DYNAMICAL MECHANICAL ANALYSIS OF GLASS-TRANSITION PEAKS IN POLYMERS AND COMPOSITES

In an earlier paper, the mechanical loss peaks of an epoxy thermoset r esin were shown to be fitted by a non-Arrhenius power-law expression f or the temperature dependence of the relaxation time with allowance fo r nonexponential relaxation behaviour. We have now extended this type of analysis to characterize the loss peaks in two non-crystalline ther moplastic polymers, poly(methyl methacrylate) and polycarbonate, and w e provide an example of how the analysis may be used to demonstrate su btle differences in the behaviour of composite systems, in particular, the way in which interphase coatings on carbon fibres may affect the loss behaviour.