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1.
1,9-Decadiene/propylene copolymers were obtained with isolated metallocenes and with a binary metallocene catalyst system activated by methylaluminoxane. The metallocenes under investigation were syndiospecific diphenylmethyl(cyclopentadienyl)(9-fluorenyl)zirconium dichloride (1) and isospecific rac-dimethylsilylbis(4-tert-butyl-2-methyl-cyclopentadienyl)zirconium dichloride (2). A copolymer structure, in which 1,9-decadiene linked isotactic and syndiotactic polymer chains, was obtained when copolymerisation was started with catalyst 2 at 80 °C followed by injection of catalyst 1 and instantaneous lowering of polymerisation temperature to 40 °C after 15 min of polymerisation. The copolymer was also shown to work as a compatibiliser in a blend of syndiotactic and isotactic polypropylene. We propose that catalyst 2 incorporates 1,9-decadiene into the isotactic main chain without any significant crosslinking within the first 15 min of polymerisation at 80 °C and the produced isotactic macromonomers are further incorporated at 40 °C into the syndiotactic main chain in polymerisation with catalyst 1.  相似文献   

2.
Naofumi Naga  Yukio Imanishi 《Polymer》2002,43(8):2133-2139
Copolymerization of propylene and cyclopentene (CPE) was carried out using as a catalyst isospecific rac-ethylenebis(indenyl)zirconium dichloride (1), rac-dimethylsilylenebis(indenyl)zirconium dichloride (2), rac-dimethylsilylenebis(2-methylindenyl)zirconium dichloride (3), or syndiospecific diphenylmethylene(cyclopentadienyl)(9-fluorenyl)zirconium dichloride (4) with methylaluminoxane as a cocatalyst. Isospecific zirconocene catalysts 1-3 produced copolymers having narrow molecular weight distribution, while syndiospecific catalyst 4 effected propylene homopolymerization. Microstructures of the copolymers were studied by 13C NMR and distortionless enhancement of polarization transfer (DEPT) spectroscopy. CPE was found to be incorporated in the copolymer preferentially via 1,2-insertion mechanism in the copolymerization with the catalyst 3. The catalyst 1 and 2 gave copolymers containing CPE units formed by either 1,2-insertion or 1,3-insertion mechanism. The proportion of 1,3-insertion units increased with increasing CPE content in the copolymers. The isomerization reaction from 1,2-insertion to 1,3-insertion CPE units was discussed on the basis of kinetic parameters.  相似文献   

3.
Naofumi Naga  Akinori Toyota 《Polymer》2004,45(22):7513-7517
Copolymerization of ethylene and 2-vinylnaphtalene (VN) has been investigated with dimethylsilylene(tetramethylcyclopentadienyl)(N-tert-butyl)titanium dichloride (1) and rac-isopropylidenebis(indenyl)zirconium dichloride (2) using methylaluminoxane as a cocatalyst. The copolymerization gave the corresponding copolymer in good yield. The catalyst 1 showed higher incorporation of VN than the catalyst 2. Thermal properties of the resulting copolymers were investigated by DSC in comparison with those of poly(ethylene-co-styrene), and poly(ethylene-co-VN) showed higher Tg than poly(ethylene-co-styrene).  相似文献   

4.
Treatment of a dihydrosilane (methylphenylsilane, 1) with mixtures of a diyne (p- or m-diethynylbenzene, 2a or 2b) and a triyne (1,3,5-triethynylbenzene, 3a or B,B′,B″-triethynyl-N,N′,N″-trimethylborazine, 3b; 1:2:3=100:95:5, 100:90:10, 100:80:20) in the presence of Pd-PCy3 (Cy=cyclohexyl) catalyst gave new crosslinked silylenedivinylene polycarbosilanes. In TGA the resulting crosslinked polymers tended to show higher Td5 values and higher char yields than the corresponding linear polymers. On the other hand, UV/vis absorption spectra of the crosslinked polymers obtained in the reactions of 2a or 2b with 3a exhibited increased broad peaks around 390 nm for 2a or 360 nm for 2b. Coincidently, their fluorescence spectra showed significant increase of the emission peaks in 400-550 nm. The crosslinked polymer derived from 2a and 3b, however, showed decrease of the absorption peak around 390 nm and profound depression of fluorescence peaks in 400-550 nm.  相似文献   

5.
Toru Katsumata 《Polymer》2008,49(12):2808-2816
The polymerization of diphenylacetylene derivatives possessing tert-amine moieties, such as triphenylamine, N-substituted carbazole and indole, was examined in the presence of TaCl5-n-Bu4Sn (1:2) catalyst. A polymer with high molecular weight (Mw = 570 × 103) was obtained in good yield by the polymerization of diphenylamine-containing monomer 1b, whereas the isopropylphenylamine derivative (1c) gave a polymer with relatively low molecular weight (Mw = 2.4 × 103). The polymerization of monomer 1d containing cyclohexylphenylamine group did not proceed; however, carbazolyl- and indolyl-containing monomers also produced polymers. Poly(1b), poly(2f) and poly(4b) could be fabricated into free-standing membranes by casting toluene solutions of these polymers. The gas permeability of poly(1b) was too low to be evaluated accurately whereas poly(4b) possessing two chlorine atoms in the repeating unit showed higher gas permeability than that of poly(1b); furthermore, poly(2f) having trimethylsilyl and 3-methylindolyl groups exhibited relatively high gas permeability (). In the cyclic voltammograms of diphenylamino group-containing polymers, poly(1b) and poly(2b), the intensities of oxidation and reduction peaks decreased more than those of carbazolyl-containing poly(2a). The molar absorptivity (?) of poly(1b) at ∼700 nm increased with increasing applied voltage in the UV-vis spectrum.  相似文献   

6.
The electrochemical study of N-tert-butoxy-2,4-diphenyl-6-tert-butylphenylaminyl (1a), N-tert-butoxy-2,4-bis(4-chlorophenyl)-6-tert-butylphenylaminyl (1b), N-[2-(methoxycarbonyl)-2-propyl]-2,4-diphenyl-6-tert-butylphenylaminyl (2), and N-tert-butoxy-2,4,6-tris(4-chlorophenyl)phenylaminyl radicals (3) was performed by cyclic voltammetry using acetonitrile as the solvent and Bu4NPF6 as the supporting electrolyte. On cathodic scan (100 mV/s), all the radicals gave chemically reversible cyclic voltammograms, and the were determined to be −1.405 V (1a), −1.310 V (2a), −1.282 V (2b), and −1.195 V (3) (versus Fc+/Fc), respectively. On anodic scan (100 mV/s), on the other hand, 1a, 1b and 2 showed chemically reversible cyclic voltammograms, but 3 exhibited a partially reversible couple even on a scan rate of 500 mV/s, indicating that the cation species of 3 was less stable. The determined for 1a, 1b, 2 and 3 were 0.220, 0.280, 0.318 and 0.294 V (versus Fc+/Fc), respectively. The electrochemical data were compared with those of thioaminyl radicals, the corresponding sulfur analogues of 1-3.  相似文献   

7.
A series of new titanium isopropoxide complexes (1-4-Ti(OiPr)2 based on enantiopure (1-H2), racemic (2-H2), meso (3-H2) and diastereomeric (4-H2) aminodiol ligands have been prepared and tested as initiators for the ring opening polymerization (ROP) of l/rac-lactide in solution and in bulk conditions. All complexes were shown to have significant activity in solution at 70 °C and higher activity in bulk at 130 °C with a good control over the molar mass distribution and molecular weights. The complex derived from the racemic-aminodiol ligand gave partially heterotactic polylactide in ROP of rac-lactide and afforded atactic polylactide in the bulk, whereas all other complexes yielded atactic polylactides both in solution and in bulk. Ligand variation (chirality) in the complexes has little effect on either the activity or selectivity of the initiators. The polymerization kinetics using (1-Ti(OiPr)2) as an initiator indicated a first order reaction with respect to the monomer concentration.  相似文献   

8.
João Carlos Ramos 《Polymer》2006,47(24):8095-8100
(R)-(−) (1) and (S)-(+)-2-(3′-Thienyl)ethyl N-(3″,5″-dinitrobenzoyl)-α-phenylglycinate (2) monomers were synthesized, characterized, and polymerized in chloroform using FeCl3 as an oxidizing agent. Molecular weights of 2.6 × 104 and 3.2 × 104 for poly1 and poly2, respectively, were determined by SEC analysis. FTIR spectra of the polymers indicated the coupling of monomers through the α positions. UV-vis spectra showed absorption bands at λmax = 226 and 423 nm for poly1 and poly2, ascribed to transitions of side groups and polythiophene backbone, respectively. Poly1 and poly2 remained stable up to 210 °C. At higher temperatures, a two step weight loss degradation process was observed for both polymers by TGA analysis. 1H NMR, in the presence of Eu(tfc)3, and optical rotation measurements indicate the chiral properties of the monomers 1 ([α]D28 = −76.2) and 2 ([α]D28 = +76.0), and the maintenance of chirality after polymerization (poly1 [α]D28 = −29.0 and poly2 [α]D28 = +28.4, c = 2.5 in THF). According to scanning electron microscopic analysis, the polymers are highly porous.  相似文献   

9.
Synthesis and properties of helical polyacetylenes containing carbazole   总被引:1,自引:0,他引:1  
Jinqing Qu  Toshio Masuda 《Polymer》2007,48(2):467-476
Novel acetylene monomers containing carbazole with chiral menthyl and bornyl groups, 9-(1R,2S,5R)-menthyloxycarbonyl-2-ethynylcarbazole (1), 9-(1S,2R,5S)-menthyloxycarbonyl-2-ethynylcarbazole (2), 9-(1R,2S,5R)-menthyloxycarbonyl-3-ethynylcarbazole (3) and 9-(1S)-bornyloxycarbonyl-2-ethynylcarbazole (4) were synthesized and polymerized with a Rh catalyst to give the corresponding polymers [poly(1)-poly(4)] with moderate Mn value of (11.5-92.2) × 103 in good yields (77-89%). CD spectroscopic studies revealed that poly(1), poly(2) and poly(4) took predominantly one-handed helical structure in CHCl3, THF, toluene, and CH2Cl2, while poly(3) did not. Addition of methanol to CHCl3 solutions of poly(1) and poly(2) resulted in the formation of aggregates showing smaller CD signals at 275 and 320 nm. The helical structure of poly(1) and poly(2) was very stable against heating. The polymers emitted fluorescence in 0.40-2.90% quantum yields. Poly(4) exhibited an obvious oxidation peak at 1.10 V. The polymers were thermally stable below 300 °C.  相似文献   

10.
Jinqing Qu  Toshio Masuda 《Polymer》2007,48(16):4628-4636
Novel chiral acetylene monomers bearing carbazole and triphenylamine groups, namely, (S)-3-butyn-2-yl 2-(9-carbazolyl)ethyl carbonate (1) and (S)-3-butyn-2-yl 4-(diphenylamino)benzoate (2) were synthesized, and polymerized with Rh+(nbd)[η6-C6H5B(C6H5)3] catalyst to give the corresponding polymers with moderate molecular weights (Mn 13.0 × 103 and 15.5 × 103) in good yields (86% and 88%). CD spectroscopic studies revealed that poly(1) and poly(2) took predominantly one-handed helical structure in CHCl3. The helical structures of poly(1) and poly(2) were very stable against heating and addition of MeOH. The solution of poly(1) and poly(2) emitted fluorescence in 0.52% and 7.2% quantum yields, which were lower than those of the corresponding monomers 1 and 2 (22.5% and 76.5%). The cyclic voltammograms of the polymers indicated that the oxidation potentials of the polymers were lower than those of the monomers. The polymers showed electrochromism and changed the color from pale yellow to pale blue by application of voltage, presumably caused by the formation of polaron at the carbazole and triphenylamine moieties. The onset temperatures of weight loss of poly(1) and poly(2) were 225 and 270 °C under air.  相似文献   

11.
A series of phosphoryl (PO) contained compounds: triethylphosphate (a), diethylphenylphosphate (b), ethyldiphenylphosphate (c) triarylphosphates (d and h-m), triphenylphosphine oxide (e), phenyl diphenylphosphinate (f) and diphenyl phenylphosphonate (g) have been prepared. Iron catalysts, which are generated in situ by mixing the compounds with Fe(2-EHA)3 and AliBu3 in hexane, are tested for butadiene polymerization at 50 °C. Phosphates donated catalysts have been, unprecedently, found to conduct extremely high syndiotactically (pentad, rrrr = 46.1-94.5%) enriched 1,2-selective (1,2-structure content = 56.2-94.3%) polymerization of butadiene. Introduction of electron withdrawing substituents on phenyl rings oftriphenylphosphate (k-m) remarkably promotes catalytic activity, while bulky substituent isopropyl at 2-position (h) has beneficial influence on regioselectivity. Employment of e, f or g as donor, results in a suppressed monomer conversion, accompanied by deteriorated 1,2-regioselectivity. The effects of polymerization conditions such as reaction temperature, types of cocatalysts and polymerization medium are also investigated by using catalyst system with tri(2,4-difluorophenyl)phosphate (m) as donor. Highly tolerance to polymerization temperature up to 80 °C is observed for the first time in the iron-based catalyst.  相似文献   

12.
A series of novel amphiphilic fluorescent CBABC-type pentablock copolymers (Py-PMMA-PEG4600-PMMA-Py) were prepared from BAB-type amphiphilic triblock copolymer (PMMA-PEG4600-PMMA) as macroinitiator with various contents of 1-(methacryloyloxyethylamino-carboxylmethyl) pyrene (PyMOI) by atom transfer radical polymerization (ATRP) in toluene using CuBr/2,2-bipyridine as catalyst system. Triblock copolymer (PMMA-PEG4600-PMMA) was prepared by ATRP and obtained from Br-PEG4600-Br as macroinitiator with methyl methacrylate in tetrahydrofuran using the same catalyst. The molecular weights of pentablock copolymers which were reinitiated by PMMA-PEG4600-PMMA macroinitiator were calculated from 1H NMR spectra up to 42,400 gmol−1. The polydispersity of pentablock copolymers obtained from GPC analysis was narrow between 1.10 and 1.38. The crystallinity of triblock copolymer (PMMA-PEG4600-PMMA) was decreased slightly with incorporating PMMA segment. Introducing the bulky pyrene substituent into pentablock copolymer, the melting temperature was not observed and all pentablock copolymers showed amorphous patterns in wide-angle X-ray scattering (WAXS) due to decrease in the degree of crystallinity of polymer chain because of disturbing regular packing. The temperatures at 10% weight loss (Td10), examined by TG analysis, showed values ranging from 265 to 323 °C in nitrogen and 264 to 313 °C in air. Fluorescence spectra of Py-PMMA-PEG4600-PMMA-Py exhibited stronger excimer emission at ca. 480 nm due to the aggregations of pyrene group formed via interaction of the hydrophobic chains. The more content of PyMOI segment in pentablock copolymers can obtain the higher emission intensity ca. 480 nm. When there were higher PyMOI contents (84.9 wt% PyMOI) in pentablock copolymers, they formed larger aggregates (210 nm) in SEM micrographs. On the other hand, while increasing the concentration of the polymer solution in THF, the morphology was changed from spherical (0.1 mg/mL) to chainlike (1.0 mg/mL) aggregates.  相似文献   

13.
Jianguo Ni 《Polymer》2008,49(1):211-216
Norbornene polymerization and ethylene/norbornene copolymerization were studied using constrained geometry complexes 2-(tetramethylcyclopentadienyl)-4,6-di-tert-butylphenoxytitanium dichloride (1), 2-(tetramethylcyclopentadienyl)-6-tert-butylphenoxytitanium dichloride (2), and 2-(tetramethylcyclopentadienyl)-6-phenylphenoxytitanium dichloride (3) as catalysts with AliBu3 and Ph3CB(C6F5)4 as cocatalysts. Polymerization results indicate that these catalyst systems are highly active for both the homopolymerization of norbornene and the copolymerization of ethylene with norbornene. The norbornene homopolymerization is vinyl addition polymerization. Ethylene/norbornene copolymers with high norbornene incorporation (>50%) were easily obtained with these catalyst systems by increasing the norbornene feed concentration. The produced polymers were characterized by 13C NMR, IR, DSC and GPC.  相似文献   

14.
Linear polyethylene/branched polyethylene blends (LPE/BPE) were prepared using the homogeneous binary catalyst system composed by Ni(α-diimine)Cl2 (1) (α-diimine=1,4-bis(2,6-diisopropylphenyl)-acenaphthenediimine) and rac-ethylenebis(IndH4)ZrCl2 (2) (IndH4=4,5,6,7-tetrahydro-1-η5-indenyl) activated with methylaluminoxane in hexane at three different polymerization temperatures (0, 30 and 50 °C) and by varying the zirconium loading molar fraction (xZr). The polymerization runs carried out at 30 °C have shown that the productivity decreases linearly with xZr. On the other hand, at 0 and 50 °C, a non-linear dependence was observed between the xZr and the productivity. The molecular weight of the LPE/BPE blends varied from 222 to 470×103 g mol−1 with polydispersities around 2.0. Differential scanning calorimetry results showed that the dependence of the Tm values with respect to the xZr it is higher for the LPE/BPE blends produced at 0 °C. Dynamic mechanical thermal analysis shows the formation of different polymeric materials where the stiffness varies according to the xZr. The surface morphology of the BPE/HDPE blends produced at 30 °C revealed a low miscibility between the PE phases resulting in the formation of a ‘cobweb structure’ (for xZr=0.25) after etched with hot o-xylene.  相似文献   

15.
Yuushou Nakayama  Kenta Sasaki 《Polymer》2009,50(20):4788-2103
Catalytic behavior of tetrahydroborate complexes of rare earth metals, Ln(BH4)3(THF)x (1: Ln = La, x = 3; 2: Ln = Pr, x = 2; 3: Ln = Nd, x = 3; 4: Ln = Sm, x = 3; 5: Ln = Y, x = 2.5; 6: Ln = Yb, x = 3), for ring-opening polymerization (ROP) of six-membered cyclic esters, δ-valerolactone (VL) and d,l-lactide (d,l-LA), was studied. The controlled polymerization of VL with 1-6 proceeded in THF at 60 °C. The catalytic activities of these complexes for the ROP of VL were observed to be in order of the ionic radii of the metals: 1(La) ≥ 2(Pr) ≥ 3(Nd) > 4(Sm) > 5(Y) > 6(Yb). The obtained polymers were demonstrated to be hydroxy-telechelic by 1H NMR and MALDI-TOF MS spectroscopy. The controlled ROP of d,l-LA also proceeded by these complexes. The activities of these complexes for the d,l-LA ROP were also in order of the ionic radii of the metals.  相似文献   

16.
The electrochemical properties of a series of cyclic arylboronic esters, XC6H4B(OR)2 [RR = CH2CH2; X = H (1a); p-Me (1b); p-OMe (1c); p-Cl (1d); p-Ph (1e); m-Cl (1f); m-OMe (1g); CF3 (1h); OMe (1i); 2,6-dimethyl (1j); 1b with RR = (CH2)3, (1k); 1b with RR = CMe2CMe2, (1m)] has been studied in acetonitrile by cyclic voltammetry (CV) and controlled-potential electrolysis (CPE). The CV of representative examples of aryl borates with different substituents show one irreversible oxidation wave on a Pt cathode, at 1.8-1.9 V (vs. Ag/AgCl), with a negligible substituent effect. The cathodic CPE process led to small amounts of biaryls only, whereas the direct anodic CPE could not be carried out practically due to low currents. However, in the presence of electrogenerated bromonium (or iodonium) ions a C-B bond cleavage does take place to yield the corresponding bromoaryls, brominated phenols, and arylboronic acids as the major products.  相似文献   

17.
Akito Fukui 《Polymer》2009,50(17):4159-5967
Diarylacetylenes having fluorenyl groups and other substituents (trimethylsilyl, t-butyl, bromine, fluorine) (1a-1) were polymerized with TaCl5-n-Bu4Sn. Monomers 1a-l produced high molecular weight polymers 2a-l (Mw 5.1 × 105-1.3 × 106) in 12-59% yields. All of the polymers were soluble in common organic solvents, and gave tough free-standing membranes by the solution casting method. The onset temperatures of weight loss of polymers 2a-l in air were over 400 °C, indicating considerably high thermal stability. All the polymer membranes showed high gas permeability; e.g., the oxygen permeability coefficient (PO2) of 2a was as large as 4800 barrers. Membrane 2d possessing two fluorine atoms at meta and para positions of the phenyl ring showed the highest oxygen permeability (PO2 = 6600 barrers) among the present polymers.  相似文献   

18.
Jinqing Qu  Toshio Masuda 《Polymer》2006,47(19):6551-6559
Novel acetylene monomers containing N-phenyl-substituted carbazole (Cz) and triphenylamine (TPA) groups, namely, 3-ethynyl-9-phenylcarbazole (1) and p-(N,N-diphenylamino)phenylacetylene (2) were synthesized, and polymerized with several Rh-, W-, and Mo-based catalysts. Poly(1) and poly(2) with high number-average molecular weights (15?500-974?000) were obtained in good yields (77-97%), when [(nbd)RhCl]2-Et3N (nbd = norbornadiene) was used as a catalyst. The polymers exhibited UV-vis absorption peaks derived from the Cz and TPA moieties at 250-350 nm and polyacetylene backbone above 350 nm. The UV-vis absorption band edge wavelengths of the polymers were longer than those of the corresponding monomers. Poly(2) exhibited a UV-vis absorption peak at a longer wavelength than poly(1) did, which indicates that poly(2) has main chain conjugation longer than that of poly(1). The molecular weights and photoluminescence quantum yields of the polymers obtained by the polymerization using [(nbd)RhCl]2-Et3N were larger than those of the Rh+(nbd)[η6-C6H5B(C6H5)3]-based counterparts. The cyclic voltammograms of the polymers indicated that they had clear electrochemical properties; the onset oxidation voltage of poly(1) was higher than those of N-alkyl-substituted Cz derivatives. The polymers showed electrochromism and changed the color from pale yellow to blue by application of voltage, presumably caused by the formation of charged polaron at the Cz and TPA moieties. The temperatures for 5% weight loss of the polymers were around 350-420 °C under air, indicating the high thermal stability.  相似文献   

19.
A new synthetic method for the preparation of poly(benzoxazole) (PBO) precursor, poly(o-hydroxyamide) (7) from bis(o-aminophenol) (5) and diphenyl isophthalate (6) has been developed. Polymer 7 was prepared by the polycondensation of 5 and 6 in 1-methyl-2-pyrrolidinone (NMP) at 185-205 °C. Model reactions were carried out in detail to elucidate appropriate conditions for the formation of 2-hydroxybenzanilide (3) from o-aminophenol (1) and phenyl benzoate (2). The photosensitive (PBO) precursor based on polymer 7 containing a 22% of benzoxazole unit and 30 wt% 1-{1,1-bis[4-(2-diazo-1-(2H)naphthalenone-5-sulfonyloxy)phenyl]ethyl}-4-{1-[4-(2-diazo-1(2H)naphthalenone-5-sulfonyloxy)phenyl]methylethyl}benzene (S-DNQ) showed a sensitivity of 110 mJ cm−2 and a contrast of 5.0 when it was exposed to 436 nm light followed by developing with a 2.38 wt% aqueous tetramethylammonium hydroxide solution at room temperature. A fine positive image featuring 8 μm line and space patterns was observed on the film of the photoresist exposed to 200 mJ cm−2 of UV-light at 436 nm by the contact mode.  相似文献   

20.
Chien-An Chen 《Polymer》2008,49(6):1512-1519
Two novel cross-linked polystyrene-supported N-sulfonylated β-aminoalcohol resins 13 and 14 have been prepared from radical co-polymerizations of styrene, divinylbenzene, and styrenes bearing a para-substituent of N-sulfonylated aminoalcohol. Resins 13 and 14 were obtained in high yields of 85.8 and 84.7%, and were characterized by IR and solid state 13C NMR spectroscopies. Elemental analyses reveal that 1 g of resin 13 contains 0.93 mmol bidentate N-sulfonylated β-aminoalcohol. The ligand content in tridentate resin 14 is calculated to be 0.95 mmol/g. The Ti(O-i-Pr)4/13 catalytic system works excellently in asymmetric ZnEt2 additions to aldehydes affording secondary alcohols in ≥90% ee. Resin 13 can be reused 9 times without losing any activity, giving the product with enantioselectivities ≥87% ee. The Ti(O-i-Pr)4/14 system was used only once in asymmetric AlEt3 additions to a variety of aldehydes affording secondary alcohols in good to excellent enantioselectivities from 73 to 92% ee.  相似文献   

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