| Abstract
| - Laponite clay was modified with combinations of organic ammonium surfactant and/or covalentlybound poly(methyl methacrylate) (PMMA). Two polymer attachment methods were explored, one throughreaction of a methacrylate compound with the clay's silanol group followed by in situ free-radicalpolymerization of methyl methacrylate (MMA), and the other through attachment of an ATRP initiatorfollowed by brush polymerization. The free-radical method yielded clays with ca. 75 wt % of polymerbound though multiple attachment sites to the clay, whereas the ATRP method yielded ca. 68 wt % ofbound polymer attached only at the chain end. The PMMA-modified clays were very dispersible inorganic solvents and were solvent-blended with commercial PMMA at 1, 3, 5, and 10 wt % concentrations.The resulting nanocomposites were optically transparent and homogeneous. TEM images showed mixedintercalated and exfoliated dispersions. DMA analysis showed an increase in room temperature modulusof 50% at 5 wt % concentration for the clay with no surfactant and PMMA free-radical attachment.
- Laponite clay was modified with combinations of organic ammonium surfactant and/or covalently bound PMMA. PMMA was attached to Laponite by reaction of the clay's silanol groups with a methacrylate compound followed by free-radical polymerization of MMA or by attachment of an ATRP initiator followed by MMA polymerization. The clays were then solvent-blended with commercial PMMA, and the nanocomposites were evaluated with DMA, DSC, and TEM.
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