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.
Haobo YuanCong LongJunrong YuFuyou KeTakeshi ShionoZhengguo Cai
Copolymerizations of ethylene and 1-dodecene were conducted with a series of ansa-fluorenylamidodimethyltitanium complexes, [t-BuNSiMe_2Flu]TiMe_2(1a), [t-BuNSiMe_2(2,7-~tBu_2Flu)]TiMe_2(1 b), and [(1-adamantyl)NSiMe_2(2,7-~tBu_2Flu)]TiMe_2(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 ~iBu_3 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.
