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Organophilic montmorillonite (OMMT) was synthesized by cationic exchange reaction of Na+‐MMT and vinyl benzyl triethyl ammonium chloride (VBTAC) as a reactive organic modifier in an aqueous solution. A series of styrene (St)/acrylic acid (AA)/OMMT nanocomposite hydrogel containing different wt% of OMMT was synthesized through in situ polymerization using γ‐ray. The samples were characterized using Fourier transform infrared (FTIR), X‐ray powder diffraction (XRD), and transmission electron microscope (TEM), whereas thermal stability was examined by thermogravimetric analysis (TGA). The adsorption capacity and rate for both Acid Green B (anionic) and Maxilon C.I. Basic (cationic) dye including adsorption kinetics and isotherm were investigated at 30°C. TEM measurements showed spherical nanosized particles of average diameter 30–40 nm and XRD suggested the formation of exfoliated nanocomposite. TGA measurements showed that the addition of OMMT did not enhance the thermal stability where the onset temperature of the degradation for all samples was around 125°C. The effect of some important parameters on dye adsorption such as solution pH, initial dye concentration, and contact time was investigated. The equilibrium data obtained in batch experiments were correlated to Langmuir and Freundlich isotherm equations. Results showed that the adsorption of Acid Green B fitted well to the Langmuir model while the adsorption pattern of Maxilon C.I. Basic followed the Freundlich isotherm, which suggests heterogeneity of the adsorption sites on the nanocomposite. POLYM. COMPOS., 35:2353–2364, 2014. © 2014 Society of Plastics Engineers

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To overcome mass transfer limitations which are usually encountered on immobilizing active catalysts, cationic latex particles were used as support for the cobalt(I1) complex of disodium N,hP-bis(salicylidene)ethylenediamine-5,5'-disulfonate (1). The cationic latex 2 was prepared by emulsion copolymerization of chloromethylstyrene (m/p-isomer mixture 60/40) and divinylbenzene (m/p-isomer mixture) followed by treatment with trimethylamine. The latexbound catalyst from 1 and 2 was found to considerably increase the reaction rate of the autoxidation of 2,6-di-tert-butylphenol in water as compared with the conventional polymer-free system. Reaction products were identified as the oxidative coupling product 3,3',5,5'-tetratert-butyldiphenoquinone (3,3',5,5'-tetra-ter~-butyl-4,4'-dioxo-l,l'-bicyclohexa-2,5-dieny~idene) and 2,6-di-tert-butyl-1,4-benzoquinone. All reactions showed an induction period before the start of dioxygen consumption. The rate of autoxidation in the three-phase mixtures of water, latex particles, and phenol droplets was not affected significantly by the method of mixing. The reaction rate increased as the concentration of 1 increased. Increasing the partial pressure of dioxygen in the range between 0,25 and 1,0 atm (2,53 . lo4 -1,Ol . 10' Pa) gave a small increase in rate. The colloidal latex catalyst from 1 and 2 showed some loss of activity after successive runs. 0 1993, Huthig & Wepf Verlag, Basel CCC 0025-1 16X/93/$05.00