Pressure effects on the cure properties of an epoxy resin using different hardeners

摘要

Epoxies have a number of industrial applications, ranging from bond technology to structural composites. These compounds are frequently used in the aeronautic industry for the matrix of composite parts. In these applications, curing under pressure is usually needed. Although there are some works that study the cure under pressure by DSC, the study of its effect on the degree of cure was little investigated. Several works have studied the influences of pressure over the kinetic reaction of epoxy resins using pressure-volume-temperature analysis (PVT) and also, the pressure effect in the curing of polyester or polyurethane resins has been studied by PDSC. Moreover, other study use Temperature Modulated Pressure DSC (TMPDSC) to study the pressure effect on the curing reaction of an epoxy system and to evaluate the vitrification time by quasi-isothermal modulated experiments at different pressures. In this work the effect of the pressure on the process of curing of Diglycidyl Ether Bisphenol A (DGEBA) using different curing agents is studied by PDSC. Curing experiments at several pressure levels were conducted in a pressure DSC-cell mounted on a TA Instruments MDSC Q2000. The glass transition temperature of the samples cured at different pressures was evaluated at atmospheric pressure. The interaction of the hardener molecular structure with the pressure effect was investigated.