The effects of silica fillers on the gelation and vitrification of highly filled epoxy-amine thermosets

Highly filled thermosets are used in applications such as integrated circui t (IC) packaging. However, a detailed understanding of the effects of the f illers on the macroscopic cure properties is limited by the complex cure of such systems. This work systematically quantifies the effects of filler co ntent on the kinetics, gelation and vitrification of a model silica-filled epoxy/amine system in order to begin to understand the role of the filler i n IC packaging cure. At high cure temperatures (100 degreesC and above) the re appears to be no effect of fillers on cure kinetics and gelation and vit rification times. However, a decrease in the gelation and vitrification tim es and increase the reaction rate is seen with increasing filler content at low cure temperatures (60-90 degreesC). An explanation for these results i s given in terms of catalysation of the epoxy amine reaction by hydrogen do nor species present on the silica surface and interfacial effects.