Copolymerizations of ethylene and 1-dodecene were conducted with a series of ansa-fluorenylamidodimethyltitanium complexes, [t-BuNSiMe2Flu]TiMe2（1a）, [t-BuNSiMe2（2,7-^tBu2Flu）]TiMe2（1 b）, and [（1-adamantyl）NSi...Copolymerizations of ethylene and 1-dodecene were conducted with a series of ansa-fluorenylamidodimethyltitanium complexes, [t-BuNSiMe2Flu]TiMe2（1a）, [t-BuNSiMe2（2,7-^tBu2Flu）]TiMe2（1 b）, and [（1-adamantyl）NSiMe2（2,7-^tBu2Flu）]TiMe2（1c） activated by modified methylaluminoxane. The activity increased by the introduction of the alkyl groups on the fluorenyl and amido ligands, and 1c produced the highest molecular weight copolymers. Complex 1c also promoted copolymerization of ethylene and ^iBu3 Al protected 10-undecen-1-ol with high activity（～2000 kg·mol^-1·h^-1）, affording hydroxy-functionalized ultrahigh molecular weight polyethylene. The hydroxy content of the copolymers obtained was controllable by changing comonomer feed ratio. The introduction of a small amount of hydroxy group can alter the surface properties of polyethylene.展开更多
Granular hydroxyl-functionalized UHMWPE was successfully prepared through copolymerization of ethylene and 10-undecen-1-ol protected by tri-iso-butylaluminum using a titanium complex.[tBuNSiMe_(2)(2,7-tBu2Flu)]TiMe_(2...Granular hydroxyl-functionalized UHMWPE was successfully prepared through copolymerization of ethylene and 10-undecen-1-ol protected by tri-iso-butylaluminum using a titanium complex.[tBuNSiMe_(2)(2,7-tBu2Flu)]TiMe_(2) was activated in hexane by silica-supported modified-methylaluminoxane.Without any additional pretreatments,the obtained polymer powders were transformed into fibers through a gel-spinning and heat drawing process.When compared to fibers generated from the equivalent unfunctionalized UHMWPE or the commercial HUMWPE,both creep resistance and hydrophilic properties were improved in the hydroxy-functionalized UHMWPE fibers without losing tensile strength.展开更多
基金financially supported by the National Natural Science Foundation of China (No. 21174026)Program for New Century Excellent Talents in University+3 种基金the Program for Professor of Special Appointment (Eastern Scholar) at Shanghai Institutions of Higher Learning"Shu Guang" project supported by Shanghai Municipal Education CommissionShanghai Education Development Foundationthe Fundamental Research Funds for the Central Universities (No. CUSF-DH-D-2017041)
文摘Copolymerizations of ethylene and 1-dodecene were conducted with a series of ansa-fluorenylamidodimethyltitanium complexes, [t-BuNSiMe2Flu]TiMe2（1a）, [t-BuNSiMe2（2,7-^tBu2Flu）]TiMe2（1 b）, and [（1-adamantyl）NSiMe2（2,7-^tBu2Flu）]TiMe2（1c） activated by modified methylaluminoxane. The activity increased by the introduction of the alkyl groups on the fluorenyl and amido ligands, and 1c produced the highest molecular weight copolymers. Complex 1c also promoted copolymerization of ethylene and ^iBu3 Al protected 10-undecen-1-ol with high activity（～2000 kg·mol^-1·h^-1）, affording hydroxy-functionalized ultrahigh molecular weight polyethylene. The hydroxy content of the copolymers obtained was controllable by changing comonomer feed ratio. The introduction of a small amount of hydroxy group can alter the surface properties of polyethylene.
基金This work was supported by the Fundamental Research Funds for the Central Universities(2232020A-05)National Natural Science Foundation of China(21174026)the Program for Professor of Special Appointment(Eastern Scholar)at Shanghai Institutions of Higher Learning.
文摘Granular hydroxyl-functionalized UHMWPE was successfully prepared through copolymerization of ethylene and 10-undecen-1-ol protected by tri-iso-butylaluminum using a titanium complex.[tBuNSiMe_(2)(2,7-tBu2Flu)]TiMe_(2) was activated in hexane by silica-supported modified-methylaluminoxane.Without any additional pretreatments,the obtained polymer powders were transformed into fibers through a gel-spinning and heat drawing process.When compared to fibers generated from the equivalent unfunctionalized UHMWPE or the commercial HUMWPE,both creep resistance and hydrophilic properties were improved in the hydroxy-functionalized UHMWPE fibers without losing tensile strength.
