High-Interlayer-Spacing Modification of Layered Clays and their Amphiphilic Self-assembling Properties

摘要

The naturally occurring layered silicates are conventionally applied in versatile areas. In recent years, silicate clays have found important uses in polymer/layered silicate (PLS) nanocomposites with significantly improved thermal and mechanical properties. The high aspect ratio and large surface area of the layered structure promote strong interactions with organic polymers on the molecular level. Utilization of these hydrophilic silicates requires an organic modification using low molecular weight ionic exchange agents such as alkylammonium derivatives or phosphonium salts. For example, the common montmorillonite clay is generally intercalated with C12-18 alkyl quaternary ammonium salts to become an organoclay with a 28 A basal spacing. The organic incorporation renders the clay compatible with polymer matrix.