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A water-based fire resistive nano-coating was prepared via adding CaAlCO 3 -layered double hydroxides (CaAlCO 3 -LDHs) as an inorganic filler to intumescent fire retardant coating. The influence of CaAlCO 3 -LDHs on the coatings properties was investigated by thermogravimetry (TG), differential thermal analysis (DTA), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), cone calorimeter (CONE) and fire performance test. The results showed that CaAlCO 3 -LDHs could improve the quality of the residual char layer, increase the degree of the cross-linking and the carbon accumulation, and enhance the oxidation resistance of the char layer. The addition of 5 mass% CaAlCO 3 -LDHs to the coating could reduce the fire hazards of the coating itself, lower the rate of flame propagation and thermal degradation, and improve the char structure and fire resistance of the coating, which was attributed to the synergistic effect of CaAlCO 3 -LDHs and the intumescent fire retardant (APP/PER/MEL). [ABSTRACT FROM AUTHOR]

• Addition of MgAlCO 3 -LDHs and CaAlCO 3 -LDHs improved thermal insulation of IFR coating. • Metal ions from LDHs were chelated with carbon materials to form 3D reticular char. • LDHs can delay oxidation and improve degradation performance of char layers. MgAlCO 3 -layered double hydroxides (LDHs) and CaAlCO 3 -LDHs were respectively added as a synergistic agent to intumescent fire retardant (IFR) coatings. The 2.4 wt% of MgAlCO 3 -LDHs and the 6.7 wt% of CaAlCO 3 -LDHs were found to possess the best thermal insulation according to the fire performance tests. Further characterization by a cone calorimeter shows that the MgAlCO 3 -LDHs are superior to decreasing the specific extinction area of IFR coating, and the CaAlCO 3 -LDHs are advantageous in some other properties such as heat release rate, effective heat combustion and total heat release. Moreover, the X-ray diffraction (XRD) results infer that the flame retardant of char layer is primarily dependent on the amorphous structure formed after exposure to fire, the X-ray photoelectron spectroscopy (XPS) measurements of O 1s , C 1s , P 2p and N 1s reveal that the LDHs fillers suppress the oxidation of the IFR coating, and the Fourier transform infrared spectroscopy (FTIR) tests demonstrate that the LDHs protect the bridge frame structures. It is concluded that the LDHs can prevent the degradation and improve the thermal insulation of IFR coatings. [ABSTRACT FROM AUTHOR]

Abstract: A novel biosensor is developed based on immobilization of proteins on nanoflake-like SnS2 modified glass carbon electrode (GCE). With glucose oxidase (GOD) as a model, direct electrochemistry of the GOD/nanoflake-like SnS2 is studied. The prepared SnS2 has large surface area and can offer favorable microenvironment for facilitating the electron transfer between protein and electrode surface. The properties of GOD/SnS2 are characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), UV–vis spectroscopy, Fourier transform infrared spectroscopy (FTIR) and cyclic voltammetry (CV), respectively. The immobilized enzyme on nanoflake-like SnS2 retains its native structure and bioactivity and exhibits a surface-controlled, reversible two-proton and two-electron transfer reaction with the apparent electron transfer rate constant (k s) of 3.68s−1. The proposed biosensor shows fast amperometric response (8s) to glucose with a wide linear range from 2.5×10−5 M to 1.1×10−3 M, a low detection limit of 1.0×10−5 M at signal-to-noise of 3 and good sensitivity (7.6±0.5mAM−1 cm−2). The resulting biosensor has acceptable operational stability, good reproducibility and excellent selectivity and can be successfully applied in the reagentless glucose sensing at −0.45V. It should be worthwhile noting that it opens a new avenue for fabricating excellent electrochemical biosensor. [Copyright &y& Elsevier]