| abstract |
A thermoplastic vulcanizate (TPV) is produced by melt blending until the volume fraction of dispersed rubber particles is greater than 0.5, preferably from 0.55 to 0.95, the remaining being the dispersed continuous plastic phase in a manner so as to develop a morphology which generates optimum elastic recovery. The majority (by volume) of large rubber particles are adjacent a small particle which is separated from one or more large particles by a critically thin, less than 0.1 $G(m)m thick, ligament of deformable plastic. When the majority of large particles evidence this morphology, as seen in a transmission electron microscope (TEM) photomicrograph, the TPV exhibits unexpectedly higher elastic recovery than if the ligaments were thicker. The foregoing is simulated in a micromechanical model which confirms, and in retrospect, predicts the observed actual elastic recovery of the TPV. |