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1.
Ying‐Yun Long Wei‐Ping Ye XIN‐CUI SHI Yue‐Sheng Li 《Journal of polymer science. Part A, Polymer chemistry》2009,47(22):6072-6082
Three heteroligated (salicylaldiminato)(β‐enaminoketonato)titanium complexes [3‐But‐2‐OC6H3CH?N(C6F5)][(p‐XC6H4)N?C(But)CHC(CF3)O]TiCl2 ( 3a : X = F, 3b : X = Cl, 3c : X = Br) were synthesized and investigated as the catalysts for ethylene polymerization and ethylene/norbornene copolymerization. In the presence of modified methylaluminoxane as a cocatalyst, these unsymmetric catalysts exhibited high activities toward ethylene polymerization, similar to their parallel parent catalysts. Furthermore, they also displayed favorable ability to efficiently incorporate norbornene into the polymer chains and produce high molecular weight copolymers under the mild conditions, though the copolymerization of ethylene with norbornene leads to relatively lower activities. The sterically open structure of the β‐enaminoketonato ligand is responsible for the high norbornene incorporation. The norbornene concentration in the polymerization medium had a profound influence on the molecular weight distribution of the resulting copolymer. When the norbornene concentration in the feed is higher than 0.4 mol/L, the heteroligated catalysts mediated the living copolymerization of ethylene with norbornene to form narrow molecular weight distribution copolymers (Mw/Mn < 1.20), which suggested that chain termination or transfer reaction could be efficiently suppressed via the addition of norbornene into the reaction medium. Polymer yields, catalytic activity, molecular weight, and norbornene incorporation can be controlled within a wide range by the variation of the reaction parameters such as comonomer content in the feed, reaction time, and temperature. ©2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 6072–6082, 2009 相似文献
2.
Quasi‐living copolymerization of ethylene with 1‐hexene by heteroligated (salicylaldiminato β‐enaminoketonato) titanium complexes
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Ying‐Yun Long Yong‐Xia Wang Bai‐Xiang Li Yan‐Guo Li Yue‐Sheng Li 《Journal of polymer science. Part A, Polymer chemistry》2017,55(17):2787-2797
A series of heteroligated (salicylaldiminato)(β‐enaminoketonato)titanium complexes [3‐But‐2‐OC6H3CH = N(C6F5)] [PhN = C(R1)CHC(R2)O]TiCl2 [ 3a : R1 = CF3, R2 = tBu; 3b : R1 = Me, R2 = CF3; 3c : R1 = CF3, R2 = Ph; 3d : R1 = CF3, R2 = C6H4Ph(p ); 3e : R1 = CF3, R2 = C6H4Ph(o ); 3f : R = CF3, R2 = C6H4Cl(p ); 3g : R1 = CF3; R2 = C6H3Cl2(2,5); 3h : R1 = CF3, R2 = C6H4Me(p )] were investigated as catalysts for ethylene (co)polymerization. In the presence of modified methylaluminoxane as a cocatalyst, these complexes showed activities about 50%–1000% and 10%–100% higher than their corresponding bis(β‐enaminoketonato) titanium complexes for ethylene homo‐ and ethylene/1‐hexene copolymerization, respectively. They produced high or moderate molecular weight copolymers with 1‐hexene incorporations about 10%–200% higher than their homoligated counterpart pentafluorinated FI‐Ti complex. Among them, complex 3b displayed the highest activity [2.06 × 106 g/molTi?h], affording copolymers with the highest 1‐hexene incorporations of 34.8 mol% under mild conditions. Moreover, catalyst 3h with electron‐donating group not only exhibited much higher 1‐hexene incorporations (9.0 mol% vs. 3.2 mol%) than pentafluorinated FI‐Ti complex but also generated copolymers with similar narrow molecular weight distributions (M w/M n = 1.20–1.26). When the 1‐hexene concentration in the feed was about 2.0 mol/L and the hexene incorporation of resultant polymer was about 9.0 mol%, a quasi‐living copolymerization behavior could be achieved. 1H and 13C NMR spectroscopic analysis of their resulting copolymers demonstrated the possible copolymerization mechanism, which was related with the chain initiation, monomer insertion style, chain transfer and termination during the polymerization process. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55 , 2787–2797 相似文献
3.
Guangrong Tang Yue‐Jian Lin Guo‐Xin Jin 《Journal of polymer science. Part A, Polymer chemistry》2008,46(2):489-500
A series of new indanimine ligands [ArN?CC2H3(CH3)C6H2(R)OH] (Ar = Ph, R = Me ( 1 ), R = H ( 2 ), and R = Cl ( 3 ); Ar = 2,6‐i‐Pr2C6H3, R = Me ( 4 ), R = H ( 5 ), and R = Cl ( 6 )) were synthesized and characterized. Reaction of indanimines with Ni(OAc)2·4H2O results in the formation of the trinuclear hexa(indaniminato)tri (nickel(II)) complexes Ni3[ArN = CC2H3(CH3)C6H2(R)O]6 (Ar = Ph, R = Me ( 7 ), R = H ( 8 ), and R = Cl ( 9 )) and the mononuclear bis(indaniminato)nickel (II) complexes Ni[ArN?CC2H3(CH3)C6H2(R)O]2 (Ar = 2,6‐i‐Pr2C6H3, R = Me ( 10 ), R = H ( 11 ), and R = Cl ( 12 )). All nickel complexes were characterized by their IR, NMR spectra, and elemental analyses. In addition, X‐ray structure analyses were performed for complexes 7 , 10 , 11 , and 12 . After being activated with methylaluminoxane (MAO), these nickel(II) complexes can polymerize norbornene to produce addition‐type polynorbornene (PNB) with high molecular weight Mv (106 g mol?1), highly catalytic activities up to 2.18 × 107 gPNB mol?1 Ni h?1. Catalytic activities and the molecular weight of PNB have been investigated for various reaction conditions. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 489–500, 2008 相似文献
4.
Li‐Ming Tang Tao Hu Li Pan Yue‐Sheng Li 《Journal of polymer science. Part A, Polymer chemistry》2005,43(24):6323-6330
Copolymerizations of ethylene with α‐olefins (i.e., 1‐hexene, 1‐octene, allylbenzene, and 4‐phenyl‐1‐butene) using the bis(β‐enaminoketonato) titanium complexes [(Ph)NC(R2)CHC(R1)O]2TiCl2 ( 1a : R1 = CF3, R2 = CH3; 1b : R1 = Ph, R2 = CF3; and 1c : R1 = t‐Bu, R2 = CF3), activated with modified methylaluminoxane as a cocatalyst, have been investigated. The catalyst activity, comonomer incorporation, and molecular weight, and molecular weight distribution of the polymers produced can be controlled over a wide range by the variation of the catalyst structure, α‐olefin, and reaction parameters such as the comonomer feed concentration. The substituents R1 and R2 of the ligands affect considerably both the catalyst activity and comonomer incorporation. Precatalyst 1a exhibits high catalytic activity and produces high‐molecular‐weight copolymers with high α‐olefin insertion. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 6323–6330, 2005 相似文献
5.
Kohtaro Osakada Yasumasa Takenaka Jun‐Chul Choi Isao Yamaguchi Takakazu Yamamoto 《Journal of polymer science. Part A, Polymer chemistry》2000,38(9):1505-1511
Copolymerization of (4‐hexylphenyl)allene and of (4‐dodecylphenyl)allene with carbon monoxide (1 atm) catalyzed by Rh[η3‐CH(Ar′)C{C(CHAr′)CH2C (CHAr′)CH2CH2CHCHAr′}CH2](PPh3)2 (A; Ar′ = C6H4OMe‐p) gives the corresponding polyketones: I‐[—CO—C(CHAr)—CH2—]n [1: Ar = C6H4C6H13‐p, 2 : Ar = C6H4C12H25‐p; I = CH2C(CHAr′)C(CHAr′)CH2C(CHAr′)CH2CH2CHCHAr′]. Molecular weights of the polyketone prepared from (4‐hexylphenyl)allene and CO are similar to the calculated from the monomer to initiator ratios until the molecular weight reaches to 45,000, indicating the living polymerization. Melting points of the polyketones I‐[—CO—C(CHC6H4R‐p)—CH2—]n (n = ca. 100) increase in the order R = C12H25 < C6H13 < C4H9 < CH3 < H. Block and random copolymerization of phenylallene and (4‐alkylphenyl)allene with carbon monoxide gives the new copoly‐ ketones. The polymerization of a mixture of (4‐methylphenyl)allene and smaller amounts of bis(allenyl)benzene under CO afforded the polyketone with a crosslinked structure. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 1505–1511, 2000 相似文献
6.
α‐keto‐β‐diimine nickel‐catalyzed olefin polymerization: Effect of ortho‐aryl substituents and preparation of stereoblock copolymers
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Anatolij Sokolohorskyj Ondřej Železník Ivana Císařová Johannes Lenz Albena Lederer Jan Merna 《Journal of polymer science. Part A, Polymer chemistry》2017,55(15):2440-2449
A series of α‐keto‐β‐diimine nickel complexes (Ar‐N = C(CH3)‐C(O)‐C(CH3)=N‐Ar)NiBr2; Ar = 2,6‐R‐C6H3‐, R = Me, Et, iPr, and Ar = 2,4,6‐Me3‐C6H3‐) was prepared. All corresponding ligands are unstable even under an inert atmosphere and in a freezer. Stable copper complex intermediates of ligand synthesis and ethyl substituted nickel complex were isolated and characterized by X‐ray. All nickel complexes were used for the polymerization of ethene, propylene, and hex‐1‐ene to investigate their livingness and the extent of chain‐walking. Low‐temperature propene polymerization with less bulky ortho‐substituents was less isospecific than the one with isopropyl derivative. Propene stereoblock copolymers were prepared by iPr derivative combining the polymerization at low temperature to prepare isotactic polypropylene (PP) block and at a higher temperature, supporting chain‐walking, to obtain amorphous regioirregular PP block. Alternatively, a copolymerization of propene with ethene was used for the preparation of amorphous block. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55, 2440–2449 相似文献
7.
Alan R. Cabrera Yanika Schneider Mauricio Valderrama Griselda B. Galland Rene S. Rojas 《Journal of polymer science. Part A, Polymer chemistry》2011,49(7):1535-1542
[3‐Cyano‐2‐(2,6‐diisopropylphenyl)aminopent‐2‐en‐4‐(phenylimine)tris (pentafluorophenyl)borate](η5‐C5H5)ZrCl2, [(B(C6F5)3‐ NC‐nacnac)CpZrCl2], precatalyst ( 2 ) can be treated with low concentrations of methylaluminoxane (MAO) to generate active sites capable of copolymerizing ethylene with 1‐octadecene or norbornene under mild conditions. A series of poly(ethylene‐co‐octadecene) and poly(ethylene‐co‐norbornene) copolymers were prepared, and their properties were characterized by NMR, differential scanning calorimetry, and mechanical analysis. The results show that this system produced poly(ethylene‐co‐octadecene) copolymers with a branching content of about 8 mol %. However, upon increasing the comonomer concentration, a drastic reduction in the Mn of the product is observed concomitant with an increase in comonomer incorporation. This leads to a gradual decrease in Young's modulus and stress at break, indicating an increase in the “softness” of the copolymer. In the case of copolymerizations of ethylene and norbornene, the catalytic system ( 2 /MAO) shows a substantial decrease in reactivity in the presence of norbornene and generates copolymer chains in which 5–10 mol % norbornene is in blocks. We also observe that ethylene norbornene copolymers exhibit a high degree of alternating insertions (close to 50%), as determined by NMR spectroscopy. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011 相似文献
8.
Dong‐Po Song Hong‐Liang Mu Xin‐Cui Shi Yan‐Guo Li Yue‐Sheng Li 《Journal of polymer science. Part A, Polymer chemistry》2012,50(3):562-570
The facile and efficient functionalization of polynorbornene has been achieved through direct copolymerization of norbornene (NB) with 5‐norbornene‐2‐yl acetate (NBA) or 5‐norbornene‐2‐methanol (NBM) using a series of β‐ketiminato Ni(II)‐Me pyridine complexes 1–4 (Scheme 2 ) in the presence of B(C6F5)3. Remarkably, the monomer conversion could reach up to about 96% in 10 min in the NB/NBA copolymerization. The copolymers with wide NBA contents (3.3–38.4 mol %) were obtained by variation of reaction conditions. These copolymers have high molecular weights (MWs) (Mn = 41.8–144 kg/mol) and narrow MW distributions (Mw/Mn = 1.80–2.27). In the absence of alkyl aluminum compounds, a monomer conversion of 81% was observed in the NB/NBM copolymerization, and copolymers with NBM content in the range of 11.2–21.8 mol % were obtained by variation of reaction conditions. In addition, Ni(II)‐Me pyridine complexes 2 was very active at a low B/Ni molar ratio of 6, while bis‐ligand complex 6 bearing the same ligand just showed moderate efficiency at a high B/Ni molar ratio of 20. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011 相似文献
9.
Kaiti Wang Yiwang Chen Xiaohui He Yueman Liu Weihua Zhou 《Journal of polymer science. Part A, Polymer chemistry》2011,49(15):3304-3313
Two complexes Mt{C10H8(O)C[N(C6H5)]CH3}2 [Mt = Ni(II); Mt = Pd(II)] were synthesized, and the solid‐state structures of the complexes have been determined by single‐crystal X‐ray diffractions. Homopolymerization of norbornene (NB) and copolymerization of NB and 5‐norbornene‐2‐yl acetate (NB‐OCOCH3) were carried out in toluene with both the two complexes mentioned above in combination with B(C6F5)3. Both the catalytic systems exhibited high activity toward the homopolymerization of NB (as high as 2.7 × 105 gpolymer/molNi h, for Ni(II)/B(C6F5)3 and 2.1 × 105 gpolymer/molPd h for Pd(II)/B(C6F5)3, respectively.). Although the Pd(II)/B(C6F5)3 shows very lower activity toward the copolymerization of NB with NB‐OCOCH3, Ni(II)/B(C6F5)3 shows a high activity and produces the addition‐type copolymer with relatively high molecular weights (MWs; 1.80–2.79 × 105 g/mol) as well as narrow MW distribution (1.89–2.30). The NB‐OCOCH3 content in the copolymers can be controlled up to 5.8–12.0% by varying the comonomer feed ratios from 10 to 50%. The copolymers exhibited high transparency, high glass transition temperature (Tg > 263.9 °C), better solubility, and mechanical properties compared with the homopolymer of NB. The reactivity ratios of the two monomers were determined to be rNB‐OCOMe = 0.08, rNB = 7.94 for Ni(II)/B(C6F5)3 system, and rNB‐OCOMe = 0.07, rNB = 6.49, for Pd(II)/B(C6F5)3 system by the Kelen‐Tüdõs method. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011 相似文献
10.
Wannida Apisuk Naohiro Suzuki Hyun Joon Kim Dong Hyun Kim Boonyarach Kitiyanan Kotohiro Nomura 《Journal of polymer science. Part A, Polymer chemistry》2013,51(12):2565-2574
Aryloxo‐modified half‐titanocenes, Cp′TiCl2(O‐2,6‐iPr2C6H3) [Cp′ = Cp* ( 1 ), tBuC5H4 ( 2 )], catalyze terpolymerization of ethylene and styrene with α‐olefin (1‐hexene and 1‐decene) efficiently in the presence of cocatalyst, affording high‐molecular‐weight polymers with unimodal distributions (compositions). Efficient comonomer incorporations have been achieved by these catalysts. The content of each comonomer (α‐olefin, styrene, etc.) could be controlled by varying the comonomer concentration charged, and resonances ascribed to styrene and α‐olefin repeated insertion were negligible. The terpolymerization with p‐methylstyrene (p‐MS) in place of styrene also proceeded in the presence of [PhN(H)Me2][B(C6F5)4] and AliBu3 cocatalyst, and p‐MS was incorporated in an efficient matter, affording high‐molecular‐weight polymers with uniform molecular weight distributions. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013, 51, 2565–2574 相似文献
11.
Yann Sarazin Gerhard Fink Klaus Hauschild Manfred Bochmann 《Macromolecular rapid communications》2005,26(15):1208-1213
Summary: The metallocenes rac‐C2H4(Ind)2ZrCl2 ( 1 ), rac‐Me2Si(Ind)2ZrCl2 ( 2 ), and rac‐Me2Si(2‐Me‐benz[e]Ind)2ZrCl2 ( 3 ) efficiently copolymerize propene and 5‐vinyl‐2‐norbornene (VNB). 1 and 2 give a high VNB content and high productivities, whereas 3 gives moderate incorporation. Surprisingly, precatalysts 1 and 2 , which have very closely related structures, showed very different reactivities toward VNB, with 1 having a greater affinity for VNB than for propene. The copolymers are quantitatively converted into polyolefins with polar functionalities.
12.
Norbornene polymerizations were carried out using nickel(II) bromide complexes CH{C(R)NAr}2NiBr ( 1 , R = CH3, Ar = 2, 6 ? iPr2C6H3; 2 , R = CH3, Ar = 2, 6‐Me2C6H3; 3 , R = CF3, Ar = 2, 6 ? iPr2C6H3; 4 , R = CF3, Ar = 2, 6‐Me2C6H3) in the presence of methylaluminoxane. Compound 3 is the most active norbornene polymerization catalyst of all the nickel complexes tested. The activity of theses catalysts increases with increases in steric bulk of the substituents on the aryl rings. The electronic nature of the ligand backbone also affects the activity. The resulting polynorbornenes are vinyl type by IR and NMR analyses. Copyright © 2007 John Wiley & Sons, Ltd. 相似文献
13.
Il Gu Jung Junhyeok Seo Young Keun Chung Dong Mok Shin Sung‐Ho Chun Seung Uk Son 《Journal of polymer science. Part A, Polymer chemistry》2007,45(14):3042-3052
An in situ generated cationic allylpalladium complex bearing N‐heterocyclic carbene (NHC) ligands, derived from the reaction of [(η3‐C3H5)Pd(NHC)Cl] with AgX (X = BF4 or SbF6), is an active catalyst for the addition polymerization of norbornene and norbornene derivatives [5‐norbornene‐2‐carboxylic acid methyl ester ( b ) and 5‐norbornene‐2‐carboxylic acid n‐butyl ester ( c )] with an ester group containing a large portion of endo‐isomers. The catalytic activities, polymer yields, molecular weights, and molecular weight distributions of polynorbornenes were investigated under various reaction conditions: the catalytic activity was highly dependent on the counteranion, the reaction solvent, and the reaction temperature. For b , as the portion of an endo‐isomer increased, the activity of 13 (SbF) was much higher than those of 14 and 15 , and for c (exo/endo = 95:5), the maximum turn over number (TON) was observed with 15 (SbF). © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 3042–3052, 2007 相似文献
14.
Ji‐Qian Wu Li Pan San‐Rong Liu Li‐Peng He Yue‐Sheng Li 《Journal of polymer science. Part A, Polymer chemistry》2009,47(14):3573-3582
A series of novel vanadium(III) complexes bearing heteroatom‐containing group‐substituted salicylaldiminato ligands [RN?CH(ArO)]VCl2(THF)2 (Ar = C6H4, R = C3H2NS, 2a ; C7H4NS, 2c ; C7H5N2, 2d ; Ar = C6H2tBu2 (2,4), R = C3H2NS, 2b ) have been synthesized and characterized. Structure of complex 2c was further confirmed by X‐ray crystallographic analysis. The complexes were investigated as the catalysts for ethylene polymerization in the presence of Et2AlCl. Complexes 2a–d exhibited high catalytic activities (up to 22.8 kg polyethylene/mmolV h bar), and affording polymer with unimodal molecular weight distributions at 25–70 °C in the first 5‐min polymerization, whereas produced bimodal molecular weight distribution polymers at 70 °C when polymerization time prolonged to 30 min. The catalyst structure plays an important role in controlling the molecular weight and molecular weight distribution of the resultant polymers produced in 30 min polymerization. In addition, ethylene/hexene copolymerizations with catalysts 2a–d were also explored in the presence of Et2AlCl, which leads to the high molecular weight and unimodal distributions copolymers with high comonomer incorporation. Catalytic activity, comonomer incorporation, and polymer molecular weight can be controlled over a wide range by the variation of catalyst structure and the reaction parameters, such as comonomer feed concentration, polymerization time, and polymerization reaction temperature. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 3573–3582, 2009 相似文献
15.
Carlos L. P. Carone Geraldo L. Crossetti Nara R. S. Basso Álvaro G. O. Moraes João H. Z. dos Santos Rubens Bisatto Griselda B. Galland 《Journal of polymer science. Part A, Polymer chemistry》2007,45(22):5199-5208
The catalyst DADNi(NCS)2 (DAD = (ArN?C(Me)? C(Me)?ArN); Ar = 2,6‐C6H3), activated by methylaluminoxane, was tested in ethylene polymerization at temperatures above 25 °C and variable Al/Ni ratio. The system was shown to be active even at 80 °C and when supported on silica. However, catalyst activity decreased. The catalyst system was also tested in ethylene and 10‐undecen‐1‐ol copolymerization at different ethylene pressures. The best activities were obtained at low polar monomer concentration (0.017 mol/L), using triisopropylaluminum (Al‐i‐Pr3) to protect the polar monomer. The incorporation of the comonomer increased with the increase of polar monomer concentration. According to 13C NMR analyses, all the resulting polyethylenes were highly branched and the polar monomer incorporation decreased as ethylene pressure increased. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 5199–5208, 2007 相似文献
16.
Yukio Imanishi Kotohiro Nomura 《Journal of polymer science. Part A, Polymer chemistry》2000,38(Z1):4613-4626
Olefin polymerizations catalyzed by Cp′TiCl2(O‐2,6‐iPr2C6H3) ( 1 – 5 ; Cp′ = cyclopentadienyl group), RuCl2(ethylene)(pybox) { 7 ; pybox = 2,6‐bis[(4S)‐4‐isopropyl‐2‐oxazolin‐2‐yl]pyridine}, and FeCl2(pybox) ( 8 ) were investigated in the presence of a cocatalyst. The Cp*TiCl2(O‐2,6‐iPr2C6H3) ( 5 )–methylaluminoxane (MAO) catalyst exhibited remarkable catalytic activity for both ethylene and 1‐hexene polymerizations, and the effect of the substituents on the cyclopentadienyl group was an important factor for the catalytic activity. A high level of 1‐hexene incorporation and a lower rE · rH value with 5 than with [Me2Si(C5Me4)(NtBu)]TiCl2 ( 6 ) were obtained, despite the rather wide bond angle of Cp Ti O (120.5°) of 5 compared with the bond angle of Cp Ti N of 6 (107.6°). The 7 –MAO catalyst exhibited moderate catalytic activity for ethylene homopolymerization and ethylene/1‐hexene copolymerization, and the resultant copolymer incorporated 1‐hexene. The 8 –MAO catalyst also exhibited activity for ethylene polymerization, and an attempted ethylene/1‐hexene copolymerization gave linear polyethylene. The efficient polymerization of a norbornene macromonomer bearing a ring‐opened poly(norbornene) substituent was accomplished by ringopening metathesis polymerization with the well‐defined Mo(CHCMe2Ph)(N‐2,6‐iPr2C6H3)[OCMe(CF3)2]2 ( 10 ). The key step for the macromonomer synthesis was the exclusive end‐capping of the ring‐opened poly(norbornene) with p‐Me3SiOC6H4CHO, and the use of 10 was effective for this polymerization proceeding with complete conversion. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 4613–4626, 2000 相似文献
17.
Ji‐Qian Wu Bai‐Xiang Li Sen‐Wang Zhang Yue‐Sheng Li 《Journal of polymer science. Part A, Polymer chemistry》2010,48(14):3062-3072
Bis(β‐enaminoketonato) vanadium(III) complexes ( 2a–c ) [O(R1)C?C(H)xC(R2)?NC6H5]2VCl(THF) and the corresponding vanadium(IV) complexes ( 3a–c ) [O(R1)C?C(H)xC(R2)? NC6H5]2VO (R1 = ? (CH2)4? , R2 = H, x = 0, a ; R1 = ? C6H5, R2 = H, x = 1, b ; R1 = ? C6H5, R2 = ? C6H5, x = 1, c ) have been synthesized from VCl3(THF)3 and VOCl2(THF)2, respectively, by treating with 2.0 equivalent β‐enaminoketonato ligands in tetrahydrofuran. Structures of 2b and 3a–c were further confirmed by X‐ray crystallographic analysis. The complexes were investigated as the catalysts for ethylene polymerization in the presence of Et2AlCl. Complexes 2a–c and 3a–c exhibited high catalytic activities (up to 23.76 kg of PE/mmolV h bar), and afforded polymers with unimodal molecular weight distributions at 70 °C indicating the good thermal stability. The catalytic behaviors were influenced not only by the oxidation state of the catalyst precursors but also by the ligand structures. Complexes 2a–c and 3a–c were also effective catalyst precursors for ethylene/1‐hexene copolymerization. The influence of polymerization parameters such as reaction temperature, Al/V molar ratio and hexene feed concentration on the ethylene/hexene copolymerization behaviors have bee also investigated in detail. In addition, the agents such as AlMe3, AliBu3, MeMgBr, MgCl2, and ZnEt2 were applied to control the molecular weight and molecular weight distribution modal. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 3062–3072, 2010 相似文献
18.
Highly symmetric single nickel catalysts bearing bulky bis(α‐diimine) ligand: Synthesis,characterization, and electron‐effects on copolymerization of norbornene with 1‐alkene at elevated temperarure
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Xiaohui He Yingjiao Deng Zhilong Han Yingping Yang Defu Chen 《Journal of polymer science. Part A, Polymer chemistry》2016,54(21):3495-3505
Three new three‐dimensional geometry bulky α‐diimine ligands ( L ) containing electron‐donating and electron‐withdrawing groups, 9,10‐dihydro‐9,10‐ethanoanthracene‐11,12‐di(Ar)imine (Ar = p‐PhCH3, L1 ; Ar=p‐PhCl, L2 ; Ar=p‐PhCF3, L3 .), and their corresponding single Ni(II) catalysts, NiL2Br2 ( Ni(L1)2Br2 , Ni(L2)2Br2 , and Ni(L3)2Br2 , were synthesized and the molecular structure were determined by X‐ray crystallography. All NiL2Br2 catalysts were tested for norbornene polymerization and copolymerization of norbornene with 1‐alkene after activation with B(C6F5)3. The results that the polymerization catalytic activities for norbornene up to 105 gpolymer/molNi·h even at 140 °C, shown that NiL2Br2 catalysts have high thermal stability. Meanwhile, catalysts with electron‐withdrawing groups could achieve higher reactivity. The obtained poly(NB‐co‐1‐alkene)s were confirmed to be vinyl‐addition copolymers and noncrystalline. All copolymers exhibited high 1‐alkenes insertion ratio, good thermal stability (Td > 375 °C), high molecular weight (up to 105 g/mol), good solubility in common organic solvents and could be processed into films with good transparency in the visible region. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016 , 54, 3495–3505 相似文献
19.
Wannida Apisuk Boonyarach Kitiyanan Hyun Joon Kim Dong Hyun Kim Kotohiro Nomura 《Journal of polymer science. Part A, Polymer chemistry》2013,51(12):2581-2587
An efficient introduction of vinyl group into poly (ethylene‐co‐styrene) or poly(ethylene‐co?1‐hexene) has been achieved by the incorporation of 3,3′‐divinylbiphenyl (DVBP) in terpolymerization of ethylene, styrene, or 1‐hexene with DVBP using aryloxo‐modified half‐titanocenes, Cp′TiCl2(O?2,6‐iPr2C6H3) [Cp′ = Cp*, tBuC5H4, 1,2,4‐Me3C5H2], in the presence of MAO cocatalyst, affording high‐molecular‐weight polymers with unimodal distributions. Efficient comonomer incorporations have been achieved by these catalysts, and the content of each comonomer could be varied by its initial concentration charged. The postpolymerization of styrene was initiated from the vinyl group remained in the side chain by treatment with n‐BuLi. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013, 51, 2581–2587 相似文献
20.
Andrea Ravasio Laura Boggioni Giulia Scalcione Fabio Bertini Daniele Piovani Incoronata Tritto 《Journal of polymer science. Part A, Polymer chemistry》2012,50(18):3867-3874
Complex [Ti(κ2‐N,O‐{2,6‐F2C6H3N?C(Me)C(H) ?C(CF3) O})2Cl2] ( 1 ) was evaluated as catalyst for living copolymerization of ethylene (E) with norbornene (N) upon activation with dried methylaluminoxane (d‐MAO) at temperatures between 25 and 90 °C. Copolymerization performed at different [N]/[E] feed ratios afforded stereoirregular alternating high molar mass P(E‐co‐N) with narrow molar mass distribution. The living nature of E‐co‐N copolymerization by 1 /d‐MAO was demonstrated by kinetics at 50 °C. This catalyst system was used for the synthesis of block copolymers such as polyethylene (PE)‐block‐P(E‐co‐N) with a crystalline PE block and an amorphous P(E‐co‐N) block as well as P(E‐co‐N)1‐block‐P(E‐co‐N)2, having different norbornene contents in the segments and thus having different Tg values. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012 相似文献