Stress—strain behavior of rubber‐reinforced glassy polymers

The main objective of this work has been to develop some rational hypothesis for the toughness of rubber‐modified glassy polymers as defined by the energy to rupture in a tensile measurement. It is shown that the rigid phase yields and that the toughness is a result of the large energy absorption involved in the cold drawing of the matrix. The rubber phase acts principally to induce a yielding in the matrix. A triaxial stress field in the environment of the dispersed particles results in local increases in free volume which aid in the initiation of cold drawing and provides the rubber with sufficient breaking stress to prevent premature crack propagation.