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Abstract  

Pentaerythritol diphosphonate melamine-urea-formaldehyde resin salt, a novel cheap macromolecular intumescent flame retardants (IFR), was synthesized, and its structure was a caged bicyclic macromolecule containing phosphorus characterized by IR. Epoxy resins (EP) were modified with IFR to get the flame retardant EP, whose flammability and burning behavior were characterized by UL 94 and limiting oxygen index (LOI). 25 mass% of IFR were doped into EP to get 27.2 of LOI and UL 94 V-0. The thermal properties of epoxy resins containing IFR were investigated with thermogravimetry (TG) and differential thermogravimetry (DTG). Activation energy for the decomposition of samples was obtained using Kissinger equation. The resultant data show that for EP containing IFR, compared with EP, IFR decreased mass loss, thermal stability and R max, increased the char yield. The activation energy for the decomposition of EP is 230.4 kJ mol−1 while it becomes 193.8 kJ mol−1 for EP containing IFR, decreased by 36.6 kJ mol−1, which shows that IFR can catalyze decomposition and carbonization of EP.

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Abstract  

The radiation effect of γ-ray on polyether-urethane foam was studied. The gas products from irradiated samples were analyzed quantitatively and qualitatively by gas chromatography, the thermal property and radical intensity were determined by differential thermal gravimetry and electron spin resonance. The dynamic mechanical property, compression and tensile properties were analyzed. Positron annihilation lifetime of irradiated samples was also measured at room temperature in vacuum. The results show that the general mechanical properties of ETPU sample irradiated by γ-rays at a dose of 8.0·105 Gy is excellent, but there are considerable gas products and a great deal of radicals created, which indicates that the sample has been damaged by radiation. Relatively, the thermal stability of the sample remained fine.

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Abstract  

A microcalorimeter (Setaram c-80) was used to study the thermokinetics of the hydration process of calcium phosphate cement (CPC), a biocompatible biomaterial used in bone repair. The hydration enthalpy was determined to be 35.8 J g–1 at 37.0°C when up to 80 mg CPC was dissolved in 2 mL of citric buffer. In the present study, parameters related to time constants of the calorimeter were obtained by fitting the recorded thermal curves with the function θ=Ae–?t(1– e–?2t). The real thermogenetic curves were then retrieved with Tian function and the transformation rate of the hydration process of CPC was found to follow the equation α=1–[1–(0.0075t)3]3. The microstructures of the hydrated CPC were examined by scanning electron microscopy. The nano-scale flake microstructures are due to crystallization of calcium phosphate and they could contribute to the good biocompatibility and high bioactivity.

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Journal of Thermal Analysis and Calorimetry
Authors: Y. Y. Di, Z. C. Tan, L. W. Li, S. L. Gao, and L. X. Sun

Abstract

Low-temperature heat capacities of a solid complex Zn(Val)SO4·H2O(s) were measured by a precision automated adiabatic calorimeter over the temperature range between 78 and 373 K. The initial dehydration temperature of the coordination compound was determined to be, T D=327.05 K, by analysis of the heat-capacity curve. The experimental values of molar heat capacities were fitted to a polynomial equation of heat capacities (C p,m) with the reduced temperatures (x), [x=f (T)], by least square method. The polynomial fitted values of the molar heat capacities and fundamental thermodynamic functions of the complex relative to the standard reference temperature 298.15 K were given with the interval of 5 K.

Enthalpies of dissolution of the [ZnSO4·7H2O(s)+Val(s)] (Δsol H m,l 0) and the Zn(Val)SO4·H2O(s) (Δsol H m,2 0) in 100.00 mL of 2 mol dm−3 HCl(aq) at T=298.15 K were determined to be, Δsol H m,l 0=(94.588±0.025) kJ mol−1 and Δsol H m,2 0=–(46.118±0.055) kJ mol−1, by means of a homemade isoperibol solution–reaction calorimeter. The standard molar enthalpy of formation of the compound was determined as: Δf H m 0 (Zn(Val)SO4·H2O(s), 298.15 K)=–(1850.97±1.92) kJ mol−1, from the enthalpies of dissolution and other auxiliary thermodynamic data through a Hess thermochemical cycle. Furthermore, the reliability of the Hess thermochemical cycle was verified by comparing UV/Vis spectra and the refractive indexes of solution A (from dissolution of the [ZnSO4·7H2O(s)+Val(s)] mixture in 2 mol dm−3 hydrochloric acid) and solution A’ (from dissolution of the complex Zn(Val)SO4·H2O(s) in 2 mol dm−3 hydrochloric acid).

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Abstract  

The characterization of different sized TiO2 (25 nm, 80 nm, and 155 nm) was carried out by transmission electron microscopy (TEM) and the micro-distributions of TiO2 in the olfactory bulb of mice after nasal inhalation were investigated by microbeam SRXRF mapping techniques. The results show that TiO2 particles can be translocated to the olfactory bulb through the olfactory nerve system after inhalation. The distributions of Fe, Cu, and Zn in the olfactory bulb were also studied.

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Acta Alimentaria
Authors: S. Hu, H. Shu, J.L. Yuan, J.Y. Gao, P.Y. Mu, C.Z. Ren, W. Sang, L.C. Guo, and H.B. Chen

The objective of this study was to evaluate the effect of wheat–oat flour ratio on the physical properties and β-glucan characteristics of extrudates. Results showed that increasing the wheat–oat flour ratio resulted in a decrease in the water solubility index (r2=0.8567) and hardness (r2=0.9316), whereas the expansion ratio (r2=0.9307) and water absorption index (r2=0.9061) increased. Wheat flour generally caused an increase in L values from 57.81 to 62.94 providing bright samples. Few cells were observed at high wheat–oat flour ratios under a scanning electron microscope, and a smooth surface was noted. Meanwhile, the total (r2=0.9867) and soluble (r2=0.9848) β-glucan contents were inversely proportional to the wheat–oat flour ratio. Extrudates with added wheat flour had a high molecular weight, but wheat flour had no significant (P<0.05) effect on the viscosity of β-glucan extracts. Conclusively, incorporation of wheat flour at a wheat–oat flour ratio of 2.33 provides ready-to-eat food based on whole oat flour, on account of improving the texture and providing sufficient β-glucan contents (0.806 g/100 g) without significantly affecting β-glucan viscosity.

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