Toughening Rigid Epoxy Using Novel Potassium Silanolate Ionic Interactions

A rigid and densely cross-linked epoxy resin is successfully toughened by introducing novel potassium silanolate ionic interactions, exhibiting simultaneous improvement in toughness, strength, modulus, and glass transition temperature. The ionic interactions are incorporated through a simple way into epoxy cured with a novel potassium silanolate ionic groups-containing amine curing agent. Small angle X-ray scattering/wide angle X-ray scattering and dynamic thermomechanical analysis results show that the ionic groups aggregated into multiplets and clusters in the prepared epoxy ionomers. The temporary physical cross-link effect of ionic aggregates and the consequently formed chain-restricting ionomeric nanodomains account for the stiffening and toughening performance. Furthermore, the densely cross-linked epoxy ionomers possess high stretchability at elevated temperature (about 800% at 200 degrees C) due to the dynamic ion-hopping effect.