Preparation of thermosensitive and visible-light responsible composites based on hydrogels of N-isopropylacrylamide/maleic anhydride-modified β-cyclodextrin copolymer and TiO2/multiwalled carbon nanotubes particles for degradation of methyl orange

The novel thermosensitive and visible-light responsible composites composed of poly(N-isopropylacrylamide-co-maleic anhydride modified -cyclodextrin) hydrogels (poly(NIPAM-co-MAH--CD)) and TiO2 doped with multiwalled carbon nanotubes (TiO2-MWCNTs) were prepared by an aqueous solution polymerization method with N,N-methylenebisacrylamide as crosslinker, potassium persulfate as initiator, NIPAM and MAH--CD as monomers, and TiO2-MWCNTs as functional filler. The structure and properties of the as-prepared thermosensitive composites were characterized with FTIR, XRD, XPS, TEM, BET, and UV-vis diffuse reflectance spectroscopy. The thermoresponsive property of the composites prepared under various synthesis conditions was investigated using equilibrium swelling ratio measurements at temperatures ranging from 20 to 45 degrees C. The swelling mechanism and kinetics of the composites were determined by analyzing the rate of swelling. The photocatalytic behavior of the thermosensitive composites was evaluated from the extent of removal of methyl orange (MO) from solutions under solar light irradiation. It was found that the thermosensitive composites have better removal efficiency of MO than pure TiO2. The thermosensitive composites exhibited easy separation and less deactivation after several runs. The advantages of the thermosensitive composites revealed its great practical potential in wastewater treatment. POLYM. COMPOS., 2013. (c) 2013 Society of Plastics Engineers