Intra‐ and extra‐gallery reactions in tri‐functional epoxy polymer layered silicate nanocomposites

Abstract

Abstract Achieving a high degree of exfoliation in epoxy‐based polymer layered silicate (PLS) nanocomposites is crucial to their successful industrial application, but has hitherto proved elusive. In this work, a system is presented which shows significant promise in this respect. The isothermal cure of PLS nanocomposites based upon a tri‐functional epoxy resin (TGAP) has been studied by DSC, and displays two exothermic peaks. The first peak, very rapid, relates to a homopolymerization reaction within the intra‐gallery regions, while the second peak reflects the bulk crosslinking reaction. The occurrence of the intra‐gallery reaction before the bulk reaction enhances the degree of exfoliation in the cured nanocomposite. Furthermore, pre‐conditioning the resin/clay mixture before adding the curing agent and effecting the isothermal cure also allows a greater extent of intra‐gallery reaction to occur before the extra‐gallery epoxy‐amine reaction. Consequently, this system results in a high degree of exfoliation, as revealed by transmission electron microscopy. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013