Iodine-doped (I-doped) mesoporous titania with a bicrystalline (anatase and rutile) framework was synthesized by a two-step template hydrothermal synthesis route. I-doped titania with anatase structure was also synthesized without the use of a block copolymer as a template. The resultant titania samples were characterized by X-ray diffraction, Raman spectroscopy, Fourier transform infrared, nitrogen adsorption, transmission electron microscopy, X-ray photoelectron spectroscopy, and UV-visible absorption spectroscopy. Both I-doped titania samples, with and without template, show much better photocatalytic activity than commercial P25 titania in the photodegradation of methylene blue under the irradiation of visible light (>420 nm) and UV-visible light. Furthermore, I-doped mesoporous titania with a bicrystalline framework exhibits better activity than I-doped titania with anatase structure. The effect of rutile phase in titania on the adsorptive capacity of water and surface hydroxyl, and photocatalytic activity was investigated in detail. The excellent performance of I-doped mesoporous titania under both visible light and UV-visible light can be attributed to the combined effects of bicrystalline framework, high crystallinity, large surface area, mesoporous structure, and high visible light absorption induced by I-doping.

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5,10-Dihydro-phenophosphazine-10-oxide(DPPA) served as a co-curing agent of 4, 4'-diaminodiphenylmethane for the curing reaction of bisphenol A diglycidyl ether (DGEBA) epoxy resin (EP). 1 H NHR spectrum tracking the reaction process of DPPA with DGEBA revealed that P-H bond of DPPA had the higher reactivity than its N-H bond for reacting with epoxy group. DPPA could promote the curing reaction of DDM with DGEBA. DPPA endowed epoxy resin with high flameretardant efficiency due to the unique combination of phosphorus and nitrogen in the phenophosphazine ring. The cured epoxy resin could pass V-0 rating of UL-94 test with limiting oxgen index (LOI) of 33.6% at only 2.5 wt% DPPA. The reduced peak heat release rate and total heat release, and increased char yield further verified the excellent flame retardancy for EP. Flame-retardant mechanism of the epoxy resin was investigated by thermogravimetry-fourier transform infrared spectrometry (TG-FTIR), scanning electron microscopy, element analysis and FTIR spectrometry. The results indicated that DPPA catalyzed epoxy resin matrix to form the rigid intumescent char and to generate the blowing-out effect.