Several bis（trifluoromethylsulfonyl）phenylamines have been synthesized and used as internal donors for the preparation of heterogeneous Ziegler-Natta catalysts for propylene polymerization. These new cata- lysts are...Several bis（trifluoromethylsulfonyl）phenylamines have been synthesized and used as internal donors for the preparation of heterogeneous Ziegler-Natta catalysts for propylene polymerization. These new cata- lysts are highly active and stereospecific in combination with an external donor for the polymerization of propylene. The activity of these catalysts is dramatically influenced by the electronic capability of the phenyl substituents on the sulfonyl phenylamines. Therefore, the performances of the catalysts can be modified by adjusting the electronic property of the phenyl substituents of the sulfonyl phenylamines.展开更多
Novel MgCl2-supported Ziegler-Natta (Z-N) catalysts prepared using a new one-pot ball milling method can effectively control the amounts of Ti-loading in the catalysts. Complex GPC data on polypropylene synthesized by...Novel MgCl2-supported Ziegler-Natta (Z-N) catalysts prepared using a new one-pot ball milling method can effectively control the amounts of Ti-loading in the catalysts. Complex GPC data on polypropylene synthesized by these novel catalysts were analyzed using the method of fitting the molecular weight distribution (MWD) curves with a multiple Flory-Schulz function. It was found that multiple active centers exist in these novel catalysts. Detailed study of the effects of the Ti-loadings in the catalysts on the distribution of the active centers showed that the Ti-loadings in the novel MgCl2-supported Z-N catalysts might affect the proportion of each type of active centers; and might be the main factor responsible for the effect of the Ti-loadings on the microstructure, the molecular weight and molecular weight distribution width of the resultant polymer, the catalytic activity and polymerization kinetics.展开更多
A P-substituted sulfonyl-containing compound was synthesized in the lab. The structure of the compound was demonstrated by 1H and 31P NMR. The propylene polymerization catalysts were prepared by incorporating an inter...A P-substituted sulfonyl-containing compound was synthesized in the lab. The structure of the compound was demonstrated by 1H and 31P NMR. The propylene polymerization catalysts were prepared by incorporating an internal donor, and the content of Ti, H and C in the catalysts was also checked by elemental analysis. The effect of dosage of the donor, the Al/Ti ratio and the polymerization temperature on the catalyst activity were studied, the results suggested that the dosage of donor, the Al/Ti ratio and the polymerization temperature could affect not only the activity of catalyst but also the isotacticity index of the polymer. A catalyst with high activity was selected, and the polypropylene formed in the presence of this catalyst had high isotacticity index.展开更多
A novel MgCl2-supported Ziegler-Natta catalyst containing diethyl diisopropylsuccinate donor was prepared and propylene polymerizations with the combination of such catalyst and four external donors were investigated ...A novel MgCl2-supported Ziegler-Natta catalyst containing diethyl diisopropylsuccinate donor was prepared and propylene polymerizations with the combination of such catalyst and four external donors were investigated in detail. The catalyst was compared with a commercial one with phthalate as internal donor in terms of catalytic activity, hydrogen sensitivity and stereospecificity in propylene polymerization. The molecular weight,molecular weight distribution and microstructure of the produced polypropylenes were compared also. It was found that the novel catalyst containing succinate internal donor showed higher activity and higher stereospecificity than those with phthalate as internal donor. Consequently, polypropylenes obtained by the succinate-based catalyst showed high molecular weight, high melting temperature, high isotactic index and broad molecular weight distribution than those obtained with the commercial catalyst.展开更多
Poly （methyl methacrylate） （PMMA） brushes were synthesized from silicon wafers via surface initiated atom transfer radical polymerization （SI-ATRP）. Energy disperse spectroscopy （EDS） and atomic force microsco...Poly （methyl methacrylate） （PMMA） brushes were synthesized from silicon wafers via surface initiated atom transfer radical polymerization （SI-ATRP）. Energy disperse spectroscopy （EDS） and atomic force microscopy （AFM） confirmed that PMMA brushes were successfully prepared on the silicon wafers, and the surface became more hydrophobic according to the contact angle of 69~. It is found that CuCI/1, 1, 4, 7, 10, 10-hexamethyl triethylenetetramine （HMTETA） system is more suitable than CuBr/N, N, N′, N″, N′″-pentamethyl diethylenetriamine （PMDETA） system to control the free radical polymerization of MMA in solution. Nevertheless, better control on the thickness of PMMA brushes was achieved in CuBr/PMDETA than in CuC1/HMTETA due to higher activity and better reversibility of the former system.展开更多
Synthesis and anionic polymerization of the fluorine-substituted phenyl methacrylates are herein reported. A series of monodi-, and multi-substituted fluorophenyl methacrylates H2C=C（CH3）C（O）OC6H4F-4 （M^1a）, H2...Synthesis and anionic polymerization of the fluorine-substituted phenyl methacrylates are herein reported. A series of monodi-, and multi-substituted fluorophenyl methacrylates H2C=C（CH3）C（O）OC6H4F-4 （M^1a）, H2C=C（CH3）C（O）OC6H4F-3 （M^1b）, HEC=C（CH3）C（O）OC6H3F2-2,4 （M^2）, H2C=C（CH3）C（O）OC6H2F3-2,3,4 （M^3）, H2C=C（CH3）C（O）OC6HF4-2,3,5,6 （M^4）, and H2C=C（CH3）C（O）OC6F5 （M^5） were synthesized and characterized. Initially, the polymerization was carded out on the monomer M^1a by using nBuLi, tBuLi, and KH as the respective catalysts; this approach produced the polymers in yields of 12%-50%, but with lower molecular weights. Similar results were obtained by using tBuLi for catalytically polymerizing the other five monomers. By introducing a co-catalyst MeAl（BHT）2, the catalysts Nail, LiH, and tBuOLi each were tested to polymerize M^1a, which gave the polymers in very low yields （3%-7%）. Polymer yields of 13%-27% were obtained by each of the catalysts LiAlH4, nBuLi, PhLi, and tBuLi in connection with MeAI（BHT）2, but a better yield （61%） was achieved with KH/MeAl（BHT）2. The KH/MeAl（BHT）2 catalyst system was further employed to polymerize M^1b and M^2, which afforded respective polymer yields of 12%-63% and 10%-53%, depending on the molar ratios of KH：MeAl（BHT）2 as well as on the monomer concentrations. All of the polymers produced were syndiotactically rich in structure, as indicated by either ^1H or ^19F NMR data. The polymerization mechanism by the combined catalyst system is proposed.展开更多
文摘Several bis（trifluoromethylsulfonyl）phenylamines have been synthesized and used as internal donors for the preparation of heterogeneous Ziegler-Natta catalysts for propylene polymerization. These new cata- lysts are highly active and stereospecific in combination with an external donor for the polymerization of propylene. The activity of these catalysts is dramatically influenced by the electronic capability of the phenyl substituents on the sulfonyl phenylamines. Therefore, the performances of the catalysts can be modified by adjusting the electronic property of the phenyl substituents of the sulfonyl phenylamines.
基金Project supported by the National Natural Science Foundation ofChina (No. 20172045) Science and Technology Plan Fund of Zhe-jiang Province (No. 001101116) and Foundation for Doctors ofNingbo City (No. 2003A62012) China
文摘Novel MgCl2-supported Ziegler-Natta (Z-N) catalysts prepared using a new one-pot ball milling method can effectively control the amounts of Ti-loading in the catalysts. Complex GPC data on polypropylene synthesized by these novel catalysts were analyzed using the method of fitting the molecular weight distribution (MWD) curves with a multiple Flory-Schulz function. It was found that multiple active centers exist in these novel catalysts. Detailed study of the effects of the Ti-loadings in the catalysts on the distribution of the active centers showed that the Ti-loadings in the novel MgCl2-supported Z-N catalysts might affect the proportion of each type of active centers; and might be the main factor responsible for the effect of the Ti-loadings on the microstructure, the molecular weight and molecular weight distribution width of the resultant polymer, the catalytic activity and polymerization kinetics.
基金the PetroChina Science & Technology Management Department for the financial support (No.2010F-19)
文摘A P-substituted sulfonyl-containing compound was synthesized in the lab. The structure of the compound was demonstrated by 1H and 31P NMR. The propylene polymerization catalysts were prepared by incorporating an internal donor, and the content of Ti, H and C in the catalysts was also checked by elemental analysis. The effect of dosage of the donor, the Al/Ti ratio and the polymerization temperature on the catalyst activity were studied, the results suggested that the dosage of donor, the Al/Ti ratio and the polymerization temperature could affect not only the activity of catalyst but also the isotacticity index of the polymer. A catalyst with high activity was selected, and the polypropylene formed in the presence of this catalyst had high isotacticity index.
文摘A novel MgCl2-supported Ziegler-Natta catalyst containing diethyl diisopropylsuccinate donor was prepared and propylene polymerizations with the combination of such catalyst and four external donors were investigated in detail. The catalyst was compared with a commercial one with phthalate as internal donor in terms of catalytic activity, hydrogen sensitivity and stereospecificity in propylene polymerization. The molecular weight,molecular weight distribution and microstructure of the produced polypropylenes were compared also. It was found that the novel catalyst containing succinate internal donor showed higher activity and higher stereospecificity than those with phthalate as internal donor. Consequently, polypropylenes obtained by the succinate-based catalyst showed high molecular weight, high melting temperature, high isotactic index and broad molecular weight distribution than those obtained with the commercial catalyst.
基金Project(21376271)supported by the National Natural Science Foundation of ChinaProject(2013)supported by the Scientific Research Foundation for the Returned Overseas Chinese Scholars,China+2 种基金Projects(CL12129,201310533008)supported by the Undergraduates Innovative Training Foundation of Central South University,ChinaProject(Z12060)supported by the Undergraduate Free Exploration Innovation Foundation of Central South University,ChinaProject(CSUZC2013008)supported by the Open-End Fund for the Valuable and Precision Instruments of Central South University,China
文摘Poly （methyl methacrylate） （PMMA） brushes were synthesized from silicon wafers via surface initiated atom transfer radical polymerization （SI-ATRP）. Energy disperse spectroscopy （EDS） and atomic force microscopy （AFM） confirmed that PMMA brushes were successfully prepared on the silicon wafers, and the surface became more hydrophobic according to the contact angle of 69~. It is found that CuCI/1, 1, 4, 7, 10, 10-hexamethyl triethylenetetramine （HMTETA） system is more suitable than CuBr/N, N, N′, N″, N′″-pentamethyl diethylenetriamine （PMDETA） system to control the free radical polymerization of MMA in solution. Nevertheless, better control on the thickness of PMMA brushes was achieved in CuBr/PMDETA than in CuC1/HMTETA due to higher activity and better reversibility of the former system.
基金supported by the National Basic Research Program of China(2012CB821704)the National Natural Science Foundation of China(20972129)the Innovative Research Team Program(IRT1036,J1310024)
文摘Synthesis and anionic polymerization of the fluorine-substituted phenyl methacrylates are herein reported. A series of monodi-, and multi-substituted fluorophenyl methacrylates H2C=C（CH3）C（O）OC6H4F-4 （M^1a）, H2C=C（CH3）C（O）OC6H4F-3 （M^1b）, HEC=C（CH3）C（O）OC6H3F2-2,4 （M^2）, H2C=C（CH3）C（O）OC6H2F3-2,3,4 （M^3）, H2C=C（CH3）C（O）OC6HF4-2,3,5,6 （M^4）, and H2C=C（CH3）C（O）OC6F5 （M^5） were synthesized and characterized. Initially, the polymerization was carded out on the monomer M^1a by using nBuLi, tBuLi, and KH as the respective catalysts; this approach produced the polymers in yields of 12%-50%, but with lower molecular weights. Similar results were obtained by using tBuLi for catalytically polymerizing the other five monomers. By introducing a co-catalyst MeAl（BHT）2, the catalysts Nail, LiH, and tBuOLi each were tested to polymerize M^1a, which gave the polymers in very low yields （3%-7%）. Polymer yields of 13%-27% were obtained by each of the catalysts LiAlH4, nBuLi, PhLi, and tBuLi in connection with MeAI（BHT）2, but a better yield （61%） was achieved with KH/MeAl（BHT）2. The KH/MeAl（BHT）2 catalyst system was further employed to polymerize M^1b and M^2, which afforded respective polymer yields of 12%-63% and 10%-53%, depending on the molar ratios of KH：MeAl（BHT）2 as well as on the monomer concentrations. All of the polymers produced were syndiotactically rich in structure, as indicated by either ^1H or ^19F NMR data. The polymerization mechanism by the combined catalyst system is proposed.
