Electron microprobe analysis as a novel technique to study the interface between thermoset and thermoplastic polymers

Bilayer films between thermoset epoxy and thermoplastic poly(vinylpyrrolido ne) (PVP) were prepared by casting a stoichiometric mixture of the uncured diglycidyl ether of bisphenol A epoxy (DGEBA) and 4,4'-diaminodiphenylsulfo ne (DDS) on a PVP film and then curing the system in a two-step process und er an inert gas atmosphere. The resultant interface was analyzed by electro n microprobe analysis (EMP). The EMP results demonstrated that the interfac e formation was predominantly controlled in the initial cure stage, and tha t the diffusion at the interface was suppressed significantly after the epo xy formed the network structure, New EMP techniques were developed to analy ze the polymer-polymer interface and to obtain not only the concentration p rofile but also the image of the interface. The limit of the resolution was 1.6 mu m under the experimental conditions employed in this study. (C) 199 9 Elsevier Science Ltd. All rights reserved.