TRANSFORMATION OF ADHESIVE CRACKS INTO CO HESIVE ONES IN PARTICULATED-FILLED POLYMERS

Theoretical consideration of the phenomenon of the tum of the interfac ial cracks into matrix, observed for some particulated-filled polymers , and estimation of the angle, at which the tum occurs, was given. The tum angles were determined from the equality of the increments of fre e energies, corresponding to further propagation of detachments, with a given angle, along interfacial surface, and to propagation of cracks in perpendicular direction. According to the estimation, the largest gain in the energy is achieved at angle ca. 40-degrees, in agreement w ith results of microscopic experiments.