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
C\-\{60\}\|end\|bonded polystryrenes(PS\|C\-\{60\}\|Br) with narrow molecular weight polydispersity were prepared by atom transfer radical polymerization (ATRP) in good yield.GPC results show that the polydispersities...C\-\{60\}\|end\|bonded polystryrenes(PS\|C\-\{60\}\|Br) with narrow molecular weight polydispersity were prepared by atom transfer radical polymerization (ATRP) in good yield.GPC results show that the polydispersities of these fullerene polymeric derivatives were between 1.1 and 1.3.The brown color of the solution indicates that C\-\{60\} has been bonded into the polymer,which was confirm by UV\|vis.Furthermore,2\|amino\|acetonictrile was used as an IR label to react with PS\|C\-\{60\}\|Br,and the product show the characteristic absorption of CN group at 2369cm\+\{-1\}.These results reinforce the conclusion that C\-\{60\} has been covalently bonded into the polymer.A possible mechanism of the formation of C\-\{60\}\|end\|bonded PSt was deduced tentatively.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.
文摘C\-\{60\}\|end\|bonded polystryrenes(PS\|C\-\{60\}\|Br) with narrow molecular weight polydispersity were prepared by atom transfer radical polymerization (ATRP) in good yield.GPC results show that the polydispersities of these fullerene polymeric derivatives were between 1.1 and 1.3.The brown color of the solution indicates that C\-\{60\} has been bonded into the polymer,which was confirm by UV\|vis.Furthermore,2\|amino\|acetonictrile was used as an IR label to react with PS\|C\-\{60\}\|Br,and the product show the characteristic absorption of CN group at 2369cm\+\{-1\}.These results reinforce the conclusion that C\-\{60\} has been covalently bonded into the polymer.A possible mechanism of the formation of C\-\{60\}\|end\|bonded PSt was deduced tentatively.
