Micromechanical deformation processes in dependence on the phase morphology in various toughened and particle filled semicrystalline polymers have been investigated by several in situ electron microscopic techniques, inclluding transmission (TEM), scanning (SEM), and high voltage electron microscopy (HVEM). From the study of phase structure of modifier particles two morphological standard types are classified: the binary system (homogeneous modifier particles, dispersed in a homogeneous matrix), and the ternary system (heterogeneous modifier particles, dispersed in a homogeneous matrix). Taking into account these categories, and the phase adhesion between the modifer particles and the matrix, micromechanical deformation processes have been characterized. In all bllend systems studied, the enhancement in toughness and the major part of energy dissipation results from the shear yielding (flow processes) of matrix material triggered by microvid formation. According to where microvids appear, two different mechanisms are defined: (i) caviation in the stretched rubber shell or inside particles and (ii) debonding at the interface between particles and matrix. From these experimental results a three-stage-deformation mechanism is proposed.
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