聚丙烯腈溶液凝固体系中组分间相互作用及其演变

Evolution of the interactions between components during the coagulation of polyacrylonitrile solution

采用衰减全反射傅里叶变换红外(ATR FT-IR)研究了聚丙烯腈(PAN)/二甲基亚砜(DMSO)溶液在乙二醇作用下的凝固过程,利用二维相关分析方法对得到的红外谱图进行再处理,解析出相关峰之间的相互关系;进而从分子尺度上通过对特定基团的分析,研究了组分间相互作用及其演变规律,揭示了PAN溶液的凝固过程。结果表明,溶剂DMSO在PAN溶液中以单分子和聚集体的形式共存,对—CN形成一定的束缚隔离作用;随着凝固剂乙二醇分子的进入,由于DMSO和乙二醇之间较强的相互作用导致其逐渐从聚合物分子链间排出,DMSO分子团对—CN的束缚隔离作用被减弱;同时,PAN分子链间距缩小,当某一区域的DMSO减少到一定程度,PAN分子链由于—CN之间偶合交联作用相互靠近排列而发生宏观上的凝固现象。

The coagulation of polyacrylonitrile( PAN) solution in dimethyl sulfoxide( DMSO) by ethylene glycol( EG) has been studied by attenuated total reflection Fourier transform infrared( ATR FT-IR) spectroscopy. The spectra were treated by a two-dimensional correlation analysis method to resolve the overlapping bands and determine the relationships between specific bands. The evolution of intramolecular interactions and interactions in the PAN-DMSO-EG mixture can explain the mechanism of coagulation in molecular terms. The results showed that DMSO aggregates which exist in the PAN solution and interact with —CN moieties,became more weakly bound after addition of EG and diffusion began. DMSO was gradually expelled from the inner polymer chains as the process proceeded. Solidification eventually took place when PAN chains began to aggregate together via the interaction between —CN groups.