Heating of Polymer in Shear Bands

Abstract—During compression and tension of amorphous polymers, plastic flow is often localized in a system of shear bands. Shear stresses do the work which is transformed into heat, and the polymer is heated up. A set of intersecting shear band has been observed during rolling of amorphous poly(ethylene terephthalate). The band appearing later has remained straight, whereas this appearing earlier has become kink-shaped. The shear deformation in the band has been constant along the thickness, equal to 78 ± 14%, which corresponds to the kink angle 38 ± 5°. Analytical solution describing the temperature distribution over the shear band thickness has been obtained. The temperature has been maximal at its front. The calculations have led to the conclusion that the heating in shear bands is a phenomenon specific of polymers and can be neglected for in the case of metals. Upon the appearance, temperature in thin bands has been increased proportional to square root of the band thickness. As the thickness has increased, the maximal temperature in the band has approached the adiabatic limit, at which the heat losses can be neglected for.