Preparation of poly(methyl methacrylate)-grafted attapulgite by surface-Initiated radical polymerization

Poly(methyl methacrylate) (PMMA) was bonded on the surface of attapulgite (ATP) by using an ammonium persulfate amine redox initiation system via grafting from approach. ATP was modified with (3-aminopropyl)triethoxysilane to anchor amine groups on the surface, and then the amine-functionalized ATP was further treated with methacryloyl chloride and 4,4′-azobis(4-cyanovaleric acid) to give methacryl- and azo-functionalized ATP, respectively. Subsequently, surface-initiated graft polymerization of MMA in a soap-free emulsion was performed to afford ATP/PMMA hybrids. Meanwhile, graft polymerizations on the surface of methacryl- and azo-functionalized ATP were carried out for comparison. The grafting of PMMA on the surface of ATP was characterized by Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and thermogravimetric analysis (TGA). The crystal structure of hybrids was characterized by X-ray diffraction analysis. The morphology of hybrids was observed by scanning electron microscopy and transmission electron microscopy. The degree of grafting obtained from surface-initiated graft polymerization in a soap-free emulsion was found to be the greatest (29.4%) estimated from TGA. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131 , 41062.