O632.17[理学—高分子化学] O631.1[理学—化学]