Real-time dielectric studies of polymerizing systems

Abstract

The use of real-time dielectric relaxation spectroscopy (DRS) for monitoring changes in molecular mobility during reaction for thermosetting systems is described together with phenomenological and molecular theories of the time-dependent relaxation functions that are involved.Reduced molecular mobility normally leads to the diffusion control of a reaction and ultimately to glass formation at the polymerization temperature T p .We present new DRS results for a boroxine/epoxide system that show glass formation below a 'floor temperature' T F and very different behaviour above T F , when the dielectric properties become independent of time and an elastomer is formed.