Interfacial Effects on the Reinforcement Properties of Polymer-Organoclay Nanocomposites

摘要

The results of this work suggest that exfoliated forms of smectite clays would be good reinforcement agents for epoxy matrixes even in the absence of onium-exchange cations on the gallery surfaces. However, inorganic exchange forms of smectite clays are not able to form epoxide nanocomposites for both thermodynamic and kinetic reasons. Onium ions are needed to modify the surface polarity, thereby allowing thermodynamically favorable preloading of the galleries with polymer precursors. Also, as demonstrated in our earlier work, the acidity of the onium ions is needed in order to catalyzing the intragallery polymerization. Comparable intra- and extragallery polymerization rates are essential for achieving uniform clay nanolayer exfoliation in a monolithic polymer matrix. If the intragallery polymerization is too slow, only intercalated nanocomposites will be formed with tensile properties that are inferior to exfoliated nanocomposites.