Studies On Olefins Polymerization Catalyzed By Mono-cyclopentadienyl-titanium Complex CatalyticSystem

Metallocene polyethylene is the copolymer (mLLDPE) of ethylene andα-olefins with a metallocene catalyst system. mLLDPE have been focused on thedevelopment of metallocene catalyst. The variety of mLLDPE developed ware bestmore than that of other metallocene polymers. In update technologic evolvement ofthe metallocene-polyproylenes , the metallocene catalyst developed by ATOFINAand metallocene catalyst developed by Basell extend the potential application ofmetallocene-polyproylene markets. the metallocene catalyst developed by ATOFINAis used to synthesize atactic copolymer , and that by Basell to synthesize atacticcopolymer and impact copolymer. Especially, the recent cooperation of Basell andExxonMobil shall promote the development and industries process of metalloceneatactic copolymer and metallocene impact copolymer. In this article, our works areas follows:1, Synthesis of A Novel Zirconocene Complex (1, 2-Ph2-4-MeCp)2ZrMe2) andcatalysis For Ethylene Polymerization .A new metelloene complex , (1,2-Ph2-4-MeCp)2ZrMe2, was synthesized using 3, 4-diphenyl-1-cyclopentenone ,methyl lithium, n-butyl lithium, and ZrCl4 as feedstock through a series of properreactions. The structure of the complex was characterized and determined by elementanalysis, 1H NMR, 13C NMR, and X-ray crystal structure analysis. Contrast to MAO,the result of ethylene polymerization showed that, Upon activation withAl(iBu)3/Ph3C+B(C6F5)4?, the complex effectively polymerized ethylene at lowerAl/Zr ratios and high molecular weight polyethylene with high melting transitiontemperatures was produced.2, Copolymerization of ethylene with dicyclopentadiene using novelConstrained Geometry Catalyst. The copolymerization of ethylene anddicyclopentadiene (DCP) using a novel CGC catalyst [2, 4-tBu2-6-(2, 3, 4,5-Me4-Cp)-PhO]TiCl2 combined with Al(iBu)3/Ph3C+B(C6F5)4-as cocatalyst systems,was studied. Complete characterizations of the copolymers were carried out with1H-NMR, 13C-NMR, differential scanning calormetry (DSC), SEM and X-ray. Theanalysis results showed that the copolymers of the ethylene and dicyclopentadienewere amorphous, and displayed two melting temperatures in a wide range ofcomonomer contents. Moreover, the morphology of the copolymers is much differentfrom polyethylenes.3. Propylene Polymerization Catalyzed by Constrained GeometryCyclopentadienyl-phenoxytitanium Catalysts. Propylene polymerization wasperformed using three constrained geometry catalysts:2-(tetramethylcyclopentadienyl)-4, 6-di-tert-butylphenoxytitanium dichloride (1),2-(tetramethylcyclopentadienyl)-6-tert-butylphenoxytitanium dichloride (2), and2-(tetramethylcyclopentadienyl)-6-phenylphenoxytitanium dichloride (3) withAl(iBu)3/[Ph3C]+[B(PhF5)]4-as co-catalyst. The substituent effect of the ligand and theeffect of Al/Ti molar ratio on the catalytic properties were investigated. The catalyticactivity increases in the order of 1 > 2 > 3. The microstructure of the polypropylenesamples was analyzed by 13C NMR spectroscopy. The 13C NMR results show that thepolymers are basically atactic polypropylene with some 2,1-insertion and1,3-enchainment units in the polymer chain, and the end groups are mainlyvinylidene(CH2=CMe-) and vinyl(CH2=CH-) together with small amount of propenyl(CH3CH=CH-). A possible chain propagation and termination mechanism of thepropylene polymerization was discussed.4, Synthesis and polymerization of Nonbridged cyclopentadienyl Titanium(Ⅳ)Aryloxide complexes of the CpT?i(OAr)X2 for producing Higher molecular weightatactic polypropylene. two Nonbridged Titanium(Ⅳ ) cyclopentadienyl-Aryloxycomplexes such as 1,2-Ph-2-4-methyl –cyclopentadieny-2,4,6-tBu3-AryloxyTitanium( Ⅳ ) dichloride (3) and 1-Ph-2,3,4,5-Me4 –cyclopentadieny-2,4,6-tBu3-Aryloxy Titanium( Ⅳ ) dichloride (4) could be prepared in high yields fromCp*TiCI3(Cp*=cyclopentadienyl).When activated by Al(iBut)3-Ph3C+B(C6F5)4–cocatalyst, two complexes show higher catalytic activities for propylenepolymerization. An influence of Ai/Ti radio and temperature on the catalytic activityand the polymer molecular weight was investigated. The results show that highermolecular weight(Mw=8-20×104) atactic polypropylene could be produced inpropylene polymerization at lower Al/Ti(mol) radios and at commercial temperature.5, Studies of synthesis of aPP-iPP polypropylene blends in in situpolymerization with Ziegler-Natta and metallocene catalyst systems. Propylenepolymerization was carried out with a sequence addition of metallocene CAT/Al(iBu)3/[Ph3C]+[B(PhF5)]4-catalytic system and Ziegler-Natta catalyst MTC/TEAcatalytic system at 70oC in 250 ml steel autoclave with a magnetic stirrer. Thepolypropylene obtained is a blends comprising of atactic polypropylene and isotacticpolypropylene. The polypropylene with different properties can be obtained byadjusting ratio of CAT/ MTC. The range of polypropylene properties are: molecularweight Mw= 6.2-25×10-4,crystal temperature Tc=107-116°C, melting temperatureTm=52-55°C,mmmm=52-60%。6, Studies on synthesis of impact polypropylene "alloy" in in situpolymerization. The synthesis of impact polypropylene "alloy" were performed withconventional Ziegler-Natta DQ/TEA system and metallocene CAT/Al(iBu)3/[Ph3C]+[B(PhF5)]4-catalytic system at 70oC in 5L steel autoclave with amechanism stirrer. The effect of reaction time on the form of polymer "calloy", andthe effect of the ratio of catalyst on the form and properties of polymer "calloy" aswell as the influence of "calloy" catalyst system on the sensitivity of hydrogen areinvestigated. The test of synthesizing polymer "calloy" has been repented. Theproperties and characterization of polymer "calloy" are characterized and tested. Theresults show that the structure of polymer "calloy" has the character of "core-shell"structure and the impact intensity of polymer "calloy" is 2-4time higher than that ofpolymer obtained only by conventional Ziegler-Natta DQ/TEA system. propertiesand characterization of polymer "calloy" can be improved by adjusting the ratio ofZiegler-Natta DQ catalyst and metallocene CAT catalyst. The results also show thatthe polymer "calloy" obtained in adjustable technology variable all have a toughnesscharacteristic.7, Studies on copolymerization of ethylene/1-hexene, ethylene/1-decene. Thecopolymerization of ethylene/1-hexene, ethylene/1-decene were performed withtwo2-(tetramethylcyclopentadienyl)-4, 6-di-tert-butylphenoxy -titanium dichloride (1),2-(tetramethylcyclopentadienyl)-6-tert-butylphenoxytitanium dichloride (2) andAl(iBu)3/[Ph3C]+[B(PhF5)]4-catalytic systems. The effect of the concentration ofcomonomer on the catalytic activity, and molecular weight of copolymer and on thecontent of monomer in copolymer were investigated. The copolymer wascharacterized by NMR spectrum. The results show that two different catalytic systemsware not great difference in copolymerization for ethylene/1-hexene,ethylene/1-decene. The catalytic activity for ethylene/1-hexene copolymerization ishigher than that for ethylene/1-decene copolymerization. The molecular weight andmelting temperature of copolymer, and the content of comonomer in copolymer forethylene/1-hexene copolymerization were higher than that for ethylene/1-decenecopolymerization. By triad sequence distribution and statistical analysis, The chainpropagation process of copolymer accord with first order Markovian chainpropagation mechanism. P21>0.5 and P12 <0.5 of probability parameter indicatedthat the distribution of comonomer in copolymer chain ware feature of randomdistribution for ethylene/1-hexene copolymer.