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 Rmax, 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.
Authors:W. Huang, Y. Xu, X. Chen, X. Gao, and Y. Fu
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.
Authors:W.Y. Gao, Y.W. Wang, L.M. Dong, and Z.W. Yu1
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
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.
Authors:Y. Y. Di, Z. C. Tan, L. W. Li, S. L. Gao, and L. X. Sun
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, TD=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 (Cp,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)] (ΔsolHm,l0) and the Zn(Val)SO4·H2O(s) (ΔsolHm,20) in 100.00 mL of 2 mol dm−3 HCl(aq) at T=298.15 K were determined to be, ΔsolHm,l0=(94.588±0.025) kJ mol−1 and ΔsolHm,20=–(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: ΔfHm0 (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).
Authors:J. Wang, C. Chen, H. Yu, J. Sun, B. Li, Y. Li, Y. Gao, W. He, Y. Huang, Z. Chai, Y. Zhao, X. Deng, and H. Sun
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.
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.