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1.
Salen‐zinc complexes (Zn/ 1 R ) thermal‐latently catalyzed the polyaddition of a diepoxide ( 2 ) with a difunctional hemiacetal ester ( 3 ), which proceeded at moderate temperatures (100–150 °C) for curing of mixtures containing monomers and initiators. The catalytic activities of Zn/ 1 R depended on the Lewis acidities of the complexes controlled by the electronic character of the salen ligands. For example, Zn/ 1 3,5‐Cl bearing four electron‐withdrawing chlorine atoms initiated the polyaddition at the lowest temperature (100 °C), and Zn/ 1 OMe bearing two electron‐donating methoxy groups initiated the polyaddition at 120 °C. The Lewis acidities of the complexes were evaluated by NMR and IR spectroscopies and computational calculation. The polyadditions with the salen‐zinc complexes proceeded quantitatively at 150 °C, and the use of a tri‐functional hemiacetal ester ( 7 ) with 2 afforded the corresponding networked polymer. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 1427–1439, 2008  相似文献   

2.
Enolic Schiff base zinc (II) complex 1 was synthesized. XRD revealed 1 was a novel crown‐like macrocycle structure consisted of hexanuclear units of (LZnEt)6 via the coordination chelation between the Zn atom and adjacent amine nitrogen atom. Further reaction of 1 with one equivalent 2‐propanol at RT produced Zn‐alkoxide 2 by in situ alcoholysis. Complex 2 was used as an initiator to polymerize rac‐lactide in a controlled manner to give heterotactic enriched polylactide. Factors that influenced the polymerization such as the polymerization time and the temperature as well as the monomer concentration were discussed in detail in this paper. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 643–649, 2008  相似文献   

3.
Magnesium (Mg) and zinc (Zn) complexes incorporating tridentate anilido‐aldimine ligand, (E)‐2, 6‐diisopropyl‐N‐(2‐((2‐(piperidin‐1‐yl)ethylimino)methyl)phenyl)aniline ( AA Pip ‐H, 1 ), were synthesized and structurally characterized. The reaction of AA Pip ‐H ( 1 ) with MgnBu2 or ZnEt2 in equivalent proportions afforded the monomeric complex [( AA Pip )MgnBu] ( 2 ) or [( AA Pip )ZnEt] ( 3 ), respectively. The coordination modes of these complexes differ in the solid state: Mg complex 2 shows a four‐coordinated and distorted tetrahedral geometry, whereas Zn complex 3 adopts a trigonal planar geometry with a three‐coordinated Zn center. Complexes 2 and 3 are efficient catalysts for the ring‐opening polymerization of β‐butyrolactone (β‐BL) in the presence of 9‐anthracenemethanol (9‐AnOH). The polymerization of β‐BL with the Zn catalyst system is demonstrated in a living fashion with a narrow polydispersity index, PDI = 1.01–1.10. The number‐averaged molecular weight (Mn) of the produced poly(3‐hydroxybutyrate) (PHB) is quite close to the expected Mn over diverse molar ratios of monomer to 9‐AnOH. A greater ratio of monomer to alcohol catalyzed by Zn complex 3 served to form PHB with a large molecular weight (Mn > 60000). An effective method to prepare PHB‐b‐PCL and PEG‐b‐PHB by the ring‐opening copolymerization of β‐BL catalyzed by zinc complex 3 is reported. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010  相似文献   

4.
A series of efficient catalysts, based on zinc alkoxides coordinated with NNO‐tridentate Schiff‐base ligands (L1H‐L6H), for ring opening polymerization of L ‐lactide have been prepared. The reactions of diethyl zinc (ZnEt2) with L1H‐L6H yielded [(μ‐L)ZnEt]2 ( 1a–6a ), respectively. Further reaction of compounds 1a–6a with benzyl alcohol (BnOH) produced the corresponding compounds of [LZn(μ‐OBn)]2 ( 1b–6b), respectively. X‐ray crystal structural studies reveal that all of these compounds 1a–6a are dimeric bridging through the phenolato oxygen atoms of the Schiff‐base ligand. However, the molecular structures of 1b–6b show a dimeric character bridging through the benzylalkoxy oxygen atoms. Ring‐opening polymerization of L ‐lactide, initiated by 1b–6b , proceeds rapidly with good molecular weight control and yields polymer with a very narrow molecular weight distribution. Experimental results show that the substituents on the imine carbon of the NNO‐ligand affect the reactivity of zinc complexes dramatically. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 6466–6476, 2008  相似文献   

5.
Thermally latent reaction of a copolymer ( P1 ) bearing hemiacetal ester and n‐butyl methacrylate moieties and glycidyl phenyl ether ( 2 ) was catalyzed by bis(p‐methoxybenzylidene)‐1,2‐diiminoethane/zinc chloride complex (ZnCl2/ 3 ) at 30–150 °C for 6 h. No reaction of P1 and 2 took place below 70 °C, and it smoothly proceeded above 120 °C. The latencies and activities mean that ZnCl2/ 3 meets both the high latencies at ambient conditions and the high activities at desired temperatures. Thermal crosslinking reaction employing multifunctional derivatives was carried out using ZnCl2/ 3 at 140 °C for 6 h to afford a networked polymer in high yields. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 3682–3689, 2008  相似文献   

6.
Although zinc? cobalt (III) double metal cyanide complex (Zn? Co (III) DMCC) catalyst is a highly active and selective catalyst for carbon dioxide (CO2)/cyclohexene oxide (CHO) copolymerization, the structure of the resultant copolymer is poorly understood and the catalytic mechanism is still unclear. Combining the results of kinetic study and electrospray ionization‐mass spectrometry (ESI‐MS) spectra for CO2/CHO copolymerization catalyzed by Zn? Co (III) DMCC catalyst, we disclosed that (1) the short ether units were mainly generated at the early stage of the copolymerization, and were hence in the “head” of the copolymer and (2) all resultant PCHCs presented two end hydroxyl (? OH) groups. One end ? OH group came from the initiation of zinc? hydroxide (Zn? OH) bond and the other end ? OH group was produced by the chain transfer reaction of propagating chain to H2O (or free copolymer). Adding t‐BuOH (CHO: t‐BuOH = 2:1, v/v) to the reaction system led to the production of fully alternating PCHCs and new active site of Zn? Ot‐Bu, which was proved by the observation of PCHCs with one end ? Ot‐Bu (and ? OCOOt‐Bu) group from ESI‐MS and 13C NMR spectra. Moreover, Zn?OH bond in Zn? Co (III) DMCC catalyst was also characterized by the combined results from FT‐IR, TGA and elemental analysis. This work provided new evidences that CO2/CHO copolymerization was initiated by metal? OH bond. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012  相似文献   

7.
Schiff‐base–zinc halide complexes (ZnX2/ 1 ) thermal‐latently catalyze the reaction of glycidyl phenyl ether (2) and 1‐propoxyethyl 2‐ethylhexanoate (3) that proceeds at moderately elevated temperatures. The catalysis by the ZnX2/ 1 complexes proceeds via the thermal dissociation of 3 to produce the corresponding carboxylic acid that nucleophilically attacks 2 predominantly over the thermally dissociated vinyl ether. ZnX2/ 1 complexes catalyze both the dissociation of 3 to produce the carboxylic acid intermediate and its addition to 2 . Although conventional latent catalysts for this reaction exhibit Lewis acidities under ambient conditions that are responsible to the gradual degradation of hemiacetal esters and the polymerization of epoxides, a mixture of 2 , 3 , and ZnX2/ 1 can be stored for 3 months at ambient conditions. The stored mixture is as active as the freshly prepared mixture, keeping the excellent activity and latency of ZnX2/ 1 . As well as the model reaction, the thermally latent polyaddition of bisphenol A diglycidyl ether (9) and di‐1‐propoxyethyl adipate (10) is also promoted with ZnCl2/ 1 at a moderate elevated temperature. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 3370–3379, 2007  相似文献   

8.
Ring‐opening polymerization of ?‐caprolactone was carried out smoothly and effectively with constant microwave powers of 170, 340, 510, and 680 W, respectively, with a microwave oven at a frequency of 2.45 GHz. The temperature of the polymerization ranged from 80 to 210 °C. Poly(?‐caprolactone) (PCL) with a weight‐average molar mass (Mw) of 124,000 g/mol and yield of 90% was obtained at 680 W for 30 min using 0.1% (mol/mol) stannous octanoate as a catalyst. When the polymerization was catalyzed by 1% (w/w) zinc powder, the Mw of PCL was 92,300 g/mol after the reaction mixture was irradiated at 680 W for 270 min. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 1749–1755, 2002  相似文献   

9.
Polymer‐supported pyridinium salts, prepared by quaternarization of crosslinked poly(4‐vinylpyridine) with alkyl halides, effectively catalyze the reaction of carbon dioxide (1 atm) and glycidyl phenyl ether (GPE) to afford the corresponding five‐membered cyclic carbonate (4‐phenoxymethyl‐1,3‐dioxolan‐2‐one). Poly(4‐vinylpyridine) quarternarized with alkyl bromides show high catalytic activities, and the reaction of carbon dioxide (1 atm) and GPE at 100 °C affords 4‐phenoxymethyl‐1,3‐dioxolan‐2‐one quantitatively in 6 h. The rate constant in the reaction of GPE and carbon dioxide in N‐methyl pyrrolidinone using poly(4‐vinylpyridine) quarternarized with n‐butyl bromide (kobs = 102 min?1) is almost comparable with those for homogeneous catalysts with good activities (e.g., LiI), and the rate of the reaction obeys the first‐order kinetics. A used catalyst may be recovered by centrifugation, and the recycled catalyst also promotes the reaction of GPE and carbon dioxide. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 5673–5678, 2007  相似文献   

10.
Poly(p‐dioxanone) with an inherent viscosity of over 1 dL/g has been synthesized using the cyclic tin alkoxide 1‐di‐n‐butyl‐1‐stanna‐2,5‐dioxacyclopentane as initiator. Poly(p‐dioxanone) was synthesized in bulk and the results have been compared with polymerizations using tin (II) 2‐ethylhexanoate (Sn(Oct)2) as catalyst. Sn(Oct)2 has often been reported to be an effective catalyst for the synthesis of poly(p‐dioxanone), but here it is compared with an initiator which is less prone to catalyze transesterification reactions. The results demonstrate that the cyclic tin initiator is a promising alternative for the synthesis of poly(p‐dioxanone) with a high inherent viscosity. Poly(p‐dioxanone) is a polymer with mechanical properties and a degradation rate suitable for tissue engineering applications. Both the cyclic tin initiator and Sn(Oct)2 gave, under some reaction conditions, inherent viscosities around 1 dL/g. The best polymer synthesized using the cyclic tin initiator had a strain‐at‐break of 515% and a stress‐at‐break of 43 MPa. The inherent viscosity of this polymer was 1.16 dL/g, while Sn(Oct)2 resulted in a polymer with an inherent viscosity less than 0.4 dL/g under the same reaction conditions. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 5552–5558, 2007  相似文献   

11.
Cobalt porphyrin complex (TPPCoIIIX) (TPP = 5, 10, 15, 20‐Tetraphenyl‐ porphyrin; X = halide) in combination with ionic organic ammonium salt was used for the regio‐specific copolymerization of propylene oxide and carbon dioxide. A turnover frequency of 188 h?1 was achieved after 5 h, and the byproduct propylene carbonate was successfully controlled to below 1%, where the obtained poly(propylene carbonate) (PPC) showed number average molecular weight (Mn) of 48 kg/mol, head‐to‐tail content of 93%, and carbonate linkage of over 99%. When the polymerization time was prolonged to 24 h, PPC with Mn over 115 kg/mol and head‐to‐tail linkage maintaining 90% was prepared, whose glass transition temperature reached 44.5 °C. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 5959–5967, 2008  相似文献   

12.
Zinc catalysts incorporated by imino‐benzotriazole phenolate ( IBTP ) ligands were synthesized and characterized by single‐crystal X‐ray structure determinations. The reaction of the ligand precursor ( C1DMeIBTP ‐H or C1DIPIBTP ‐H) with diethyl zinc (ZnEt2) in a stoichiometric proportion in toluene furnished the di‐nuclear ethyl zinc complexes [(μ‐ C1DMeIBTP )ZnEt]2 ( 1 ) and [(μ‐ C1DIPIBTP )ZnEt]2 ( 2 ). The tetra‐coordinated monomeric zinc complex [( C1PhIBTP )2Zn] ( 3 ) or [( C1BnIBTP )2Zn] ( 4 ) resulted from treatment of C1PhIBTP ‐H or C1BnIBTP ‐H as the pro‐ligand under the similar synthetic method with ligand to metal precursor ratio of 2:1. Single‐crystal X‐ray diffraction of bimetallic complexes 1 and 2 indicates that the C1DMeIBTP or C1DIPIBTP fragment behaves a NON‐tridentate ligand to coordinate two metal atoms. Catalysis for ring‐opening polymerization (ROP) of ε‐caprolactone (ε‐CL), β‐butyrolactone (β‐BL), and lactide (LA) of complexes 1 and 2 was systematic studied. In combination with 9‐anthracenemethanol (9‐AnOH), Zn complex 1 was found to polymerize ε‐CL, β‐BL, and L‐LA with efficient catalytic activities in a controlled character. This study also compared the reactivity of these ROP monomers with different ring strains by Zn catalyst 1 in the presence of 9‐AnOH. Additionally, Zn complex 1 combining with benzoic acid was demonstrated to be an active catalytic system to copolymerize phthalic anhydride and cyclohexene oxide. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016 , 54, 714–725  相似文献   

13.
A novel primary amine‐containing monomer, 1‐(3′‐aminopropyl)‐4‐acrylamido‐1,2,3‐triazole hydrochloride (APAT), was prepared from N‐propargylacrylamide and 3‐azidopropylamine hydrochloride via copper‐catalyzed Huisgen 1,3‐dipolar cycloaddition (click reaction). Poly(N‐isopropylacrylamide)‐b‐poly(1‐(3′‐aminopropyl)‐4‐acrylamido‐1,2,3‐triazole hydrochloride), PNIPAM‐b‐PAPAT, was then synthesized via consecutive reversible addition‐fragmentation chain transfer polymerizations of N‐isopropylacrylamide and APAT. In aqueous solution, the obtained thermoresponsive double hydrophilic block copolymer dissolves molecularly at room temperature and self‐assembles into micelles with PNIPAM cores and PAPAT shells at elevated temperature. Because of the presence of highly reactive primary amine moieties in PAPAT block, two types of covalently stabilized nanoparticles namely core crosslinked and shell crosslinked micelles with ‘inverted’ core‐shell nanostructures were facilely prepared upon the addition of glutaric dialdehyde at 25 and 50 °C, respectively. In addition, the obtained structure‐fixed micelles were incorporated with gold nanoparticles via in situ reduction of preferentially loaded HAuCl4. High resolution transmission electron microscopy revealed that gold nanoparticles can be selectively loaded into the crosslinked cores or shells, depending on the micelle templates employed. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 6518–6531, 2008  相似文献   

14.
Poly[2‐(2′‐ethylhexyloxy)‐5‐methoxy‐1,4‐phenylene‐(1‐cyanovinylene)] MEH‐CN‐PPV and its all‐trans model compound 1,4‐bis(α‐cyanostyryl)‐2‐(2‐ethylhexyloxy)‐5‐methyloxybenzene were synthesized via Knoevenagel condensation. All‐cis isomer and cistrans isomer of 1,4‐bis(α‐cyanostyryl)‐2‐(2‐ethylhexyloxy)‐5‐methyloxybenzene were prepared by the photoisomerization reaction. Comparison of the 1H NMR spectra between MEH‐CN‐PPV and three model compounds proved the occurrence of cis‐vinylene in the backbone of MEH‐CN‐PPV. According to the ratio between the cis‐vinylene signal and trans‐vinylene signal, the content of the cis‐vinylene could be estimated to be 15% in MEH‐CN‐PPV. This large cis‐vinylene content came from the rapid photochemical isomerization of cyanovinylene and was likely relative to the poor electroluminescence property of MEH‐CN‐PPV. © 2008 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 46: 1105–1113, 2008  相似文献   

15.
The proposed mechanism of initiation and course of ring‐opening polymerization of cyclic trimethylene carbonate (TMC) involving zinc(II) acetylacetonate is in accordance with the mechanism of monomer activation. At the first stage of the process, coordination of carbonate to Zn(Acac)2 · H2O complex occurs with the release of weakly coordinated water molecules. This free water molecule reacts with active TMC–Zn(Acac)2 complex. The reaction results in the formation of propanediol and CO2 emission. During further stages of the investigated process, the formed propanediols, or later the oligomeric diols produced with polymerization, are cocatalysts of the chain propagation reaction. The chain propagation occurs because of repeating activation of the TMC monomer through the creation of an active structure resulting in the exchange/transfer reaction between the zinc complex and the monomer, with its following attachment to the hydroxyl groups, carbonate ring opening, and formation of the carbonic unit of polymer chain. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011  相似文献   

16.
Poly(ethylene‐g‐styrene) and poly(ethylene‐g‐methyl methacrylate) graft copolymers were prepared by atom transfer radical polymerization (ATRP). Commercially available poly(ethylene‐co‐glycidyl methacrylate) was converted into ATRP macroinitiators by reaction with chloroacetic acid and 2‐bromoisobutyric acid, respectively, and the pendant‐functionalized polyolefins were used to initiate the ATRP of styrene and methyl methacrylate. In both cases, incorporation of the vinyl monomer into the graft copolymer increased with extent of the reaction. The controlled growth of the side chains was proved in the case of poly(ethylene‐g‐styrene) by the linear increase of molecular weight with conversion and low polydispersity (Mw /Mn < 1.4) of the cleaved polystyrene grafts. Both macroinitiators and graft copolymers were characterized by 1H NMR and differential scanning calorimetry. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 2440–2448, 2000  相似文献   

17.
The effects of Br connected groups on atom transfer nitroxide radical coupling (ATNRC) reaction were investigated. Two precursors methoxyl poly(ethylene oxide)‐b‐poly(ethylene oxide‐co‐2‐bromoiso butyryloxy glycidyl ether) (mPEO‐b‐Poly(EO‐co‐BiBGE)) and methoxyl poly(ethylene oxide)‐b‐poly(2‐bromoiso butyryloxy glycidyl ether) (mPEO‐b‐Poly(BiBGE)) with different ? C(CH3)2Br density were designed and synthesized firstly, and then ATNRC reaction were completed between these precursors and 2,2,6,6‐tetramethylpiperidinyl‐1‐oxy poly(ε‐caprolactone) (TEMPO‐PCL) in the presence or absence of St monomers, respectively. The results showed that the structure of Br connected groups showed an important effect on ATNRC reaction, and the ATNRC reaction with high efficiency could be realized by transforming the higher active Br connected groups into the lower one by the addition of small amount of St monomers. The final comb‐like block copolymers mPEO‐b‐[Poly(EO‐co‐Gly)‐g‐(St1.8b‐PCL)] and mPEO‐b‐[Poly(Gly)‐g‐(St2.4b‐PCL)] with high coupling efficiency were obtained by this strategy. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 1633–1640, 2010  相似文献   

18.
A new thermal latent hydrosilylation catalyst on the basis of H2PtCl6 and polystyrene derivatives having propargyl moieties is described. The polystyrene derivatives having various propargyl moieties were obtained by the reaction of propargyl alcohols with poly(p‐chloromethylstyrene) or its copolymer with styrene. The polymer‐supported platinum catalysts were prepared by aging H2PtCl6 with these polymers in tetrahydrofuran at 30 °C for 12 h. In the presence of the polymers, the hydrosilylation activity of H2PtCl6 was found to be controlled thermally in the model reaction of trimethylsilane and triethylvinylsilane. Effective control of the crosslinking reaction of silicone resin was also achieved by using these latent catalyst systems. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 35–42, 2000  相似文献   

19.
The monomer 5‐ethynyl‐N,N‐dimethylnaphthalen‐1‐amine ( 2 ) was satisfactorily obtained by a heterocoupling reaction between 5‐iodo‐(N,N‐dimethyl)naphthalen‐1‐amine and 2‐methyl‐3‐butyn‐2‐ol catalyzed by a palladium–copper system and followed by acetone elimination. Poly(5‐ethynyl‐N,N‐dimethylnaphthalen‐1‐amine) was isolated by the reaction of 2 in the presence of homogeneous rhodium and palladium complexes. On the basis of the spectroscopic data, the polymer always showed a cis–transoidal, stereoregular structure. Moreover, only with the rhodium catalyst in methanol was a dimeric product isolated in a very low yield, having a conjugated terminal ene–yne structure, which permitted the consideration of a metallated chain‐transfer intermediate in the polymer propagation. The kinetics of the catalyzed reaction were analyzed. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 437–446, 2007  相似文献   

20.
Tetraphenylporphyrin‐end‐functionalized polycyclohexane (H2TPP‐PCHE) and its metal complexes (MTPP‐PCHE) were synthesized as the first successful example of porphyrin‐end‐functionalized transparent and stable polymers with a well‐controlled and defined polymer chain structure. Chloromethyl‐end‐functionalized poly(1,3‐cyclohexadiene) (CM‐PCHD) was synthesized as prerequisite prepolymer by the postpolymerization reaction of poly(1,3‐cyclohexadienyl)lithium and chloro(chloromethyl)dimethylsilane. CM‐end‐functionalized PCHE (CM‐PCHE) was prepared by the complete hydrogenation of CM‐PCHD with p‐toluenesulfonyl hydrazide. H2TPP was incorporated onto the polymer chain end by the addition of 5‐(4‐hydroxyphenyl)‐10,15,20‐triphenylporphyrin to CM‐PCHE. The complexation of H2TPP‐PCHE and Zn(OAc)2 (or PtCl2) yielded a zinc (or platinum) complex of H2TPP‐PCHE. H2TPP‐PCHE and MTPP‐PCHE were readily soluble in common organic solvents, and PCHE did not inhibit the optical properties of the H2TPP, ZnTPP, and PtTPP end groups. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011  相似文献   

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