A diphenoxybis(β diketonato)titanium complex, (dbm) 2Ti(OPh) 2, was synthesized and the corresponding MgCl 2\|supported catalyst was prepared by impregnation method. The polymerization activity was drastically improv...A diphenoxybis(β diketonato)titanium complex, (dbm) 2Ti(OPh) 2, was synthesized and the corresponding MgCl 2\|supported catalyst was prepared by impregnation method. The polymerization activity was drastically improved by using MgCl 2\|supported (dbm) 2Ti(OPh) 2 activated by aluminoxane (MAO) for ethylene polymerization (1.5×10 5 g/molTi with the heterogeneous catalyst and 1.3×10\+3 g/molTi with the homogeneous one). When the molar ratio of Al to Ti increased from 50 to 1000, the crystallinity and molecular weight of polyethylene were decreased rapidly. Also, the molecular weight of polyethylene was decreased from 5.1×10 5 to 2.8×10\+5 by increasing the molar content of titanium of the supported catalyst from 0.5×10 -5 to 3.42 ×10 -5 . After 60 min of the reaction, the molecular weight was at 5.0×10 5 or so. It is revealed that the MgCl 2\|supported β diketonato titanium complex is influenced by the polymerization conditions markedly.展开更多
The crystallization behavior and kinetics of CaO-MgO-Al2O3 SiO2（CMAS） glass with the Fe2O3 content ranging from zero to 5%were investigated by differential scanning calorimetry（DSC）.The structure and phase analyse...The crystallization behavior and kinetics of CaO-MgO-Al2O3 SiO2（CMAS） glass with the Fe2O3 content ranging from zero to 5%were investigated by differential scanning calorimetry（DSC）.The structure and phase analyses were made by Fourier transform infrared spectroscopy（FT-IR） and X-ray diffraction（XRD）.The experiment results show that the endothermic peak temperature about 760℃ is associated with transition and the exothermic peak temperature about 1000℃ is associated with crystallization.The crystallization peak temperature decreases with increasing the Fe203 content.The crystallization mechanism is changed from two-dimensional crystallization to one-dimensional growth,and the intensity of diopside peaks becomes stronger gradually.There is a saltation for the crystallization temperature with the addition of 0.5%Fe2O3 due to the decomposition of Fe2O3.Si-O-Si,O-Si-O and T-O-T（T=Si,Fe,Al） linkages are observed in Fe2O3-CaO-MgO-Al2O3-SiO2 glass.展开更多
文摘A diphenoxybis(β diketonato)titanium complex, (dbm) 2Ti(OPh) 2, was synthesized and the corresponding MgCl 2\|supported catalyst was prepared by impregnation method. The polymerization activity was drastically improved by using MgCl 2\|supported (dbm) 2Ti(OPh) 2 activated by aluminoxane (MAO) for ethylene polymerization (1.5×10 5 g/molTi with the heterogeneous catalyst and 1.3×10\+3 g/molTi with the homogeneous one). When the molar ratio of Al to Ti increased from 50 to 1000, the crystallinity and molecular weight of polyethylene were decreased rapidly. Also, the molecular weight of polyethylene was decreased from 5.1×10 5 to 2.8×10\+5 by increasing the molar content of titanium of the supported catalyst from 0.5×10 -5 to 3.42 ×10 -5 . After 60 min of the reaction, the molecular weight was at 5.0×10 5 or so. It is revealed that the MgCl 2\|supported β diketonato titanium complex is influenced by the polymerization conditions markedly.
基金Projects(51264023,51364020,U1202271)supported by the National Natural Science Foundation of ChinaProject(IRT1250)supported by the Program for Innovative Research Team in University of Ministry of Education of ChinaProject(2014HA003)supported by the Science and Technology Leading Talent of Yunnan Province,China
文摘The crystallization behavior and kinetics of CaO-MgO-Al2O3 SiO2（CMAS） glass with the Fe2O3 content ranging from zero to 5%were investigated by differential scanning calorimetry（DSC）.The structure and phase analyses were made by Fourier transform infrared spectroscopy（FT-IR） and X-ray diffraction（XRD）.The experiment results show that the endothermic peak temperature about 760℃ is associated with transition and the exothermic peak temperature about 1000℃ is associated with crystallization.The crystallization peak temperature decreases with increasing the Fe203 content.The crystallization mechanism is changed from two-dimensional crystallization to one-dimensional growth,and the intensity of diopside peaks becomes stronger gradually.There is a saltation for the crystallization temperature with the addition of 0.5%Fe2O3 due to the decomposition of Fe2O3.Si-O-Si,O-Si-O and T-O-T（T=Si,Fe,Al） linkages are observed in Fe2O3-CaO-MgO-Al2O3-SiO2 glass.
