Two Cases of Mapped Epoxy Interphases

Two examples of the characterization of IP stiffness profiles using FMM are given in Fig. 8.6. In both cases mixtures of epoxy resin with aliphatic/cycloaliphatic amines were cured in the presence of a Cu component. The investigated surface was prepared either by a replica technique similar to that described in Fig. 8.4, or by sectioning of a bulk sample (see Fig. 8.6a, b and Fig. 8.6c,d, respectively). 

The ROAs are marked with (a) black and (c) white borderlines, respectively. N denotes the direction perpendicular to the mean local tangent [T) of the interfacial border. Adapted from Ref [18]. 

Although these two IPs possess different widths, in both cases the epoxy stiffness was found to be reduced in the vicinity of the interfacial border between Cu(oxide) and epoxy. In the second case, the existence of a much wider IP can 

Another class of adherends is that of thermoplastic polymers. In contrast to metal adherends, thermoplastics are not impenetrable and thus absorption effects can be expected in addition to adsorption phenomena. Hence, given sufficient conditions for preferential absorption, a considerable mass uptake by the thermoplastic can occur, potentially resulting in significant stoichiometric imbalances on the epoxy side. Apart from the driving force for absorption of molecules from the liquid epoxy formulation, it is the diffusivity of these molecules within the thermoplastic which plays a major role in the interdiffusion process. In particular, the diffusivity is affected by the mobility of the host molecules. Thus enhancement of diffusivity occurs in the glass transition region and at higher temperatures when intermolecular cooperative motion is activated. 

An SEM micrograph and corresponding concentration maps resulting from EDX are given in Fig. 8.7. 

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