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1.
Poly(propylene‐ran‐1,3‐butadiene) was synthesized using isospecific zirconocene catalysts and converted to telechelic isotactic polypropylene by metathesis degradation with ethylene. The copolymers obtained with isospecific C2‐symmetric zirconocene catalysts activated with modified methylaluminoxane (MMAO) had 1,4‐inserted butadiene units ( 1,4‐BD ) and 1,2‐inserted units ( 1,2‐BD ) in the isotactic polypropylene chain. The selectivity of butadiene towards 1,4‐BD incorporation was high up to 95% using rac‐dimethylsilylbis(1‐indenyl)zirconium dichloride (Cat‐A)/MMAO. The molar ratio of propylene to butadiene in the feed regulated the number‐average molecular weight (Mn) and the butadiene contents of the polymer produced. Metathesis degradations of the copolymer with ethylene were conducted with a WCI6/SnMe4/propyl acetate catalyst system. The 1H NMR spectra before and after the degradation indicated that the polymers degraded by ethylene had vinyl groups at both chain ends in high selectivity. The analysis of the chain scission products clarified the chain end structures of the poly(propylene‐ran‐1,3‐butadiene). © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 5731–5740, 2007  相似文献   

2.
Water‐soluble poly(ester‐carbonate) having pendent amino and carboxylic groups on the main‐chain carbon is reported for the first time. This article describes the melt ring‐opening/condensation reaction of trans‐4‐hydroxy‐N‐benzyloxycarbonyl‐L ‐proline (N‐CBz‐Hpr) with 5‐methyl‐5‐benzyloxycarbonyl‐1,3‐dioxan‐2‐one (MBC) at a wide range of molar fractions. The influence of reaction conditions such as catalyst concentration, polymerization time, and temperature on the number average molecular weight (Mn) and molecular weight distribution (Mw/Mn) of the copolymers was investigated. The polymerizations were carried out in bulk at 110 °C with 3 wt % stannous octoate as a catalyst for 16 h. The poly(ester‐carbonate)s obtained were characterized by Fourier transform infrared spectroscopy, 1H NMR, differential scanning calorimetry, and gel permeation chromatography. The copolymers synthesized exhibited moderate molecular weights (Mn = 6000–14,700 g mol?1) with reasonable molecular weight distributions (Mw/Mn = 1.11–2.23). The values of the glass‐transition temperature (Tg) of the copolymers depended on the molar fractions of cyclic carbonate. When the MBC content decreased from 76 to 12 mol %, the Tg increased from 16 to 48 °C. The relationship between the poly(N‐CBz‐Hpr‐co‐MBC) Tg and the compositions was in approximation with the Fox equation. In vitro degradation of these poly(N‐CBz‐Hpr‐co‐MBC)s was evaluated from weight‐loss measurements and the change of Mn and Mw/Mn. Debenzylation of 3 by catalytic hydrogenation led to the corresponding linear poly(ester‐carbonate), 4 , with pendent amino and carboxylic groups. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 2303–2312, 2004  相似文献   

3.
Poly(isosorbide carbonate) (PIC) was synthesized by melt polycondensation of dimethyl carbonate (DMC) and isosorbide using lithium acetylacetonate (LiAcac) as the catalyst. The reaction conditions were optimized to achieve PIC with relatively high number‐average molecular weight (Mn) of 28,800 g/mol and isosorbide conversion of 95.2%. A series of poly(aliphatic diol‐co‐isosorbide carbonate)s (PAICs) were also synthesized by melt polycondensation of DMC with isosorbide and equimolar amounts of aliphatic diols (1,4‐butanediol, 1,5‐pentanediol, 1,6‐hexanediol, and 1,4‐cyclohexane dimethanol) in the presence of LiAcac and the TiO2/SiO2‐based catalyst (TSP‐44). PAICs with Mn values ranging from 18,700 to 34,400 g/mol and polydispersities between 1.64 and 1.69 were obtained. The 13C NMR analysis revealed the random microstructure of PAICs. The differential scanning calorimetry results demonstrated that all the PAICs were amorphous with a unique Tg ranging from 46 to 88 °C. The dynamic analysis results showed that the incorporation of linear or cyclohexane structure changed the dynamic mechanical properties of PIC drastically. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013  相似文献   

4.
A series of new functional poly(ethylene‐co‐vinyl alcohol)‐g‐polystyrene graft copolymers (EVAL‐g‐PS) with controlled molecular weight (Mn = 38,000–94,000 g mol?1) and molecular weight distribution (Mw/Mn = 2.31–3.49) were synthesized via a grafting from methodology. The molecular structure and component of EVAL‐g‐PS graft copolymers were confirmed by the analysis of their 1H NMR spectra and GPC curves. The porous films of such copolymers were fabricated via a static breath‐figure (BF) process. The influencing factors on the morphology of such porous films, such as solvent, temperature, polymer concentration, and molecular weight of polymer were investigated. Ordered porous film and better regularity was fabricated through a static BF process using EVAL‐g‐PS solution in CHCl3. Scanning electron microscopy observation reveals that the EVAL‐g‐PS graft copolymer is an efficient compatibilizer for the blend system of low‐density polyethylene/polystyrene. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016 , 54, 516–524  相似文献   

5.
The organo‐rare‐earth‐metal‐initiated living polymerization of methyl methacrylate (MMA) was first discovered in 1992 with (C5Me5)2LnR (where R is H or Me and Ln is Sm, Yb, Y, or La) as an initiator. These polymerizations provided highly syndiotactic (>96%) poly(methyl methacrylate) (PMMA) with a high number‐average molecular weight (Mn > 1000 × 103) and a very narrow molecular weight distribution [weight‐average molecular weight/number‐average molecular weight (Mw/Mn) < 1.04] quantitatively in a short period. Bridged rare‐earth‐metallocene derivatives were used to perform the block copolymerization of ethylene or 1‐hexene with MMA, methyl acrylate, cyclic carbonate, or ?‐caprolactone in a voluntary ratio. Highly isotactic (97%), monodisperse, high molecular weight (Mn > 500 × 103, Mw/Mn < 1.1) PMMA was first obtained in 1998 with [(Me3Si)3C]2Yb. Stereocomplexes prepared by the mixing of the resulting syndiotactic and isotactic PMMA revealed improved physical properties. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 1955–1959, 2001  相似文献   

6.
Low‐molecular weight oligo(carbonate‐ether) diols are important raw materials for polyurethane formation, which with tunable carbonate unit content (CU) may endow new thermal and mechanical performances to polyurethane. Herein, facile synthesis of oligo(carbonate‐ether) diols with number average molecular weight (Mn) below 2000 g mol?1 and CU tunable between 40% and 75% are realized in high activity by immortal copolymerization of CO2/propylene oxide (PO) using zinc‐cobalt double metal cyanide complex (Zn‐Co‐DMCC) in the presence of sebacic acid (SA). Mn of the oligomer is in good linear relationship to the mole ratio of PO and SA (PO/SA) and hence can be precisely controlled by adjusting PO/SA. Besides, the molecular weight distribution is quite narrow due to the rapid reversible chain transfer in the immortal copolymerization. High pressure and low temperature are favorable for raising CU. In all the reactions, the weight fraction of propylene carbonate (WPC) can even be controlled as low as 2.0 wt %, and the catalytic activity of Zn‐Co‐DMCC is above 1.0 kgg?1 cat. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012  相似文献   

7.
The polymerization of butadiene (Bd) with Co(acac)3 in combination with methylaluminoxane (MAO) was investigated. The polymerization of Bd with Co(acac)3‐MAO catalysts proceeded to give cis‐1,4 polymers (94 – 97%) bearing high molecular weights (40 × 104) with relatively narrow molecular weight distributions (Mw's/Mn's). The molecular weight of the polymers increased linearly with the polymer yield, and the line passed through an original point. The polydispersities of the polymers kept almost constant during reaction time. This indicates that the microstructure and molecular weight of the polymers can be controlled in the polymerization of Bd with the Co(acac)3‐MAO catalyst. The effects of reaction temperature, Bd concentration, and the MAO/Co molar ratio on the cis‐1,4 microstructure and high molecular weight polymer in the polymerization of Bd with Co(acac)3‐MAO catalyst were observed. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 2793–2798, 2001  相似文献   

8.
Styrene (St) was polymerized with α,α′‐bis(2′,2′,6′,6′‐tetramethyl‐1′‐piperidinyloxy)‐1,4‐diethylbenzene ( 1 ) as an initiator (bulk, [St]/] 1 ] = 570) at 120 °C for 5.0 h to obtain polystyrene having 2,2,6,6‐tetramethylpiperidiloxy moieties on both sides of the chain ends ( 2 ) with a number‐average molecular weight (Mn) of 14,300 and a polydispersity index [weight‐average molecular weight/number‐average molecular weight (Mw/Mn)] of 1.14. 4‐Vinylbenzyl glucoside peracetate ( 3a ) was polymerized with 2 as a macromolecular initiator and dicumyl peroxide (DCP) as an accelerator in chlorobenzene at 120 °C. The polymerization with the [ 3a ]/[ 2 ]/[DCP] ratio of 30/1/1.2 for 5 h afforded a product in a yield of 73%; it was followed by purification with preparative size exclusion chromatography to provide the ABA triblock copolymer containing the pendant acetyl glucose on both sides of the chain ends ( 4a ; Mn = 21,000, Mw/Mn = 1.16). Similarly, the polymerization of 4‐vinylbenzyl maltohexaoside peracetate produced the ABA triblock copolymer containing the pendant acetyl maltohexaose on both side of the chain end ( 4b ; Mn = 31,800, Mw/Mn = 1.11). Polymers 4a and 4b were modified by deacetylation into amphiphilic ABA triblock copolymers containing the pendant glucose and maltohexaose as hydrophilic segment, 5a and 5b , respectively. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 3978–3985, 2006  相似文献   

9.
New block copolymers Polystyrene‐b‐poly (2,2,2‐trifluoroethyl acrylate)‐b‐Polystyrene (PS‐PTFEA‐PS) with controlled molecular weight (Mn=5000‐11000 g?mol?1) and narrow molecular weight distribution (Mw/Mn=1.13‐1.17) were synthesized via RAFT polymerization. The molecular structure and component of PS‐PTFEA‐PS block copolymers were characterized through 1H NMR, 19F NMR, GPC, FT‐IR and elemental analysis. The porous films of such copolymers with average pore size of 0.80‐1.34 μm and good regularity were fabricated via a static breath‐figure (BF) process. The effects of solvent, temperature, and polymer concentration on the surface morphology of such film were investigated. In addition, microstructured spheres and fibers of such block copolymers were fabricated by electrospinning process and observed by scanning electron microscopy (SEM). Furthermore, the hydrophobicity of porous films, spheres, and fibers was investigated. The porous film showed a good hydrophobicity with the water‐droplet contact angles of 129°, and the fibers showed higher hydrophobicity with the water‐droplet contact angles of 142°. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016 , 54, 678–685  相似文献   

10.
The anionic polymerization of butadiene initiated with 1,4‐dilithio‐1,1,4,4‐tetraphenylbutane (LiTPB) in diethyl ether (DEE) gives polybutadiene (PBD) with high 1,2 content (>70%), narrow polydispersities (1.04 < Mw/Mn < 1.20), and predicted molecular weights. In THF, this polymerization does not work very well. After removal of DEE and addition of THF, the PBD dianion is end capped quantitatively by addition of 1,1‐diphenylethylene (DPE) to give the diphenylalkyl end capped PBD dianion. Subsequent addition of methyl methacrylate at low temperatures results in the formation of well‐defined PMMA‐b‐PBD‐b‐PMMA triblock copolymers. The results are accounted for by taking into account the effects of Li ion solvation on the BD initiation and end capping of the PBD anion by DPE. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 2198–2206, 2009  相似文献   

11.
Novel copolycarbonates containing 1,4:3,6‐dianhydro‐D ‐glucitol or 1,4:3,6‐dianhydro‐D ‐mannitol units, with various methylene chain lengths, were synthesized by bulk and solution polycondensations, of several combinations of carbonate‐modified sugar derivatives and aliphatic diols. Bulk polycondensations of 1,4:3,6‐dianhydro‐2,5‐bis‐O‐(phenoxycarbonyl)‐D ‐glucitol or 1,4:3,6‐dianhydro‐2,5‐bis‐O‐(phenoxycarbonyl)‐D ‐mannitol with four α,ω‐alkanediols having methylene chain lengths of 4, 6, 8, and 10, respectively, at 180 °C afforded the corresponding copolycarbonates with number‐average molecular weight (Mn) values up to 19.2 × 103. 13C NMR analysis disclosed that these polymers had scrambled structures in which the sugar carbonate and aliphatic carbonate moieties were nearly randomly distributed along a polymer chain. However, solution polycondensations between 1,4:3,6‐dianhydro‐2,5‐bis‐O‐(p‐nitrophenoxycarbonyl)‐D ‐glucitol or 1,4:3,6‐dianhydro‐2,5‐bis‐O‐(p‐nitrophenoxycarbonyl)‐D ‐mannitol, and the α,ω‐alkanediols in sulfolane or dimethyl sulfoxide at 60 °C gave well‐defined copolycarbonates having regular structures consisting of alternating sugar carbonate and aliphatic carbonate moieties with Mn values up to 33.8 × 103. Differential scanning calorimetry demonstrated that all the copolycarbonates were amorphous with glass‐transition temperatures ranging from 1 to 65 °C, which decreased with increasing lengths of the methylene chain of the aliphatic diols. Additionally, all the copolycarbonates were stable up to 310–330 °C as estimated by thermogravimetric analysis. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 2312–2321, 2003  相似文献   

12.
The results of an interlaboratory or round‐robin experiment in high‐temperature gel permeation chromatography (HT‐GPC) analysis are presented. The intention was to determine and raise awareness of interlaboratory reproducibility of HT‐GPC techniques. Fifteen laboratories performed analyses of five polyethylene samples and standards SRM 1475 and 1476. Reproducibility, as measured by the interlaboratory standard deviation (sLAB), was greatly influenced by the breadth of the molecular weight distribution (MWD) and branching. The sLAB values for the weight‐average molecular weight (Mw) of linear polyethylenes of narrow and broad MWDs were 4 and 14%, respectively. For branched polymers, GPC viscometry methods are shown to measure significantly higher molecular weights than the noncoupled GPC method, with higher variance. For branched polyethylenes measured with GPC viscometry, the reproducibility of Mw was characterized by sLAB = 18%. Reproducibility of the SRM 1475 standard was better than for unknowns. The results for branched standard SRM 1476 emphasize the important role of the detection method in GPC but call into question the use of this material as a molecular weight standard. For single‐site polyethylene, only a handful of labs measured an MWD that closely matched the Flory distribution. Qualitatively, the responses indicate that many variations in instrument and analytical methods exist among laboratories; this is partly a reflection of the development and refinements that this technique must yet undergo before a truly standard method is widely accepted and practiced. © 2002 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 40: 905–921, 2002  相似文献   

13.
We have demonstrated a direct arylation polycondensation of 3,4‐ethylenedioxythiophene with 2,7‐dibromo‐9,9‐dioctylfluorene using palladium on carbon (Pd/C) as a catalyst. Pd/C is a low‐cost solid‐supported palladium catalyst, giving one of the effective catalytic systems for direct arylation. The Pd/C‐catalyzed direct arylation polycondensation with acetic acid/potassium carbonate in N,N‐dimethylacetamide furnished a high molecular weight π‐conjugated alternating copolymer of EDOT‐fluorene (Mn = 89,300, Mw/Mn = 3.27) in high yield. The polycondensation of EDOT with various dibromoarenes was also achieved, giving EDOT‐carbazole, EDOT‐dialylamine, and EDOT‐bithiophene polymers. Optical and electrochemical properties of the polymers were also discussed. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016 , 55, 1183–1188  相似文献   

14.
Star‐shaped polybutadiene stars were synthesized by a convergent coupling of polybutadienyllithium with 4‐(chlorodimethylsilyl)styrene (CDMSS). CDMSS was added slowly and continuously to the living anionic chains until a stoichiometric equivalent was reached. Gel permeation chromatography‐multi‐angle laser light scattering (GPC‐MALLS) was used to determine the molecular weights and molecular weight distribution of the polybutadiene polymers. The number of arms incorporated into the star depended on the molecular weight of the initial chains and the rate of addition of the CDMSS. Low molecular weight polybutadiene arms (Mn = 640 g/mol) resulted in polybutadiene star polymers with an average of 12.6 arms, while higher molecular weight polybutadiene arms (Mn = 16,000 g/mol) resulted in polybutadiene star polymers with an average of 5.3 arms. The polybutadiene star polymers exhibited high 1,4‐polybutadiene microstructure (88.3–93.1%), and narrow molecular weight distributions (Mw/Mn = 1.11–1.20). Polybutadiene stars were subsequently hydrogenated by two methods, heterogeneous catalysis (catalytic hydrogenation using Pd/CaCO3) or reaction with p‐toluenesulfonhydrazide (TSH), to transform the polybutadiene stars into polyethylene stars. The hydrogenation of the polybutadiene stars was found to be close to quantitative by 1H NMR and FTIR spectroscopy. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 828–836, 2006  相似文献   

15.
Atom transfer radical polymerization with activators generated by electron transfer initiating/catalytic system (AGET ATRP) of 2‐hydroxyethyl methacrylate (HEMA) was carried out in inverse miniemulsion. Water‐soluble ascorbic acid as a reducing agent and mono‐ and difunctional poly(ethylene oxide)‐based bromoisobutyrate (PEO‐Br) as a macroinitiator were used in the presence of CuBr2/tris[(2‐pyridyl)methyl]amine (TPMA) and CuCl2/TPMA complexes. The use of poly(ethylene‐co‐butylene)‐block‐poly(ethylene oxide) as a polymer surfactant resulted in the formation of stable HEMA cyclohexane inverse dispersion and PHEMA colloidal particles. All polymerizations were well‐controlled, allowing for the preparation of well‐defined PEO‐PHEMA and PHEMA‐PEO‐PHEMA block copolymers with relatively high molecular weight (DP > 200) and narrow molecular weight distribution (Mw/Mn < 1.3). These block copolymers self‐assembled to form micellar nanoparticles being 10–20 nm in diameter with uniform size distribution, and aggregation number of ~10 confirmed by atomic force microscopy and transmission electron microscopy. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 4764–4772, 2007  相似文献   

16.
Cationic emulsions of triblock copolymer particles comprising a poly(n‐butyl acrylate) (PnBA) central block and polystyrene (PS) outer blocks were synthesized by activator generated by electron transfer (AGET) atom transfer radical polymerization (ATRP). Difunctional ATRP initiator, ethylene bis(2‐bromoisobutyrate) (EBBiB), was used as initiator to synthesize the ABA type poly(styrene‐bn‐butyl acrylate‐b‐styrene) (PS‐PnBA‐PS) triblock copolymer. The effects of ligand and cationic surfactant on polymerizations were also discussed. Gel permeation chromatography (GPC) was used to characterize the molecular weight (Mn) and molecular weight distribution (MWD) of the resultant triblock copolymers. Particle size and particle size distribution of resulted latexes were characterized by dynamic light scattering (DLS). The resultant latexes showed good colloidal stability with average particle size around 100–300 nm in diameter. Glass transition temperature (Tg) of copolymers was studied by differential scanning calorimetry (DSC). © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016 , 54, 611–620  相似文献   

17.
A series of monodisperse (Mw/Mn < 1.1) poly(ferrocenyldimethylsilane)s was prepared with number‐averaged degrees of polymerization, 〈zn, of 9, 33, 206, and 506 ( 2 – 5 , respectively), as determined by gel permeation chromatography (GPC). The polymers were studied by small‐angle neutron scattering (SANS) in solution with the aim of obtaining the radius of gyration, Rg, the weight‐averaged molecular weight, Mw, and the polydispersity index, Mw/Mn. Data were collected over the range 0.008 < Q?1 < 0.5 and for a series of concentrations (weight fraction, w = 0.0063, 0.0125, 0.025, and 0.05). The scattered intensity, I(Q), was fitted to a model based on a Schultz–Zimm distribution of isolated chains with excluded volume. A comparison of the molecular weight and size data determined by GPC and SANS indicated an acceptable agreement between the values for Rg, Mw and Mw/Mn. The results of this study demonstrate the potential utility of SANS to fully characterize metallopolymers, and other polymer systems where traditional methods cannot be applied. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013 , 51, 4011–4020  相似文献   

18.
In this study, we demonstrate how the intrinsic properties of a polymer can influence the electrical characteristics of organic field‐effect transistors (OFETs). OFETs fabricated with three batches of poly[2‐methoxy,5‐(3′,7′‐dimethyl‐octyloxy)]‐p‐phenylene vinylene (MDMO‐PPV) were investigated. The properties of the polymers were initially investigated using Fourier transform infrared spectroscopy (FTIR), impedance spectroscopy (IS), gel permeation chromotography (GPC), and cyclic voltammetry (CV), respectively. The structure and purity of the polymer batches were found to be very comparable, but the molecular weight (Mn and Mw) and polydispersity (PDI = Mw/Mn), varied between the samples and the HOMO and LUMO levels of the polymers were found to depend on the molecular weight properties. OFETs were then fabricated with the polymers and electrically characterized. It was observed that the channel current and the field‐effect mobility increase with increasing polymer molecular weight. The output characteristics of the transistors, on the other hand, were found to depend on the PDI of the polymer. Saturation of the channel current occurs at higher source–drain voltages and short‐channel behavior was observed to start at longer channel lengths for polymers with a higher PDI. This behavior is observed to be thickness dependent, and the short‐channel behavior was more pronounced for thicker MDMO‐PPV films. These results are explained in terms of influences of chain packing and ordering and high bulk currents on the FET output and transistor parameters. © 2011 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 50: 117–124, 2012  相似文献   

19.
High molecular weight star‐shaped polystyrenes were prepared via the coupling of 2,2,6,6‐tetramethyl‐1‐piperidinyloxy (TEMPO) terminated polystyrene oligomers with divinylbenzene (DVB) in m‐xylene at 138 °C. The optimum ratio of the coupling solvent (m‐xylene) to divinylbenzene was determined to be 9 to 1 based on volume. Linear polystyrene oligomers (Mn = 19,300 g/mol, Mw/Mn = 1.10) were prepared in bulk styrene using benzoyl peroxide in the presence of TEMPO at approximately 130 °C under an inert atmosphere. Coupling of the TEMPO‐terminated oligomers under optimum conditions resulted in a product with a number average molecular weight exceeding 300,000 g/mol (Mw/Mn = 3.03) after 24 h, suggesting the formation of relatively well‐defined star‐shaped polymers. Additionally, the intrinsic viscosities of the star‐shaped products were lower than calculated values for linear analogs of equivalent molecular weight, which further supported the formation of a star‐shaped architecture. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 39: 216–223, 2001  相似文献   

20.
Polymerizations of 1,3‐dienes using in situ generated catalyst [(2‐methallyl)Ni][B(ArF)4], 6 , (ArF = 3,5‐bis(trifluoromethyl)phenyl) as well as [(2‐methallyl)Ni(mes)][B(ArF)4], 14 , (mes = mesitylene) are reported. Highly sensitive complex 6 polymerizes butadiene (BD) at –30 °C to yield polybutadiene with a Mn of ca. 10 K and 94% cis‐1,4‐enchainment while less reactive isoprene (IP) was polymerized at 23 °C to yield polyisoprene with Mn ca. 7 K. Complex 6 was also shown to polymerize a functionalized diene, 2,3‐bis(4‐trifluoroethoxy‐4‐oxobutyl)‐1,3‐BD, to polymer with Mn = 113 K. The stable and readily isolated arene complex 14 initiates BD and IP polymerizations at somewhat higher temperatures relative to 6 and delivers polymers with higher molecular weights. Complex [(allyl)Ni(mes)][B(ArF)4], 13 , catalyzes polymerization of styrene to yield polystyrene with high conversion, Mn's = ca. 6 K and MWD = 2. The π‐benzyl complex [(η3‐1‐methylbenzyl)Ni(mes)] [B(ArF)4], 19 , was detected as an intermediate following chain transfer by in situ NMR studies. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 1901–1912, 2010  相似文献   

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