Pressure reinforcement of particulate polymeric composites originated by adhesive debonding

Particulate elastomeric composites exhibit considerable reinforcement when they are extended under moderate superposed pressures. Numerous experiments have shown that this effect is provoked by pore formation and relevant matrix overstraining. The interfacial friction between the debonded matrix and filler has as well been shown to influence this phenomenon markedly. It seemed reasonable first to study separately elastic and frictional contributions to reinforcement. The paper examines the reinforcement effect caused by elastic pore suppression under superposed pressure without taking into account the frictional effect. The structural element has the form of a rubber neo-Hookean cylinder (matrix) with a rigid spherical inclusion (filler) at the center. Quantitative dependence of the reinforcement on the volume suppression, pressure, degree of extension, volume content of the inclusion and modulus of the matrix has been obtained in the framework of large deformation. The analysis of these data has shown that theoretical results were in good agreement with the available experimental evidence. Some peculiarities of the phenomenon have been established such as the weakening of the extent of reinforcement with the extension, higher reinforcement under negative pressures, two different geometrical modes of the vacuole compression depending on the extension and the range of matrix moduli where the reinforcement effect becomes negligible.