Synthesis and properties of poly(4-vinylpyridine)/montmorillonite nanocomposites

Abstract

4-Vinylpyridine monomer was mixed with organically modified montmorillonite (MMT) and polymerized in the presence of 2,2′-azoisobutyronitrile as radical initiator. Organophilic montmorillonite was obtained by using a block copolymer of poly(methyl methacrylate) and quaternized poly(4-vinylpyridine) (P4VP) in different compositions. X-ray diffraction (XRD) and thermogravimetric analysis confirmed that the block copolymer is inserted between MMT layers while the interlayer distance is expanded. The P4VP nanocomposites obtained from the block copolymer with the longer P4VP block exhibited no XRD peak, suggesting an exfoliated structure. These composites showed increased storage modulus and thermal stability at a very low loading of 1 - 2 wt.-%, compared to neat P4VP. Scanning electron microscopy and atomic force microscopy analyses were also conducted for selected nanocomposites.