Rheo‐optical FTIR spectroscopy of epoxy resins

Abstract This article presents the results of the first application of rheooptical Fourier transform infrared (FTIR) spectroscopy to monitor orientation phenomena in highly crosslinked epoxy/amine networks during the uniaxial deformation above their glass transition temperature. The resins were prepared from the diglycidyl ether of bisphenol‐A (DGEBA) and various polyether di‐and triamines in order to influence the structure of the network formed. The molecular orientation is discussea with respect to network density and structure. The orientation behavior is mainly determined by the flexibility of the polyether chain and the homogeneity of the network structure. Additionally, the epoxy resins were subjected to successive loading‐unloading cycles. The investigations show that the orientation of epoxy networks in their rubbery state is completely reversible, and that no significant fatigue due to gradual chain rupture occurs until sample failure. © 1995 John Wiley & Sons, Inc.