WATER SORPTION AND TEMPERATURE EFFECTS ON THE DYNAMIC MECHANICAL-BEHAVIOR OF EPOXY-MATRIX PARTICULATES

The effect of water absorption on the dynamic mechanical properties of composite systems consisting of a cold-setting epoxy matrix filled with iron particles was investigated over a wide temperature range. Storage moduli and loss factors of these composites were determined and the effect of water-conditioning temperature was examined. To minimize the complication of higher-order particle-particle interaction, a low filler content was used. Results indicate a strong dependence of dynamic properties on the water-conditioning temperature. It was found that depending on the water-conditioning temperature the presence of water molecules may either enhance or reduce the dynamic properties of the composite. The observed behaviour was similar to the respective behaviour of the same materials when tested in flexure. This behaviour was explained in terms of the dual action of absorbed water as a plasticizer and a crazing agent which deteriorates in a different way the physical and mechanical integrity of the epoxy-matrix composite.