Use of clay-anchored reactive modifier for the synthesis of poly (styrene-co-butyl acrylate)/clay nanocomposite via in situ AGET ATRP

Atom transfer radical polymerization using activators generated by electron transfer (AGET ATRP) was employed to synthesize well-defined poly (styrene-co-butyl acrylate)/clay nanocomposites. Dodecyltrimethylammonium bromide (DDTMAB) and Vinylbenzyltrimethylammonium chloride (VBTMAC) surfactants were used as clay modifier. The classical surfactant is used to expand the interlayer gallery of montmorillonite; however, double bond of reactive modifier participates in chain propagation process and forms clay-attached polymer chains. Subsequently synthesis of attached and free poly (styrene-co-butyl acrylate) chains and their composition was confirmed by Fourier-transform infrared spectroscopy (FTIR) and proton nuclear magnetic resonance spectroscopy (H-1 NMR). Narrow distribution of nanocomposites molecular weight was confirmed by gel permeation chromatography (GPC). Partially exfoliated clay layers in the copolymer matrix were revealed by X-ray diffraction (XRD) and transmission electron microscopy (TEM). Thermal properties of the nanocomposites were evaluated by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). Thermal decomposition of the nanocomposites was hindered in the presence of nanoclay. Dynamic mechanical thermal analysis (DMTA) results show that addition of nanoclay was also resulted in enhanced storage modulus (E') in comparison with the neat copolymer. Lower glass transition temperature of nanocomposites was displayed by DSC.