Comparative Rheological and Fracture Properties of Epoxy Resins in the Glass Transition Region.

摘要

The rheological and fracture properties of technically and commercially important representatives of three classes of high polymers, elastomer (SBR), thermoplastics (PVC), and thermosetts (epoxy resins) are directly compared in terms of response 'master' functions in the region from glassy state through rubbery state. Application of the time temperature reduced variables treatment reduces the magnitudes of response to thermodynamically equivalent states at 296 K. The rheological time scale of response is reduced to equivalent states of molecular fractional free volume, from a further consideration of reduced variables, fixed by convention at T sub g + 50 K where T is the glass transition temperature of the particular polymer g. The dynamic properties, in terms of the storage modulus and loss tangent and tensile properties, in terms of a relaxation modulus, the true fracture stress and fracture strain are qualitatively compared and discussed from the standpoint of chemical composition and macromolecular architecture. The interrelations between microstrain dynamic properties and macrostrain tensile deformation and fracture properties are identified.