原位FTIR光谱法研究联萘基环氧树脂体系的固化反应

用原位FTIR光谱方法分析了联萘基环氧单体DGEBN与胺类和酚类固化剂的固化反应.固化体系中,在环氧与固化剂混合之后和反应之前就存在特殊的分子间作用力(包括氢键作用),这可能是由环氧-固化剂产生的环状中间体络合物使环氧基的伸缩振动频率产生红移所致.随着固化反应的进行,环氧基的振动吸收峰分裂成二重峰,分裂转变时间所对应的转化度接近理论凝胶点.4种固化剂与DGEBN进行固化反应表现出不同的反应活性.用FTIR和DSC两种方法分别得到的转化度随时间的变化关系具有可比性.

In Situ FTIR Spectroscopic Investigation on the Curing Reaction of Binaphthyl Epoxy Systems

An investigation on the curing reactions of 2,2'-diglycidyl-1,1'-binaphthyl(DGEBN) systems containing amino and phenolic hardeners was carried out by in situ Fourier transform infrared(FTIR) spectroscopy.The shifts in frequency of epoxy stretching vibration to lower values in the uncured systems suggest the existences of specific intermolecular interactions,including hydrogen bonding by solvent-mixing the cure formulations.The hydrogen-bonded intermediate complexes consisting of epoxy and the reactive groups of hardeners were thought to include cyclic structures.As the reactions progressed,a new peak emerged between 914-916 cm-1,which is associated with "free" epoxy groups.This emergence is related to the theoretical gel point.The four hardeners showed different reactivities towards DGEBN.The kinetic analysis derived from FTIR data was in good agreement with the result obtained by DSC method.