Effect of cross‐linking on hydrostatic creep of epoxy

Abstract

Abstract Samples of epoxy having three different degrees of crosslinking were subjected to several constant values of hydrostatic pressure ranging from 1000 psi to 80 ksi. Each period of constant pressure was followed by a period at atmospheric pressure. A continuing decrease in volume (creep), as measured by axial strain at constant pressure, was observed for pressures of 10 ksi and greater. The creep strain was recovered immediately upon pressure removal. Reapplication of pressure after a short period at atmospheric pressure resulted in the same creep behavior as that resulting from the first pressure. The least cross‐linked epoxy had the smallest creep rate and the smallest compressibility. These observations are consistent with the view that the leapt cross‐linked epoxy would be the most compact and have the least voids at points of cross‐linking.