Font Size: a A A

Vinyl-addition Copolymerization Of Norbornene And Its Polar Derivatives By Catalytic System Based On Bis-(β-ketoamino)nickel(Ⅱ)

Posted on:2009-01-28Degree:MasterType:Thesis
Country:ChinaCandidate:M Q ChenFull Text:PDF
GTID:2121360278970914Subject:Materials Physics and Chemistry
Abstract/Summary:PDF Full Text Request
The research of the copolymerization of olefin and polar monomer catalyzed by late transition metal catalyst is an area of great recent interest in polyolefin material. The most common catalytic systems are the late transition metal nickel complex activated with cocatalyst MAO in recent literature.Because of MAO need special operation and storage,and plentiful MAO is need for high activity,but costly price affect its use.So it is expected to fred a kind of new cocatalyst which can replace MAO.The copolymerization of norbornene and its polar derivatives was carried out by using bis-(β-ketoamino)nickel(Ⅱ)/B(C6F5)3/AlEt3 as catalytic system in toluene. The activity of catalytic system,as well as the copolymerization behavior and law, were investigated.Polymerizations of 5-norbornene-2-yl-acetate in toluene were catalyzed by a new late transition metal complex catalytic system based on bis-(β-ketonaphthylamino)nickel(Ⅱ)/B(C6F5)3/AlEt3.The above catalytic system can polymerize 5-norbornene-2-yl-acetate in the range of 20-90℃and produced poly(5-norbornene-2-yl-acetate)s with moderate molecular weights(Mw = 7.0×103-3.1×104 g/mol) and relative narrow weight distributions(Mw/Mn=1.8-2.0). The obtained polymer was characterized by proton and carbon nuclear magnetic resonance,Fourier-transform infrared spectroscopy,differential scanning calorimetry, and wide-angle X-ray diffraction.Analysis results of nuclear magnetic resonance and Fourier-transform infrared spectroscopy indicated that the yielded polymer is vinyl poly(5-norbornene-2-yl-acetate),and demonstrated that the above catalytic system initiated 5-norbornene-2-yl-acetate polymerization according to the vinyl-addition mode.Wide-angle X-ray diffraction analysis result showed that poly(5-norbornene-2-yl-acetate) exhibit non-crystallinity but short-range order and long-range disorder, the interchain distances of the polymer is 1.24 nm.The polymer has better thermal stability(Td>330℃) and is soluble in many common solvents.Vinyl-type copolymerization of norbomene(NBE) and 5-norbornene-2-yl -acetate(NBE-OCOCH3) in toluene were investigated using a novel homogeneous catalyst system based on bis(β-ketonaphthylamino)Ni(Ⅱ)/B(C6F5)3/AlEt3.The above nickel(Ⅱ) complex bearing bis(β-ketonaphthylamino) ligand represent a new precatalyst can be activated by the co-catalytic system B(C6F5)3/AlEt3 and efficiently copolymerize norbornene with 5-norbomene-2-yl acetate in relative low yields,and to produce functionalized norbornene copolymer bearing ester functionalities with moderate molecular weight(Mw=1.9×104-2.7×104 g/mol) and narrow molecular weight distributions(Mw/Mn =1.5-1.9) of copolymer with variable contents of the methyl ester monomer unit.The copolymerization behavior as well as the copolymerization conditions,such as the levels of B(C6F5)3 and AlEt3,temperature, and monomer feed ratios,which influence on the copolymerization were examined. The achieved copolymers were confirmed to be vinyl-addition copolymers through the analysis of FTIR,1H NMR,and 13C NMR spectra.13C NMR studies further revealed the composition of the copolymer and the incorporation rate was 7.6-54.1 mol-%ester units at a content of 30-90 mol-%of the 5-norbomene-2-yl-acetate in the monomer feeds ratios.TGA analysis results showed that the copolymer exhibited good thermal stability(Td>410℃) and failed to observe the glass transitions temperature over 300℃.The copolymers are noncrystallinity by WAXD analysis results and show good solubility in common organic solvents.Copolymerization of norbornene and 5-norbornene-2-yl-methanol was carried out by using bis-(β-ketoamino)nickel(Ⅱ)/B(C6F5)3/AlEt3 as catalytic system in toluene.The influence of copolymerization conditions,such as Al/Ni,B/Ni molar ratio,polymerization temperature,polymerization time,and monomer feed ratio were investigated.The results indicated that above catalytic system can catalyze the copolymerization of norbornene with 5-norbornene-2-yl-methanol to yield higher molecular weight(Mw=5.97×104-5.37×105 g/mol) and incorporation ratio of 5-norbornene-2-yl-methanol(Mw/Mn=7%-55.4%).The obtained polymer was characterized by nuclear magnetic resonance,Fourier-transform infrared spectroscopy, thermal gravimetric analysis,differential scanning calorimetry,and wide-angle X-ray diffraction.The results of copolymer structure analysis demonstrated that the copolymerization of norbornene with 5-norbornene-2-yl-methanol runs vinyl-addition mode while catalyzed by above catalytic system.The copolymerization of norbornene and 5-norbornene-2-yl-methanol catalyzed by bis-(β-ketoamino)nickel(Ⅱ) catalytic system of different ligands with B(C6F5)3 and AlEt3 were investigated.The effect of catalytic activity and micro-structure of copolymer were investigated by catalyst with ligand of different steric hindrance and electronic effects.
Keywords/Search Tags:Bis-(β-ketonamino)nickel(II), Norbornene, Norbornene polar derivatives, Vinyl-addition copolymerization, Copolymer
PDF Full Text Request
Related items