Preparation of exfoliated clay/polymer nanocomposites via organosilane grafting and in situ ATRP of glycidyl methacrylate

Clay/polymer nanocomposites, of the type montmorillonite/polyglycidyl methacrylate) (MMT/PGMA), were synthesized via atom transfer radical polymerization (ATRP). MMT was amino-silanized and then reacted with 2-bromoisobutyryl bromide (BIB) to provide -NH-C(=O)-C(CH 3 ) 2 Br groups attached to the clay. The latter (MMT-SiBr) served as macroinitiator for the in situ ATRP of GMA. The resulting MMT/PGMA nanocomposites were found to be highly exfoliated, as judged by X-ray diffraction (XRD) measurements. Thermogravimetric analysis (TGA) and XPS analyses suggest that the nanocomposites have PGMA-rich bulk and surface. Indeed, the mass loading of PGMA reached 65 wt. % while XPS spectra, particularly the high-resolution C1 s region, resemble those of pure PGMA. These clay/PGMA nanocomposites are suitable as nanofillers for epoxy adhesives, since PGMA chains are both compatible with epoxy resins and reactive towards crosslinkers via the pendant glycidyl groups from PGMA grafts.