RELATIONSHIP BETWEEN INTERFACIAL PHENOMENA AND VISCOELASTIC BEHAVIOR OF LAMINATED MATERIALS

A literature review shows that the main arguments used to describe vis coelastic behavior of polymer composites are the existence of an inter phase and/or physico-chemical matrix-reinforcement interactions. The p urpose of this investigation was to study the influence of both of the se parameters on the viscoelastic behavior of a sandwich structure. Us ing a theoretical approach of the mechanical coupling between phases i n laminate composites, the interphase influence is shown to be negligi ble. In order to understand the influence of an interphase on viscoela stic features of laminates, some metal/polymer/metal laminates were pr ocessed under various conditions to obtain different degrees of metal/ polymer adhesion. Dynamic mechanical spectroscopy tests reveal that bo th the amplitude of the main loss factor peak and the low temperature apparent modulus increase with the adhesion. Finite elements calculati ons show that discontinuities of displacements at the metal/polymer in terface explain the loss peak changes. The continuity of displacements is ensured only from a threshold value of the peel energy.