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1.
Two novel phenyl‐substituted poly(p‐phenylene vinylene) derivatives, poly{2‐[3′,4′‐(2″‐ethylhexyloxy)(3″,7″‐dimethyloctyloxy)benzene]‐1,4‐phenylenevinylene} (EDP‐PPV) and poly{2‐[3′,4′‐(2″‐ethylhexyloxy)(3″,7″‐dimethyloctyloxy)benzene]‐5‐methoxy‐1,4‐phenylenevinylene} (EDMP‐PPV), and their copolymer, poly{2‐[3′,4′‐(2″‐ethylhexyloxy)(3″,7″‐dimethyloctyloxy)benzene]‐1,4‐phenylene‐vinylene‐co‐2‐[3′,4′‐(2″‐ethylhexyloxy)(3″,7″‐dimethyloctyloxy)benzene]‐5‐methoxy‐1,4‐phenylenevinylene} (EDP‐co‐EDMP‐PPV; 4:1, 1:1, and 1:4), were successfully synthesized according to the Gilch route. The structures and properties of the monomers and the resulting conjugated polymers were characterized with 1H‐NMR, 13C‐NMR, elemental analysis, gel permeation chromatography, thermogravimetric analysis, ultraviolet–visible absorption spectroscopy, and photoluminescence and electroluminescence (EL) spectroscopy. The EL polymers possessed excellent solubility in common solvents and good thermal stability with a 5% weight loss temperature of more than 380°C. The weight‐average molecular weights and polydispersity indices of EDP‐PPV, EDMP‐PPV, and EDP‐co‐EDMP‐PPV were 1.40–2.58 × 105, and 1.19–1.52, respectively. Double‐layer light‐emitting diodes with the configuration of indium tin oxide/polymer/tris(8‐hydroxyquinoline)aluminum/Al devices were fabricated, and EDP‐co‐EDMP‐PPV (1:1) showed the highest EL performance and exhibited a maximum luminance of 1050 cd/m2 at 19.5 V. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 1259–1266, 2005  相似文献   

2.
The radical‐initiated terpolymerization of 3,4‐dihydro‐2H‐pyran (DHP), maleic anhydride (MA), and vinyl acetate (VA), which were used as a donor–acceptor–donor system, was carried out in methyl ethyl ketone in the presence of 2,2′‐azobisisobutyronitrile as an initiator at 65°C in a nitrogen atmosphere. The synthesis and characterization of binary and ternary copolymers, some kinetic parameters of terpolymerization, the terpolymer‐composition/thermal‐behavior relationship, and the antitumor activity of the synthesized polymers were examined. The polymerization of the DHP–MA–VA monomer system predominantly proceeded by the alternating terpolymerization mechanism. The in vitro cytotoxicities of poly(3,4‐dihydro‐2H‐pyran‐alt‐maleic anhydride) [poly(DHP‐alt‐MA)] and poly(3,4‐dihydro‐2H‐pyran‐co‐maleic anhydride‐co‐vinyl acetate) [poly(DHP‐co‐MA‐co‐VA)] were evaluated with Raji cells (human Burkitt lymphoma cell line). The antitumor activity of the prepared anion‐active poly(DHP‐alt‐MA) and poly(DHP‐co‐MA‐co‐VA) polymers were studied with methyl–thiazol–tetrazolium testing, and the 50% cytotoxic dose was calculated. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 2352–2359, 2005  相似文献   

3.
Metal‐chelating membranes have advantages as adsorbents in comparison with conventional beads because they are not compressible and they eliminate internal diffusion limitations. The aim of this study was to explore in detail the performance of poly(2‐hydroxyethyl methacrylate–methacryloylamidohistidine) [poly(HEMA–MAH)] membranes for the removal of three toxic heavy‐metal ions—Cd(II), Pb(II), and Hg(II)—from aquatic systems. The poly(HEMA–MAH) membranes were characterized with scanning electron microscopy and 1H‐NMR spectroscopy. The adsorption capacity of the poly(HEMA–MAH) membranes for the selected heavy‐metal ions from aqueous media containing different amounts of these ions (30–500 mg/L) and at different pH values (3.0–7.0) was investigated. The adsorption capacity of the membranes increased with time during the first 60 min and then leveled off toward the equilibrium adsorption. The maximum amounts of the heavy‐metal ions adsorbed were 8.2, 31.5, and 23.2 mg/g for Cd(II), Pb(II), and Hg(II), respectively. The competitive adsorption of the metal ions was also studied. When the metal ions competed, the adsorbed amounts were 2.9 mg of Cd(II)/g, 14.8 mg of Pb(II)/g, and 9.4 mg of Hg(II)/g. The poly(HEMA–MAH) membranes could be regenerated via washing with a solution of nitric acid (0.01M). The desorption ratio was as high as 97%. These membranes were suitable for repeated use for more than three adsorption/desorption cycles with negligible loss in the adsorption capacity. The stability constants for the metal‐ion/2‐methacryloylamidohistidine complexes were calculated to be 3.47 × 106, 7.75 × 107, and 2.01 × 107 L/mol for Cd(II), Pb(II), and Hg(II) ions, respectively, with the Ruzic method. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 1213–1219, 2005  相似文献   

4.
A novel polymer (poly[2,2'‐(4,4'‐bithiazolylene)][N‐(2‐ethylhexyl)‐3,6‐carbazylene] (PBTCA) was first synthesized from 2,2′‐diamino‐4,4′‐bithiazole and N‐(2‐ethylhexyl)‐3,6‐diformylcarbazole. The structure of the polymer was determined with IR and 1H‐NMR spectroscopy. The PBTCA–Nd3+ complex was prepared via the mixing of neodymium trichloride hexahydrate and PBTCA in dimethyl sulfoxide under a nitrogen atmosphere. The magnetic behaviors of the Nd3+ complex of a poly(Schiff base) were measured as a function of the magnetic field strength (0–50 kOe) at 4 K and as a function of the temperature (4–300 K). The results show that PBTCA–Nd3+ is a ferromagnet when the temperature is below 15 K, and above that, it is a diamagnet. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 443–446, 2006  相似文献   

5.
New π‐conjugated polymers containing dithieno(3,2‐b:2′,3′‐d)pyrrole (DTP) were successfully synthesized via electropolymerization. The effect of structural differences on the electrochemical and optoelectronic properties of the 4‐[4H‐dithieno(3,2‐b:2′,3′‐d)pyrrol‐4‐yl]aniline (DTP–aryl–NH2), 10‐[4H‐dithiyeno(3,2‐b:2′,3′‐d)pirol‐4‐il]dekan‐1‐amine (DTP–alkyl–NH2), and 1,10‐bis[4H‐dithieno(3,2‐b:2′,3′‐d)pyrrol‐4‐yl] decane (DTP–alkyl–DTP) were investigated. The corresponding polymers were characterized by cyclic voltammetry, NMR (1H‐NMR and 13C‐NMR), and ultraviolet–visible spectroscopy. Changes in the electronic nature of the functional groups led to variations in the electrochemical properties of the π‐conjugated systems. The electroactive polymer films revealed redox couples and exhibited electrochromic behavior. The replacement of the DTP–alkyl–DTP unit with DTP–aryl–NH2 and DTP–alkyl–NH2 resulted in a lower oxidation potential. Both the poly(10‐(4H‐Dithiyeno[3,2‐b:2′,3′‐d]pirol‐4‐il)dekan‐1‐amin) (poly(DTP–alkyl–NH2)) and poly(1,10‐bis(4H‐dithieno[3,2‐b:2′,3′‐d]pyrrol‐4‐yl) decane) (poly(DTP–alkyl–DTP)) films showed multicolor electrochromism and also fast switching times (<1 s) in the visible and near infrared regions. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40701.  相似文献   

6.
The aim of this study was to prepare magnetic beads that could be used for the removal of heavy‐metal ions from synthetic solutions. Magnetic poly(ethylene glycol dimethacrylate–1‐vinyl‐1,2,4‐triazole) [m‐poly(EGDMA–VTAZ)] beads were produced by suspension polymerization in the presence of a magnetite Fe3O4 nanopowder. The specific surface area of the m‐poly(EGDMA–VTAZ) beads was 74.8 m2/g with a diameter range of 150–200 μm, and the swelling ratio was 84%. The average Fe3O4 content of the resulting m‐poly(EGDMA–VTAZ) beads was 14.8%. The maximum binding capacities of the m‐poly(EGDMA–VTAZ) beads from aquous solution were 284.3 mg/g for Hg2+, 193.8 mg/g for Pb2+, 151.5 mg/g for Cu2+, 128.1 mg/g for Cd2+, and 99.4 mg/g for Zn2+. The affinity order on a mass basis was Hg2+ > Pb2+ > Cu2+ > Cd2+> Zn2+. The binding capacities from synthetic waste water were 178.1 mg/g for Hg2+, 132.4 mg/g for Pb2+, 83.5 mg/g for Cu2+, 54.1 mg/g for Cd2+, and 32.4 mg/g for Zn2+. The magnetic beads could be regenerated (up to ca. 97%) by a treatment with 0.1M HNO3. These features make m‐poly(EGDMA–VTAZ) beads potential supports for heavy‐metal removal under a magnetic field. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009  相似文献   

7.
Antimicrobial characteristics were investigated for norfloxacin against 18 bacteria (4 gram‐positive bacteria and 14 gram‐negative bacteria) with the minimum inhibition concentration (MIC) test. Among the bacteria tested, B. cereus, V. fluvialis, and V. parahaemolyticus formed norfloxacin‐tolerant colonies. The release of ultraviolet‐absorbing substances from the cells in contact with norfloxacin was examined for the native bacteria and for the norfloxacin‐tolerance‐induced ones. Norfloxacin was grafted to polypropylene‐graft‐maleic anhydride (MAPP) and poly(styrene‐co‐maleic anhydride) (MAPS) to synthesize polymeric antimicrobial agents. The bioactivity of MAPP–norfloxacin and MAPS–norfloxacin was evaluated and compared with that of neat norfloxacin with the shake flask test and the MIC test. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 936–943, 2005  相似文献   

8.
A comparative study of pH‐responsive polyzwitterions (PZs) with polyampholyte or polybetaine architectures was conducted with well‐defined model polymer systems. Low‐charge‐density PZs, including ampholytic terpolymers composed of acrylamide (AM), sodium 3‐acrylamido‐3‐methylbutanoate, and (3‐acrylamidopropyl)trimethylammonium chloride and carboxybetaine copolymers composed of AM and 3‐(3‐acrylamidopropyldimethylammonio)propionate, were prepared via free‐radical polymerization in 0.5M NaCl to yield ter‐ and copolymers with random termonomer and comonomer distributions. Sodium formate was used as a chain‐transfer agent during the polymerizations to eliminate the effects of the monomer feed composition on the degree of polymerization (DP) and to suppress gel effects and broadening of the molecular weight distributions. The polymer compositions were determined via 13C‐NMR spectroscopy, and the residual counterion content was determined via elemental analysis for Na+ and Cl?. The molecular weights (MWs) and polydispersity indices (PDIs) were determined via size exclusion chromatography/multi‐angle laser light scattering (SEC–MALLS); the polymer MWs ranged from 1.4 to 1.5 × 106 g/mol, corresponding to DPs of 1.6–1.9 × 104 repeat units, with all the polymers exhibiting PDIs less than or equal to 2.1. The intrinsic viscosities determined from SEC–MALLS data and the Flory–Fox relationship agreed with the intrinsic viscosities determined via low‐shear dilute‐solution viscometry. Data from the SEC–MALLS analysis were used to analyze the radius of gyration/molecular weight (RgM) relationships and the Mark–Houwink–Sakurada intrinsic viscosity/molecular weight ([η]–M) relationships for the PZs. The RgM and [η]–M relationships and viscometric data revealed that under size exclusion chromatography conditions, the poly[acrylamide‐co‐3‐(3‐acrylamidopropyldimethylammonio)propionate] betaine copolymers had more open, random‐coil conformations and greater polymer–solvent interactions than the ampholytic poly[acrylamide‐co‐sodium 3‐acrylamido‐3‐methylbutanoate‐co‐(3‐acrylamidopropyl)trimethylammonium chloride] terpolymers. The pH‐ and salt‐responsive dilute‐solution viscosity behavior of the PZs was examined to assess the effects of the polymer structure and composition on the solution properties. The polyampholyte terpolymers had greater solution viscosities and more pronounced stimuli‐responsiveness than the polybetaine copolymers because of their stronger intramolecular interactions and increased chain stiffness. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 24–39, 2004  相似文献   

9.
Polyaniline (PANI), poly(o‐anisidine), and poly[aniline‐co‐(o‐anisidine)] were synthesized by chemical oxidative polymerization with ammonium persulfate as an oxidizing reagent in an HCl medium. The viscosities, electrical conductivity, and crystallinity of the resulting polymers (self‐doped forms) were compared with those of the doped and undoped forms. The self‐doped, doped, and undoped forms of these polymers were characterized with infrared spectroscopy, ultraviolet–visible spectroscopy, and a four‐point‐probe conductivity method. X‐ray diffraction characterization revealed the crystalline nature of the polymers. The observed decrease in the conductivity of the copolymer and poly(o‐anisidine) with respect to PANI was attributed to the incorporation of the methoxy moieties into the PANI chain. The homopolymers attained conductivity in the range of 3.97 × 10?3 to 7.8 S/cm after doping with HCl. The conductivity of the undoped forms of the poly[aniline‐co‐(o‐anisidine)] and poly(o‐anisidine) was observed to be lower than 10?5 J/S cm?1. The conductivity of the studied polymer forms decreased by the doping process in the following order: self‐doped → doped → undoped. The conductivity of the studied polymers decreased by the monomer species in the following order: PANI → poly[aniline‐co‐(o‐anisidine)] → poly(o‐anisidine). All the polymer samples were largely amorphous, but with the attachment of the pendant groups of anisidine to the polymer system, the crystallinity region increased. The undoped form of poly[aniline‐co‐(o‐anisidine)] had good solubility in common organic solvents, whereas doped poly[aniline‐co‐(o‐anisidine)] was moderately crystalline and exhibited higher conductivity than the anisidine homopolymer. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci, 2006  相似文献   

10.
Two diamine monomers, 4‐[4‐(1‐methyl‐1‐phenylethyl)phenoxy]‐1,3‐diamino benzene and 4‐{4‐[(4‐methylphenyl)sulfonyl]phenoxy}‐1,3‐diamino benzene, were synthesized, and both diamines were polycondensed with three commercial dianhydrides to obtain aromatic polyimides containing pendant groups. The polyimides were characterized by solubility tests, viscosity measurements, IR, 1H‐NMR, and 13C‐NMR spectroscopy, X‐ray diffraction studies, and thermogravimetric analysis. The polyimides had inherent viscosities of 0.33–0.58 dL/g in m‐cresol at 30 ± 0.1°C. All the polyimides were amorphous and were soluble in solvents such as N,N‐dimethylacetamide, N‐methyl‐2‐pyrrolidone, N,N‐dimethylformamide, and m‐cresol. Thermogravimetric analysis of the polyimides indicated no weight loss below 410°C under a nitrogen atmosphere. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 1377–1384, 2005  相似文献   

11.
A new diol with a one‐sided azobenzene‐carboxyl group was prepared to be used for photosensible polymers synthesis. Azobenzene carboxyl containing polyurethane based on poly(tetramethylene oxide) diol of 2000 average molecular weight, 2,4‐tolylene diisocyanate, and the mentioned azo diol, was obtained and characterized. Upon neutralization the acid form with metal acetate (Li+1, Ca+2) or triethylamine azo carboxylate anionomers with an improved phase separation were obtained. Viscometric measurements of diluted dimethylformamide solutions exhibited evidence of polyelectrolyte behavior. Some aspects of the trans‐cis photoisomerization have been examined to design in future various dyed aqueous dispersions. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 577–582, 2005  相似文献   

12.
A copolymer of dendronized poly(p‐phenylene vinylene) (PPV), poly{2‐[3′,5′‐bis (2′‐ethylhexyloxy) bnenzyloxy]‐1,4‐phenylene vinylene}‐co‐poly[2‐methoxy‐5‐(2′‐ethylhexyloxy)‐1,4‐phenylene vinylene] (BE‐co‐MEH–PPV), was synthesized with the Gilch route to improve the electroluminescence and photovoltaic properties of the dendronized PPV homopolymer. The polymer was characterized by ultraviolet–visible absorption spectroscopy, photoluminescence spectroscopy, and electrochemical cyclic voltammetry and compared with the homopolymers poly{2‐[3′, 5′‐bis(2‐ethylhexyloxy) benzyloxy‐1,4‐phenylene vinylene} (BE–PPV) and poly[2‐methoxy‐5‐(2′‐ethylhexyloxy)‐1,4‐phenylenevinylene] (MEH–PPV). Polymer light‐emitting diodes based on the polymers with the configuration of indium tin oxide (ITO)/poly(3,4‐ethylene dioxythiophene) : poly(styrene sulfonate) (PEDOT : PSS)/polymer/Ca/Al were fabricated. The electroluminescence efficiency of BE‐co‐MEH–PPV reached 1.64 cd/A, which was much higher than that of BE–PPV (0.68 cd/A) and a little higher than that of MEH–PPV (1.59 cd/A). Photovoltaic properties of the polymer were studied with the device configuration of ITO/PEDOT : PSS/polymer : [6,6J‐phenyl‐C61‐butyric acid methyl ester] (PCBM)/Mg/Al. The power conversion efficiency of the device based on the blend of BE‐co‐MEH–PPV and PCBM with a weight ratio of 1 : 3 reached 1.41% under the illumination of air mass 1.5 (AM1.5) (80 mW/cm2), and this was an improvement in comparison with 0.24% for BE–PPV and 1.32% for MEH–PPV under the same experimental conditions. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008  相似文献   

13.
A simplified route to regio‐regular poly(3‐alkylthiophene)s (P3AT) with predetermined molecular weights and low molecular weight distributions based on the chain‐growth GRIM polymerisation of 2,5‐dibromo‐3‐alkylthiophenes is detailed. It is proposed by way of in‐depth 13C‐, 1H‐ and two‐dimensional NMR characterisations that the resulting P3ATs are quasi‐100% regio‐regular except for one regio‐irregular pair at one chain‐end. It is probable that chain‐end groups exhibit reduced conjugation with the rest of the polymer. A comparison of the preparation of poly(3‐hexylthiophene) and poly(3‐butylthiophene) (P3BT) is presented. New methods required for the hydrogenation, formylation and bromomethylation of the chain‐ends of P3BT, necessary to overcome its poor solubility and low reactivity, are described. Copyright © 2006 Society of Chemical Industry  相似文献   

14.
This research focuses on the synthesis of ethyl and ethoxy substituted polyaniline with poly(styrenesulfonic acid) comprising a poly(o‐phenetidine)–poly(styrenesulfonic acid) [P(O? P)‐PSSA] and poly(2‐ethylaniline)–poly(styrenesulfonic acid) [P(2‐E)‐PSSA]. The complexes P(O? P)‐PSSA and P(2‐E)‐PSSA were prepared by chemical polymerization of monomer (o‐phenetidine, 2‐ethylaniline) with PSSA using an oxidant of ammonium persulfate in 1M HCl solution; polyaniline (PANI), poly(2‐ethylaniline) (P2E), poly(o‐pheneditine) (POP), and polyaniline‐poly(styrenesulfonic acid) (PANI‐PSSA) also were prepared by chemical polymerization to be the reference samples. The products were characterized by IR, VIS, EPR, water solubility, elemental analysis, conductivity, SEM, and TEM. IR spectral studies shown that the structure of P(2‐E)‐PSSA and P(O? P)‐PSSA complexes is similar to that of polyaniline. EPR and visible spectra indicate the formation of polarons. The morphology of the blend was investigated by measured SEM and TEM, indicating the conducting component and electrically conductive property of the polymer complexes. The pH value for deprotonation [pH ≥ 9.5 for P(2‐E)‐PSSA and pH ≥ 8.0 for P(O? P)‐PSSA] are higher than that of corresponding HCl salts, indicating an intimate interaction between polymer chains. Elemental analysis results show that P(O? P)‐PSSA has a nitrogen‐to‐sulfur ratio of ~52%, larger than that for P(2‐E)‐PSSA, ~41%. The conductivity of the complexes is around 10?2S/cm, and the solubility of P(2‐E)‐PSSA and P(O? P)‐PSSA in water is 2.9 and 1.9 g/L, respectively. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 1198–1205, 2005  相似文献   

15.
A series of combined liquid crystalline poly(bis‐4,4′‐oxy‐α‐methylstilbene‐4‐substituted (X) phenylazo‐4′‐phenyloxydecylphosphate ester)s bearing photoreactive mesogenic units were synthesized. FTIR and 1H NMR spectroscopy confirmed the structures of these polymers. The inherent viscosities of the polymers were found to be in the range 0.45–0.65 dL g?1. Polarizing optical microscopy (POM) exhibited birefringent liquid crystalline melt properties. The thermal properties of all of the polymers were studied by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The photochemical properties of these polymers were studied by UV‐visible and fluorescence spectroscopy. The influence of the photoinduced EZ (transcis) isomerization of the various terminal substituents of the side‐chain azobenzenes was investigated. The kinetics of the photoisomerization process reveal the switching times for the conversion between the trans‐ and cis‐ forms of the azobenzene units. The photo‐optical properties of these polymers exhibited layered smectic phases and showed good photoinduced properties in their mesomorphic states. Copyright © 2005 Society of Chemical Industry  相似文献   

16.
Two molecularly imprinted polymers (MIPs) – poly(methacrylic acid‐co‐TRIM) (TRIM, trimethylolpropanetrimethacrylate) and poly(acylamide‐co‐TRIM) – were synthesized in different solvents for the selective recovery of isovaleric acid (template) generated during the anaerobic digestion process. The chemical and structural characterizations of the synthetic adsorbent were carried out by Fourier transform infrared spectroscopy, TGA and porosimetry through N2 adsorption–desorption isotherms. The selective and adsorptive performances of the imprinted polymers were evaluated by kinetic, isothermal, thermodynamic and selectivity studies and by adsorbent reuse experiments. The poly(methacrylic acid‐co‐TRIM) synthesized with dimethyl sulfoxide:chloroform presented higher selectivity and adsorption capacity for isovaleric acid in the presence of six volatile fatty acids. The kinetic results were well adjusted to the pseudo‐nth order and intraparticle diffusion models, leading to k values of 10?4 and 6 × 10?5 for the best synthesis of MIPs and not‐imprinted polymers, respectively. Moreover, the Sips model best described the adsorption isotherm and generated a maximum adsorption capacity of ca 209 mg g?1 (at 25 °C). Cycles of MIP use–desorption–reuse indicated that the selective adsorbent performed better than commercial adsorbents, losing less than 3% of adsorption capacity after three cycles. © 2018 Society of Chemical Industry  相似文献   

17.
The water‐soluble polymers poly(styrene sulfonic acid‐co‐maleic acid) and poly(acrylic acid‐co‐maleic acid) were investigated with respect to their metal‐ion‐binding ability with ultrafiltration. The studied metal ions included Ag(I), Cu(II), Ni(II), Co(II), Ca(II), Mg(II), Pb(II), Cd(II), Zn(II), Al(III), and Cr(III) ions. The retention properties of the polyelectrolytes for the metal ions depended strongly on the ligand type. As for the carboxylate ligands, with increasing concentration and pH, the metal‐binding affinity increased. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 95: 1091–1099, 2005  相似文献   

18.
Combination of cationic, redox free radical, and thermal free radical polymerizations was performed to obtain linear and star polytetramethylene oxide (poly‐THF)‐polymethyl methacrylate (PMMA)/polystyrene (PSt) multiblock copolymers. Cationic polymerization of THF was initiated by the mixture of AgSbF6 and bis(4,4′ bromo‐methyl benzoyl) peroxide (BBP) or bis (3,5,3′,5′ dibromomethyl benzoyl) peroxide (BDBP) at 20°C to obtain linear and star poly‐THF initiators with Mw varying from 7,500 to 59,000 Da. Poly‐THF samples with hydroxyl ends were used in the methyl methacrylate (MMA) polymerization in the presence of Ce(IV) salt at 40°C to obtain poly(THF‐b‐MMA) block copolymers containing the peroxide group in the middle. Poly(MMA‐b‐THF) linear and star block copolymers having the peroxide group in the chain were used in the polymerization of methyl methacrylate (MMA) and styrene (St) at 80°C to obtain PMMA‐b‐PTHF‐b‐PMMA and PMMA‐b‐PTHF‐b‐PSt linear and star multiblock copolymers. Polymers obtained were characterizated by GPC, FT‐IR, DSC, TGA, 1H‐NMR, and 13C‐NMR techniques and the fractional precipitation method. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 219–226, 2004  相似文献   

19.
An in situ–generated tetrafunctional samarium enolate from the reduction of 1,1,1,1‐tetra(2‐bromoisobutyryloxymethyl)methane with divalent samarium complexes [Sm(PPh2)2 and SmI2] in tetrahydrofuran has proven to initiate the ring‐opening polymerization of ?‐caprolactone (CL) giving star‐shaped aliphatic polyesters. The polymerization proceeded with quantitative conversions at room temperature in 2 h and exhibited good controllability of the molecular weight of polymer. The resulting four‐armed poly(?‐caprolactone) (PCL) was fractionated, and the dilute‐solution properties of the fractions were studied in tetrahydrofuran and toluene at 30°C. The Mark–Houwink relations for these solvents were [η] = 2.73 × 10?2Mw0.74 and [η] = 1.97 × 10?2Mw0.75, respectively. In addition, the unperturbed dimensions of the star‐shaped PCL systems were also evaluated, and a significant solvent effect was observed. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 175–182, 2006  相似文献   

20.
Novel amphiphilic copolymeric gels were developed to immobilize lipase. NIPA‐co‐PEGMEA gels were prepared by copolymerizing N‐isopropylacrylamide (NIPA) as a thermosensitive and amphiphilic component and poly(ethylene glycol) methyl ether acrylate (PEGMEA) as a hydrophilic component in aqueous media. The gels can absorb organic solvents at temperatures higher than the lower critical solution temperature owing to the thermosensitive and amphiphilic properties of poly(NIPA). The lipase immobilized within the NIPA‐co‐PEGMEA gel, which had a NIPA : PEGMEA composition of 950 : 50 mol/m3, successfully catalyzed the esterification of oleic acid and ethanol without loss of activity during repeated use within 20–40°C. The activity of the immobilized lipase was considerably higher than that of free lipase. The NIPA‐co‐PEGMEA gels provide a structure that allows the immobilized lipase to work actively in an aqueous environment and with the dispersed state of the lipase in the gels. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41905.  相似文献   

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