聚丙烯腈热裂解产物的ESR和固体￣（13）CNMR研究

ESR AND SOLID STATE ^(13)C NMR STUDIES OF THE PYROLYTIC PRODUCTS OF POLYACRYLONITRILE

用电子自旋共振（ＥＳＲ）和固体￣（１３）ＣＮＭＲ研究了聚丙烯腈（ＰＡＮ）在不同裂解温度（Ｔ＿Ｐ）下的结构变化，当Ｔ＿Ｐ从２５０℃增加到６００℃，ＥＳＲ信号线形没有变化，ｇ值与Ｔ＿Ｐ无关，ΔＨ＿（ＰＰ）减小，自旋浓度（Ｎ＿Ｓ）开始增加，Ｔ＿Ｐ进一步升高，Ｎ＿Ｓ又减少．￣（１３）ＣＮＭＲ谱指出在不同Ｔ＿Ｐ下谱峰发生很大变化，与另文报道的红外及Ｘ－射经衍射结果一致，随Ｔ＿Ｐ升高，ＰＡＮ逐渐脱去小分子形成具有环化共轭结构的产物．

structural changes of polyacrylonitrile（PAN）in pyrolysis have been studied byusing ESR and solid state ^(13)C NMR．The line shape and g－factor remained constantover thc whole temperature range（250－600℃）．The ESR line widths，ΔH_(PP) decreasewith temperature．The spin concentration increased with the increase of temperature inthe fiist stage and then decreased with further increase of temperature．Great changeof ^(13)C NMR spectra had been found in the process．All the results show that compli-cated fused conjugated ring systems are formed in the pyrolysis．