Abstract
Summary: A novel amine terminated elastomeric siloxane modifier (SA amine) for epoxy networks has been synthesized and characterized. The dual role of SA amine not only as a curing agent and but also as a toughener was studied. Curing studies of conventionally available epoxy resin, diglycidyl ether of bisphenol A (DGEBA) using SA amine along with diamino diphenyl sulfone (DDS) has been carried out. An interesting feature was the complete miscibility of the siloxane oligomer with DGEBA. In addition, the cured laminates were analyzed for thermal, mechanical, and surface morphology and also for their chemical resistance. The thermo mechanical properties were studied using dynamic mechanical analysis. The modified systems showed very high thermal stability. A single glass transition temperature was observed for the modified systems. The moisture resistance of the samples improved notably with the introduction of siloxane into the systems. The modified systems also improved the impact strength of the materials to a greater extent (35β50%) even though there was a small decrease in their tensile properties (12%). The system with maximum SA amine content showed the higher impact strength value and also a higher thermal stability without any phase separation in the morphology.
Representation of the crosslinking pattern of the resin systems.
magnified imageRepresentation of the crosslinking pattern of the resin systems.