MEASUREMENT OF THE EXTENT OF REACTION OF AN EPOXY-CYCLOALIPHATIC AMINE SYSTEM AND INFLUENCE OF THE EXTENT OF REACTION ON ITS DYNAMIC AND STATIC MECHANICAL-PROPERTIES

An investigation was carried out into the effect of the extent of reaction on the mechanical properties, in a mixture of an epoxy prepolymer and a cycloaliphatic diamine, above the gel point. First, the most adequate technique to approach the extent of reaction was chosen between differential scanning calorimetry, Fourier transformation infrared, and size exclusion chromatography. It was found that the differential scanning calorimetry gave a good estimate of the extent of reaction, measuring the glass transition temperature and using a modified DiBenedetto equation. Dynamic mechanical properties and static mechanical properties are shown to be highly dependent upon the extent of reaction. The beta relaxation was found to be responsible for the fracture properties at room temperature through the changes in extent of reaction.