ESR和NMR在茂金属催化剂和聚烯烃研究中的应用

波谱学杂志第20卷第2期Vol. 20 No.22003年6月Chinese Jourmal of Magnetic ResonanceJun. 2003文章编号1000-4556( 2003 )02-0187-13APPLICATION OF ESR AND NMR TO INVESTIGATIONOF METALLOCENE CATALYST AND POLYOLEFINWANG Wen-qin , WANG Li* , WANG Jian-feng , MA Zhen-li( Department of Polymer Science and Engineering , Zhejiang University , Hangzhou 310027 , China )Abstract : With the rapid development of polymer science and catalysis technology , it has become more andmore important to understand the microstructures of polymer and catalyst. In the paper , the recent applica-tions of ESR and NMR in studying metallocene catalyst and polyolefin are reviewed. The results suggest thatthe ESR and NMR techniques useful research tools in studying the microstructure of polymers and catalysts.Key words : ESR , NMR , meallocene , polyolefin , microtucture informationCLC number :0482.53Document code : AINTRODUCTIONIn recent years there have been a large number of studies on Ziegler- Natta and metallocene cat-alysts for polyolefin synthesis 1-31. A vast amount of information on catalytic mechanisms has beenobtained for the olefin polymerization reactions catalyzed by these systemt 45]. However , usually itis more difficult to investigate the coordination structure of the transition metal species during olefinpolymerization. Fortunately , if the transition metal in the catalytic system has an unpaired electron ,the system can be monitored by electron spin resonance ( ESR ) technique , as indicated in severalreports 5-9] , and the segment motion of resultant polymers can be studied by spin probe method. Inaddition , for improving property of the resultant polymer products ,it is very necessary to acquire themicrostructure中国煤化工Received date : 18 Nov .2002 ; Revised date :30 Dee.CNMHGFoundation item :National Natural Science Foundation (MYHBiography :Wang Wen-qin 1974- ), male , WeiFang of Shandong. Now he is starting his Ph. D. working in the Department ofPolymer Science and Engineering of Zhejiang University . The research area of his Ph. D. is the polymer-supportedmetallocene catalyst for olefin polymerization.* Crrespondence author : Tel 0571 - 87952400188波学杂志第20卷.information of resultant polymer. With the powerful aid of NMR technique , the microstructure of re-sultant polymer can be analyzed and the possible olefin polymerization mechanism could be suggest-In this paper , we will introduce recent results of ESR and NMR studies in polymer science andcatalysis technology field obtained in our research group.1APPLICATION OF ESR TO INVESTIGATION OF METAL-LOCENE CATALYST AND POLYOL .EFIN1.1 ESR Studies of vanadocene cocatalyst systems for ethylene polymerizationTo obtain the information of the coordination structure of the active species during olefin poly-merization , Wang 10] et al. used Cp2VCl2-MA0( Cp'-CsHs , MAO = methylalumoxane ) , Cp2VCl2-AlEt3 , Cp2VCl2-Al2 EtzC3 as catalytic systems for ethylene polymerization. The results indicated thatthe Cp2 VCl2-MAO and Cpn VCl2- AlEt oystems were almost inactive for ethylene polymerization andthe Cp2 VCl2-Al2EtsCl3 system had activity. The ESR spectra of Cp2 VCl2-Al2Et;Cl3 systems wereSmTmTtr 6- TwWhmn n，0m-,--WWWmmsSmT-wWwmn上15-WWWmm 1216- wWWwmm 1317- wWWWwn 14Fig.1 ESR spectra of Cpz VCl-AlEtgCls systemsrm temperature ; sam-中国煤化工ples 16 and 17 were measured at liquid nitrogen teTYHCNMHGshown in Figure 1 and its ESR parameters were summarized in Table 1. It was found that at a low Al:V ratio ,such as in entry 5( Table 1 ), there were two paramagnetic species with g'= 1.981 andwith g2=1.988 and A2≈7.1 mT ,respectively , arising from small Cp2 VCl2 solid particles and sol-vated Cp2VCl2. With increasing Al , from V/Al=1:15 to V/Al= 1:3 000 ,a new signal , with g3第2期WANG Wen-qin et al : Aplication of ESR and NMR to Investigation of mllocene .189≈1.983 and A3~4.16 mT , appeared. It was reasonable to assume the new signal arising fromspecies 3' and species 3"as shown in Figure 211 1. Because of their similar coordinating structures ,itwas impossible to distinguish the ESR parameters of species 3' from species 3”. However , these re-sults indicated that there was an equilibrium as shown in Figure 2.Table 1 ESR Parameters of Cp2VCl2/ Al2Et;C; SystemSample No.V/AIA( mT)gAX mT)5( Cp2VCl2/ AlElgCl3 )1:0.51.811.9887. 166( Gp2VCl2/Al2Et,C3) 1:7一1.9907.06X Cp2VCl2/ ALEBCI3)1:15-1.9847.171.9824.148( Cp2 VCl2/ Al2ELsCl3 )1:301.9867.081.9814.169( Cp2VCl2/ Al2Et,Cl3 )1:601.9837.074.2010( Cp2VCl2/ALEsCk) 1:861.9857.02.4.181I( Cp2VC2/Al2EsCz) 1:4277.051X Cp2VC2/ALEgC3) 1:30007.094.1713( Cp2VCl2/A2EgCl )1:300014( Cp2VCl2/Al2Ey,Clz )1.9877.104.13a : measured after 10 mins , b : measured after 20 mins ,c : measured after 30minsWith reaction time increasing from 10 mins( entry 12 ) to 30 mins( entry 14 )at V/AI=3 000 ,their ESR spectra were identical , showing that the coordination reaction in Figure 2 was fast and sta-ble. However ,a transition( as shown in Figure 3 ) from CICp2 VCIEtAlE( Cl ) to CICp2 VCl2AlC2could be observed after 2 weeks , and CICp2i VCl2AIC2 was inactive for olefin polymerizatiof12]. Af-ter introducing ethylene , the ESR spectrum changed , as shown in Figure 1( 15 ) , which revealed apossible procedure for ethylene coordinating to vanadium. When the samples were frozen at liquidnitrogen temperature , the spectra of samples in Figure 1( 14 ) and Figure 1( 15 ) changed to Figure 1( 16) and Figure 1( 17), respectively...1../C1AIT3'~CIAl2Et:Cl~AlEtCl;-C1中国煤化工3”MYHCNMH GElFig.2 Plausible reaction between Cp2 VC2 and Al2EgCl3190波学杂志第20卷./CIC1-AI~CICIm.-CI十CI-iAI、C1CICI一AlKEtFig.3 Transition from CICp2VCIEtAICIE(C Cl ) to CICr VCl2AIC2According to ESR information , a plausible mechanism of ethylene polymerization catalyzed byCp2 VCl2-Al2Et3cl3 systems can be suggested as shown in Figure 4. The mechanism indicated thatthe alkylation and the reduction ability of the cocatalyst were important factors for the formation of apolymerization active center./CAlCl1E1IAl:CHgEtz一ECI(Et)r CH2CH2 ... . SHCH:CHgCH:Fig.4 A Plauible Mechanism of Ethylene Polymerization Catalyzed by CprVCl2/ AbEyCl3 Systen1.2 ESR Studies of the supported catalyst systemsRecently some interests are focused on development of catalysts with complex support. For ex-ample , Zeolite/ MgCl2 is usually used as the support to prepare the supported Ziegler-Natta( Z-N )catalysts. However ，the composition and the microenvironmental information of the co-support arevery important for obtaining a catalyst with high polymerization activity. Wang 13 'et al. developed anew method using VO2+ as a spin probe to ob中国煤化工omation on supports andused MgCl2/ NaY complex support to supportC N M H Grimental ESR spectra andsimulated ESR spectra were shown in Figure 5. The results indicated that the dispersing ability in-creased in the order of 5A zeolite < 13X zeolite≈ NaY zeolite . This order was consistent with poly-merization activity obtained by complex supported catalysts selecting 5A zeolite , 13X zeolite , or NaYzeolite as second component of the support respectively.第2期WANG Wen-qin et al : Aplication of ESR and NMR to Investigation of mllocene .191(al10 mT(b)A5AS'35~B5'C5C5'Fig.5 ( a) experimental and( b ) simulated ESR Spectra of sample AS( 5A zeolite ) ,BS( 13X zeolite )and C5( NaY zeolite )As known , internal donor and extermal donor added in the supported Ziegler-Natta catalyst canaffect the activity and stereospecificity virtually. Wang14]et al. have used ESR to study the influ-ence of extermal donof di-n-butyl phthalate ) and intemal donof diphenyl dimethoxyl silane ) on co-ordination of active sites . Plausible structure models and mechanisms on the interaction of Ti withMgCl2 , DNBP and DPDMS were proposed.Nat/ 0D、1)) 0ro0oo、NH4+/ 0.0(2(o'/°\**0\(3)°HOHO、(4o’I AI2CI.EI，Si-0-AICI01中国煤化工a). |Tric1MHCNMH GC;1,sCI.S1- -0-A一C1 Si-0-Ai一C1Fig.6 Possible main reactions in the preparation of catalyst192波学杂志第20卷.Usually , the supported Ziegler- Natta catalyst system without MgCl2 has low activity for propy-lene polymerization. However , Wang"5et al. have used Y Zeolite as support only and prepared .TiCl/Al2Et,Clz/ Y Zeolite catalyst system with high activity for copolymerization of ethylene andpropylene. The possible main reactions in the preparation of catalysts were shown in Figure 6. Thepolymerization result showed that the catalyst system supported by Y Zeolite had high catalytic ef-ciency( 10.2 kgP/gTi h). The ESR spectra of the system were shown in Figure 7. It was foundwhen the content of Ti was increased( OH: Al:Ti= 1:1:0.01 ), there was one rotating catalyticspecies in solid phase( Fig. 7b ) and no signal appeared in liquid phase( Fig.7a).a. Liquid phascb. Liquid phase+solid phaseOH:AI:Ti=1:1:0.01Fig.7 ESR spectra of TC4/ Al2EtClz/HY catalytic system1.3 ESR studies of segment motion of polyolefinDrag reduction agents are very important for decreasing the crude oil resistance when the oilwas transferred in the tube. Though the polyolefin are widely used as drag reduction agents in oiltransportation , at present , the drag reduction mechanism of polyolefin added in the crude oil is notvery clear. Usually the drag reduction eficiency is related to its segment motion. Wangl6J et al.used 2 2 6 6-tetrmethylpoperidone as a spin probe to monitor the segment motion of drag reductionagents of crude oil. The typical ESR spectra showing the motion of probe molecules in the amor-phous region of polymer were recorded at different temperatures as shown in Figure 8 and the valvesof Ts mTr were calculated to correlate to drag reduction efficiency. It was discovered that the lower theTs mT , the higher the drag reduction efficiency .1.4 ESR Studies of Poly( ferrocenylsilanes )Since Manners 17 J and coworkers synthesized_ Poly( ferrocenvsilanes ) with high molecularweight by ring-opening method firstly in 1992中国煤化工lymers containing transi-tion metal in their skeletons and having mfYHC N M H Gting growing atention.Wang 181 et al. have synthesized high molecular weight poly( ferrocenylsilanes ) and used ESR tech-nique to study the formation of charge transfer complexe( CTC ) between poly( ferrocenylsilanes ) andtetracyanoethylene( TCNE ) and the segment motion of resultant polymers. The preparation of poly( ferrocenylsilanes ) was shown in Figure 9.第2期WANG Wen-qin et al : Aplicaion of ESR and NMR to Investigation of mllocene .193-169.9"(-121025 'C-100 *C45.2"C-72 °C-49.4C65'C-40“C85"C-35°(105*C-30“心-25'C125* C-14.8 (145*C-0.04*CFig.8 The ESR spectra of the copolymer of butylene-octene at the dffrent temperaturesR’.rRRBuLiR2SiCl2_heatFMonomer一R’Fig.9 The preparation of pols( frernysilanes )5 mT5mThHHHHI-W-一Wr-HMHHK一W-- VMn2Fig.10 ESR spectra of frrocene/TCNE. (a) Empty tub中国煤化工r-pobed reulant plymes(a)( b)TCNE( e ferrocene( d ) frrocene/TCNEYHC N M H Gnmperaturle ,(b)Sample A mea-(d) Sample B measured at 100 K , sample A : Mw=8.5x10+ ,sample B: Mw= 10.1x 10+In the Fig. 10 d) , there was an ESR signal with g≈2 , which confirmed the formation of com-194波学杂志第20卷.plex between pol( ferrocenylsilanes ) and TCNE , which is important for preparation of polymer mag-netic materials. Usually , the segmental motion of a polymer is an important property for polymerprocessing. Information on the segment motion of polymer can be obtained indirectly by observingthe ESR signals of spin-probed polymers .ESR spectra of spin-probed resultant polymers with different molecular weights were shown inFigure 11 , which indicated that the polymer chain with lower molecular weight ( sample A ) wasmore flexible than that with the higher molecular weight( sample B )ESR spectra of spin-probed resultant polymers at different temperatures were shown in Figure12 , it was obvious that , with decreasing temperature from 290 K to 100 K , the segment motion ofresultant polymer was frozen gradually. It also was found that the segment motion of resultant poly-mer with higher molecular weight was frozen earlier than that with low molecular weight.5 mlabd。eN\Fig.12 ESR spectra of spin-probed resultant polymers recorded at( a)290 K ,(b)280K ,(c)270K ,( d)260K ,(e)250K ,(f)240K ,(g)100 K .1.5 ESR Studies of Hydrated Cu 'ZeoliteAs known , Cu/ zeolite is a excellent catalyst due to its high catalytic activity in NO decomposi-tiorf 19 20]. Most attention has focused on the catalytic activity at ideal condition. However , water ispresent in exhausted gas under real condition. Wang 21 22 J has studied hydrated Cu/ zeolite to obtainthe coordination information of hydrated Cu in zeolite by ERS technique. The ESR investigation ofhydrated Cu/ ZSM-5 , Cu/ Mordenit , Cu/Erion中国煤化工:d that multiple hydratedCu species with different coordination environm:YHC N M H Gthe size of zeolite cavitieswas important for accommodating Cu species and even for resulting Cu/ zeolite NO decompositioncatalyst.2 APPLICATION OF NMR IN INVESTIGATION OF METAL -L .OCENE CATALYST AND POL YOL .EFIN第2期WANG Wen-qin et al : Aplication of ESR and NMR to Investigation of mllocene .1952.1 NMR studies of the microstructure of the polyolefinBranched polyethylen( PE ) is a remarkable polyolefin material usually obtained by copolymer-ization of ethane with an a-olefin. Wang 231 et al. found that branched polyethylene could be pre-pared using [ Me2C( Cp X Ind )]ZrCl2( Ind = indenyl ) metallocene catalyst using ethane only asmonomer. I3C NMR spectra of the resultant polymer were shown in Figure 13. C and C2 signalswere detected in the BC NMR spectra of polyethylene , which confirmed that the resultant polymerwas branched polyethylene .CHCa Cp Cy~ CH2CH2CH2CH2CHCH2CH2CH2CH2 mo CH2CH2CH3CH2 C2CH3 Cq(CH2).ACHCy|cC，B4535302520Fig. 13 The 13C NMR spectra of the resultant polyethylene. Polymerization conditions:p=70C ,[ Zr]=3x 10-5 mol/L A :Al/Zr=2000 , B :Al/Zr=3 000 ,C :Al/Zr=5 0002.2 NMR studies of the mechanism of the中国煤化工As known ,the sequence distribution of et:YHC N M H Gdirectly afects the physi-cal-mechanical properties of copolymers. BC NMR is an useful tool to study the sequence distribu-tion of ethylene-propylene copolymert[2425]. Wang'used VOCl3/MgCl2/NaY/Al2EtCl3 complexsupport catalyst for preparing the copolymer of ethylene and propylene. A typical '3C NMR spectrumof the resultant copolymer was shown in Figure 14 .196波学杂志第20卷.24xB83吕∞志21-41022&R 2019Fig. 14 BC NMR spectrum of resutant ethylene-propylene copolymerBy considering inverted propylene units , utilizing all spectrum data and dividing them into sixgroups ,a new computation method based on the first-order Markov terpolymerization model was de-veloped. The six groups of peaks are :(1)S&(2)Say+Sa+(3)Sq+ Ty+ + T+ Ts+g+(4)Tpy+ +Sr+ Sy8+ + Ss*g+(5 )Tg+Sgxy+ Sps+ ,(6)Sβ+ Ppy* + P+ Py~y+The following equations can be obtained :fi=kP31P161-P21- P23)+K( PI3P23+ P13P21+ P12P1311- P31)-A|fz=2 kP3lP2P21+ kP3(1- P2页Pr3P23+ PI3P21+ Pr2P23)]- A2fs=kP3s( P21+ P23I(1-Pn-PI3)PI6 P23+ P21)+ PI3P31]+ kPr2P3[ P2( P31+2)+ P21P16 P21+ P2)]+ K( P3P23+ PI3P21+ PI2P22I P31PId P21+ P23+2)]-A3f4=kPs{ P21+ P23) P2+ P3-Pn2P21- P2P23- P3P31 +2)+ kP3]Pr6( - P23P23-P21P21-2P21P23- P31P23-2P21+ P23+ P21P2)+ k( P3P23+ P3P21+ Pr2P23 )( P31P13+2Pn2P31-2P31- P3|P3|)]- A4fs=kP3|PI[(1- P21- P23尸+2P2(1- P2)]+( Pi3P23+ PI3P21+ Pl2P23I( 1-P31)+2P3(1- Pr2- PI3)]-Asfr=P3IP$ P21P12+1)+k( Pi3P23+ PI3P21+ Pr2P23 P3[P13+ 1)- A6(S，T, and P refer , respectively , to the methylene , methine , and methyl carbons ; theGreek subscripts refer to the next nearest methvl substitution ; P:: and A refer to conditional proba-bility and spectrum data , respectively. )中国煤化工Through solving these equations by theMHCNMH Greconditional probabilitycan be obtained and from which the reactivity ration and sequence distribution can be calculated.The calculated values were very consistent with the observed values , which showed that this methodwas applicable to copolymer both having and not having inverted propylene in the chain , and not on-ly could be utilized for calculating the area of peaks and kinetic parameters r1，r2 but also could第2期WANG Wen-qin et al : Aplicaion of ESR and NMR to Investigation of mllocene .197avoid the difculies of separating peaks and the errors caused by such separaing peaks.Wang26]et al. had prepared [( CH3 )C( ηCsH4 )( η-CgH6 )]zrCl2 and [ CH( CH2 )C .( η-CsH4 X η-CaH6 ) ]ZrCl2 mlallocene catalysts , which were employed in a study of ethylene poly-merization. The resultant polyethylene was characterized by IBC NMR. The signals δ 11.1 and 26.6 , arising from C and C2 , respectively , were detected. The result revealed that the resultantpolyethylene was a short chain-branched polyethylene. The possible mechanism of short chainbranch formation in ethylene polymerization was shown in Figure 15.HPH+H2C=CH2一→(2>YC<小H2C-CH2( poly merizationHH(>MH]H2C---CH2;H(>CH2 NHH2Ctransferbranching,H[(2>x一HCH3,CH2CH;Fig. 15 Possible mechanism of formation of short chain branches during ethylene homopolymerizationCONCL USIONESR and NMR play very important roles in offering the microstructure information of polymerand catalyst. Using ESR technology , we can obtain in detail the information of segment motion ofresultant polymer and the information of coordination of the catalytic active center to elicit the possi-ble polymerization mechanism. By NMR technology , we can get the microstructure information of re-sultant polymer , which is important for improving properties of polymer.中国煤化工MYHCNMHG198波学杂志第20卷.Acknowledgement Financial support from the Natural Science Foundation of China is gratefullyacknowledged. In addition ,we especially thanked Professor CHEN Shi-ming of Fudan University forESR measurement.References :[1] ZhangP Y , Wang L，Jiang s. Sudy on Kinetics of Ethylene Polymerization Using Cp2ZrCl/ Boron modifed MAO CatalyticSysten[J]. J Polym Mater ,2001 ,18 329 - 332.[2] ZhangP Y , Wang L , Feng L F. Ethylene Polymerization Using Modifed Superfine SiO2 Supported Metallocene Catalys[J]. JPolym Mater , 2002 ,19 :121- 126.[3] Marinsky C , Minot C , Ricart J M. A Theoretical invstigationn of the binding of TiCln to MgCl[J]. Surf Sci ,2001 A490 237- 250.[4] Yang X M , Stemn C L, Marks T J" Cation like" homogeneous Olefin Polymerizaion Catalysts Based upon Zironocene Alkylsand Tid pentafluorophenyl )orand[J] J Am Chem Soe , 1991 113 : 3623 - 3625.[5] KimS H , Somorjai G A. Model Ziegler-Natta Polymerization Catalysts Fabricated by Reactions of Mg Metal and TCL : FilmStructure , Composition , and Deposition Kinetie[ J]. J Phys Chem B 2000 ,104 5519 - 5526.[ 6] Bueschges U , Chien J C w. Meallocene-Methylaluminoxane Catalysts for olefin Polymerizations. II . Reduction of f-cyclopen-tadienyl Tichlorides of Titanium and Zirconiun[ J]. J Polym Sci : Part A : Polym Chem , 1989 27 :1525 - 1538.[7] XuJT ,ZhaoJ , Fan ZQ，et al. ESR study on Si-Supported half- tanocene catalyst for Syndiospecifc Polymerization ofStyren[ J]. Macronol Rapid Comm , 1997 18 875 - 882.[8] Wang L, FengLX ,LinJF ,et al. Copolymrzation of Ethylene and Propylene over a supported Zieglar- Natta Catalyst System[J] J Polym Mater , 1993 ,10 61 - 65.[9] Wang L, Feng L X ,Yang s L. SiO-Supported High Efective Ziegler- Natta Catalysts for Compolymerization of Propylene andEthylend J]. Ch Acta Chimica Sinica ,1995 53 310 - 312.[10] Wang L , Zhang,P Y ,Feng LX，e al. ESR Sudies on Vanadocene/Cocalalyst Systems for Ethylene Polymerizatior[J]. JAppl Polym Sci 2001 79 1188 - 1194.[11] WangQ , WengJ H , Xu L, et al. Multiple active site model of ethylene polymerization with Cp2ZrCI-alminoxanes CatalyticSysten[ J]. Polymer , 1999 A0 :1863 - 1870.[12] Evans,A G，EvansJ C , Moon,E H. Electron Spin Resonance Studies Ziegler-type Catalysts. Part I 。Characterisation ofVanadium- Aluminium Complex obtained on mixing Dichlorobi( n-cyclopentadienyl ) Vanadium With Ethylaluminium Dichloride[J] J Chem Soc , Dalton Trans , 1974 2390 - 2395.[13] WangL, FengLX , YangS L. Studies on VOC2/ MgCl2/ NaY/ AlEtCl3 Complex Support Catalysts for the Copolymerizationof Ethylene and Propylen[J]. J Appl Polym Sci , 1994 ,54 :1403 - 1408 .[14] Wang L,FengLX ,XuJT ,et al. Study on Highly Active Ziegler-Natta Catalysts for Polymerization of olefmn[ J]. ChineseJ Polym Sci ,1995 ,I3 41-50.[15] WangL, FengLX ,XuJT ,et al. Sudies on TCL/ Al2EgC3/ Y Zeolite High Efetive Catalytic System for Copolymeriza-tion of Ethylene and propylend[ J]. ChemJ Chinese Unin 1992 14 501- 502[16] WangL,FengLX，Mao,Q G ,et al . The study on中国煤化工。gents of Crude oil using2 2 6 6-tetramethypipeidones as Spin Probe[ J]. Chem J Chir:MYHCNMHG[17] Foucher ,D A , Tang B Z , Manners I. Ringopening polymerization of strained , Ring-Tilted Ferrocenophanes: A Route toHigh Molecular Weight Pol( frocenylsilanesIJ] J Am Chen Soe , 1992 ,114 6246 - 6248.[18] WangL, WangXJ,Pan J,et al. Study on ESR Spectra of Poly ( ferocenoldimelylsilane )TCNE and Spin Probed Poly( rrcenydimethysilaneIJ] J Appl Polym Sci ,( in press)[ 19] Iwamoto M , Yahiro H , Tanda K , et al . Renoval of Nitrogen Monoxide through a novel catalytic process. I . Decomposition第2期WANG Wen-qin et al : Aplication of ESR and NMR to Investigation of mllocene .199on Exessively copper ion Exchanged ZSN-5 Zeoite[J]. J Phys Chem , 1991 95 3727- 3730.[20] Wichterlova B , Dedecek J , Vondrova A. ldenification of Cu Sites in ZSN-5 Active in NO Deompositior[ J] J Phys Chem ,1995 ,99 :1065- 1067.[21 ] Wang L. ESR Studies on Hydrated Cu Zeolid[ J] J Zhejiang Univ ( Natural Science ) ,1997 ,( supplenent )71- 75.[22] Wang L. ESR Studies on Hydrated Cu/ Zeolit[J] J Zhejiang Univ ( Natural Science) ,1997 ,( supplement ) 76- 80.[23] Yuan Y L, Wang L, Feng L X. Preparation of branched polyethene using a soluble zirconocene catalys[ J]. Polymer Int ，2000 A9 :1289- 1292.[24 ] Randall J C. Methylene Sequence Distributions and Number Avenge Sequence Lengths in Ethylene-Propylene CopolymerC J ].Macronolecules. , 1978 ,11 33- 36.[25] Cheng H N. BC NMR Analysis of Ethylene Propylene Ruber[ J]. Macromolecules , 1984 ,17 :1950- 1955.[26] Wang L, Yuan Y L, Feng L X ,et al. Short chain-branched polyehylene produced by[( CH3 )a η←-CsH I η-CGH )LrC2and[ CH( CH2 )a η-GH Y η-CGH )ZrCl2 mallocene catalys[JJ Eur PolymJ ,2000 , 36851- 855.ESR和NMR在茂金属催化剂和聚烯烃研究中的应用王文钦,王立”,王剑峰,马振利(浙江大学高分子科学与工程学系,浙江杭州310027 )摘要:随着高分子科学和催化技 术的发展了解聚合物和催化剂的微结构信息尤为重要.主要介绍了ESR和NMR在茂金属催化剂和聚烯烃领域中的最新应用研究成果表明ESR和NMR是研究聚合物和催化剂微观信息的有效工具.关键词:ESR;NMR;茂金属;聚烯烃;微结构信息中国煤化工MYHCNMHG" 通讯联系人