Structural features of deformation of rubbery polymers

A direct microscopic procedure was used for studying the mechanism of deformation of rubbery polymers. To visualize structural rearrangements in the deformed polymer, it is sufficient to decorate its surface with a thin rigid coating prior to deformation. As a result of deformation and related changes in the surface area of the test polymer sample, the formed relief is changed in the coating and in the adjacent polymer layer. Direct microscopic examination and an analysis of the specific features of the induced microrelief allow one to gain important information concerning the mechanism of deformation of a polymer support. It is found that the deformation and shrinkage of a plasticized poly(vinyl chloride) (PVC) and a crosslinked isoprene rubber (SKI) are accompanied by appreciably different structural rearrangements. The tensile drawing and shrinkage of the plasticized poly(vinyl chloride) proceed along with the formation of morphologically similar structures in the surface polymer layer with the deposited metallic coating. In the case of SKI, one may observe a marked difference in patterns corresponding to direct (stretching) and reverse (shrinkage) deformation processes. It is assumed that this effect is related to the difference in the molecular mobility of crosslinked (SKI) and non-crosslinked (PVC) polymers.