The influence of temperature and mass fraction of Pluonic F127 on the rheological properties of polyvinyl butyric （PVB）/Pluronic F127/polyethylene glycol （PEG） 200 blend systems was investigated by a rotational rh...The influence of temperature and mass fraction of Pluonic F127 on the rheological properties of polyvinyl butyric （PVB）/Pluronic F127/polyethylene glycol （PEG） 200 blend systems was investigated by a rotational rheometer with parallel plates. The results show that the blend systems approach homogeneous state at 140, 150 and 160℃while the rheological properties of the blend systems significantly deviate from the homogeneous systems at 120℃. Shear thinning behavior is observed for all the blend systems at different temperatures and is enhanced by increasing Pluronic F127 content. The complex viscosity, storage modulus, loss modulus, zero-shear activation energy and flow recovery of the blend systems increase with the increase of Pluronic F127 content. There is a crossing point for the loss modulus and the storage modulus of each sample at high frequency, which is called specified frequency （SF）. The loss modulus is larger than the storage modulus when the frequency is less than the SF, and when frequency is more than SF, the loss modulus is smaller than the storage modulus.展开更多
Niobium(V) ethoxide(Nb(OEt)5) was synthesized by electrochemical reaction of ethanol with niobium plate as the sacrificial anode,stainless steel as the cathode and tetraethylammonium chloride(TEAC) as the conductive a...Niobium(V) ethoxide(Nb(OEt)5) was synthesized by electrochemical reaction of ethanol with niobium plate as the sacrificial anode,stainless steel as the cathode and tetraethylammonium chloride(TEAC) as the conductive additive.The condensates were isolated by vacuum distillation under 5 kPa.The product was characterized by Fourier transform infrared(FT-IR) spectra,Raman spectra and nuclear magnetic resonance(NMR) spectra.The results indicate that the product is niobium ethoxide.Thermal properties of niobium ethoxide were analysed by TG/DTG.Vapour pressure was calculated from the Langmuir equation and the enthalpy of vaporization was calculated from the vapour pressure-temperature data using the Clausius-Clapeyron equation.The concentrations of impurity metallic elements in the sample were detected by ICP-MS.It is shown that the purity can reach 99.997%.The volatility and purity of the niobium ethoxide ensure that it could be a good precursor for chemical vapor deposition and atomic layer deposition of niobium oxide layers.展开更多
基金Project(20776161) supported by the National Natural Science Foundation of China
文摘The influence of temperature and mass fraction of Pluonic F127 on the rheological properties of polyvinyl butyric （PVB）/Pluronic F127/polyethylene glycol （PEG） 200 blend systems was investigated by a rotational rheometer with parallel plates. The results show that the blend systems approach homogeneous state at 140, 150 and 160℃while the rheological properties of the blend systems significantly deviate from the homogeneous systems at 120℃. Shear thinning behavior is observed for all the blend systems at different temperatures and is enhanced by increasing Pluronic F127 content. The complex viscosity, storage modulus, loss modulus, zero-shear activation energy and flow recovery of the blend systems increase with the increase of Pluronic F127 content. There is a crossing point for the loss modulus and the storage modulus of each sample at high frequency, which is called specified frequency （SF）. The loss modulus is larger than the storage modulus when the frequency is less than the SF, and when frequency is more than SF, the loss modulus is smaller than the storage modulus.
基金Project(2007AA03Z425) supported by the National Hi-tech Research and Development Program of ChinaProject(50404011) supported by the National Natural Science Foundation of China
文摘Niobium(V) ethoxide(Nb(OEt)5) was synthesized by electrochemical reaction of ethanol with niobium plate as the sacrificial anode,stainless steel as the cathode and tetraethylammonium chloride(TEAC) as the conductive additive.The condensates were isolated by vacuum distillation under 5 kPa.The product was characterized by Fourier transform infrared(FT-IR) spectra,Raman spectra and nuclear magnetic resonance(NMR) spectra.The results indicate that the product is niobium ethoxide.Thermal properties of niobium ethoxide were analysed by TG/DTG.Vapour pressure was calculated from the Langmuir equation and the enthalpy of vaporization was calculated from the vapour pressure-temperature data using the Clausius-Clapeyron equation.The concentrations of impurity metallic elements in the sample were detected by ICP-MS.It is shown that the purity can reach 99.997%.The volatility and purity of the niobium ethoxide ensure that it could be a good precursor for chemical vapor deposition and atomic layer deposition of niobium oxide layers.
