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1.
Highly luminescent, core–shell, single‐walled carbon nanotube–poly[2‐methoxy‐5‐(2′‐ethylhexyloxy)?1,4‐phenylene vinylene] (MEH‐PPV) one‐dimensional networks were synthesized by a multicycle unstable micellization method. The current–voltage data indicated that the charge transport within the nanowire network remained Ohmic, with the differential conductance scaling linearly with temperature in the temperature range of about 120 to 300 K. Further analysis based on the comparative study involving photoluminescence and Raman spectroscopic tests pointed to interchain interactions and nanotube–polymer interface as primary factors influencing the electronic characteristics of the processed samples. Likewise, steady‐state photoconduction tests confirmed that the heterointerface played a dominant role behind the increased photoresponse induced by exciton annihilation at a low bias regime. The study helped us identify the underlying physical mechanisms that controlled the optical, electrical, and photoconduction properties of the MEH‐PPV–carbon nanotube heteronetworks. Potentially, this will open a door to the development of next generation, low‐cost, all‐organic nanooptoelectronic devices and systems. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2014 , 131, 40029.  相似文献   

2.
Polyphenylene (PP) with NH2 side groups, namely, PFluNH 2 , was synthesized by the Pd‐catalyzed reaction of 2,5‐dibromoaniline with 9,9‐dihexylfluorene‐2,7‐diboronic acid bis(1,3‐propanediol) ester. The reaction of PFluNH 2 with 1‐hexyl‐1′‐(2,4‐dinitrophenyl)‐4,4′‐bipyridinium diiodide ( SaltBPy(I?) ) eliminated 2,4‐dinitroaniline to yield PPs with viologen (1,1′‐disubstituted 4,4′‐bipyridinium dications), PFluBPy(I?) . The reaction of PFluBPy(I?) with Li+TCNQ ? resulted in anion exchange between Cl ? and TCNQ ? , and yielded PFluBPy(TCNQ?) . The reaction of PFluBPy(TCNQ?) with the neutral TCNQ0 resulted in an interaction between TCNQ ? and TCNQ0, and yielded PFluBPy(TCNQ?‐TCNQ0) . Cyclic voltammetry measurements suggested that an electrochemical reduction of the viologen moiety and oxidation of the polymer backbone within PFluBPy(TCNQ?) and PFluBPy(TCNQ?‐TCNQ0) . Furthermore, this reaction was accompanied by electrochromism. The electric conductivities (σ) of the pellets molded from PFluBPy(TCNQ?) to PFluBPy(TCNQ?‐TCNQ0) were 2.7 × 10 ? 4 and 4.2 × 10 ? 4 Scm ? 1, respectively; these σ values were higher than that observed for PFluNH 2 (σ < 10 ? 8 Scm ? 1) due to the self‐doping in the polymers. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013  相似文献   

3.
Six different phosphazene polymers have been synthesized with varying ratios of 2‐(2‐methoxyethoxy)ethanol and diacetone D ‐glucofuranose to determine how these pendant groups affect the physical, chemical, and thermal characteristics of these terpolymers. Diacetone D ‐glucofuranose serves as the hydrophobic substituent and 2‐(2‐methoxyethoxy)ethanol is the hydrophilic substituent on the phosphazene backbone. Characteristics of the polymers made in this study reflect a blend of the two substituents, ranging from powders to viscous fluids. Thermal analysis was used to quantify the thermal stability and water swellability of the polymers. Additionally, DSC was employed to determine composition based on the Fox equation. Compositions were then verified by integratable proton NMR indicating the validity of the Fox equation for predicting Tg transitions in phosphazene terpolymers. Laser light scattering (LLS) revealed that the weight‐average molecular weights were in the 107 g mol−1 range with mean square radii between 150 and 200 nm. © 2000 Society of Chemical Industry  相似文献   

4.
Poly(vinylidene fluoride) (PVDF) membranes with exclusive β‐form have been directly obtained by immersion precipitation from the mixed solvents containing an ionic liquid (IL). In contrast, without the IL only the α‐form is generated. The ion–dipole interactions between the IL and PVDF chains should account for the formation of the β‐form with TTTT conformation. In addition, the presence of the IL accelerates the crystallization and gelation of PVDF, responsible for the particulate morphology and high water flux in the membranes. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40505.  相似文献   

5.
The new exo-N-3,5-bis(trifluoromethyl)phenyl-7-oxanorbornene-5,6-dicarboximide (TFmPhONDI, 2), was synthesized and polymerized via ring opening metathesis polymerization (ROMP) using tricyclohexylphosphine [1,3-bis(2,4,6-trimethylphenyl)-4,5-dihydroimidazolilydene][benzylidene] ruthenium dichloride (I) to produce the corresponding PTFmPhONDI (3). Gas permeability, diffusion and solubility coefficients of PTFmPhONDI (3) were determined by transient permeation for five gases He, CO2, O2, N2 and CH4. The larger gas permeability and diffusion coefficients of 3 compared to polynorbornene dicarboximides without fluorine pendant groups were attributed to a lower polymer chain packing due to the effect of the CF3 groups in the lateral phenyl moiety pending at positions 3 and 5.  相似文献   

6.
A series of thermoresponsive poly(γ‐propyl‐L‐glutamate)‐graft‐(oligo ethylene glycol)s (PPLG‐g‐OEGs) with different main‐chain and side‐chain lengths have been synthesized via copper‐mediated alkyne‐azide 1,3‐dipolar cycloaddition between poly(γ‐azidopropyl‐L‐glutamate)s (PAPLG) and propargyl terminated oligo ethylene glycols (Pr‐OEGs). Fourier transform infrared spectrometer analysis revealed that PAPLG10 adopted 39.4% β‐sheet, 47.4% α‐helix, and 13.2% random coil while PAPLG with longer main‐chain length (DP = 37 and 88) and PPLG‐g‐OEGs adopted exclusive α‐helix in the solid state. Circular dichroism analysis revealed that PPLG‐g‐OEGs adopted α‐helical conformations with helicities in the range of 50~100%. The thermoresponsive behaviors of PPLG‐g‐OEGs in water have been studied by dynamic light scattering. The polymer concentration, main‐/side‐chain length, and helicity collectively affected their cloud point temperatures. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 41022.  相似文献   

7.
A polymeric gas separation membrane utilizing polybenzimidazole based on 4,4′‐(hexafluoroisopropylidene)bis(benzoic acid) was prepared. The synthesized membrane has an effective permeating area of 8.3 cm2 and a thickness of 30 ± 2 µm. Gas permeation properties of the membrane were determined using H2, CO2, CO, and N2 at temperatures ranging from 24°C to 200°C. The PBI‐HFA membranes not only exhibited excellent H2 permeability, but it also displayed superior gas separation performance particularly for H2/N2 and H2/CO2. The permeation parameters for both permeability and selectivity [ and α(H2/N2); and α(H2/CO2)] obtained for the new material were found to be dependent on trans‐membrane pressure difference as well as temperature, and were found to surpass those reported by Robeson in 2008. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42371.  相似文献   

8.
The isocyanate‐terminated linear polyurethane prepolymer (LPPU) was successfully synthesized via step‐by‐step polymerization, with isophorone disocyanate (IPDI) and polytetramethylene ether glycol (PTMG, Mn = 2000 g/mol) used as raw materials, dibutyltin dilaurate (DBTDL) as the catalyst, 1,4‐butanediol (BDO) as the chain extender and anhydrous ethanol (EtOH) as the blocking agent. Then the hyperbranched poly (urethane‐urea) (HBPU) containing amino groups was synthesized by grafting LPPU on amino‐terminated hyperbranched polymers (NH2‐HBP). The molecular structure of LPPU and HBPU were characterized by means of FT‐IR and 1H‐NMR. It was founded that LPPU and HBPU were successfully synthesized as anticipated. The thermal stability and crystalline morphology of LPPU and HBPU were characterized and analyzed by TG and XRD. Additionally, it was also found that, after addition of 10% HBPU, the water absorption rate, water vapor transmission rate, and water vapor permeability increased markedly by 162.02%, 400.00%, 260.00%, respectively. The tensile strength of membrane decreased by 24.57% and the elongation at break increased by 26.92%. Compared with the leather finished by commercial PU finishing agent, the leather finished by HBPU presented better properties. The water vapor permeability of the leather finished by increased by 13.0%, and the dry‐ and wet‐rub resistances and the physical and mechanical performances were excellent. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 44139.  相似文献   

9.
The apparent inability of a single biomaterial to meet all the requirements for tissue engineering scaffolds has led to continual research in novel engineered biomaterials. One method to provide new materials and fine‐tune their properties is via mixing materials. In this study, a biodegradable powder blend of poly(ε‐caprolactone) (PCL), polyglycolide (PGA), and poly(ethylene oxide) (PEO) was prepared and three‐dimensional interconnected porous PCL/PGA scaffolds were fabricated by combining cryomilling and compression molding/polymer leaching techniques. The resultant porous scaffolds exhibited co‐continuous morphologies with ~50% porosity. Mean pore sizes of 24 and 56 μm were achieved by varying milling time. The scaffolds displayed high mechanical properties and water uptake, in addition to a remarkably fast degradation rate. The results demonstrate the potential of this fabrication approach to obtain PCL/PGA blend scaffolds with interconnected porosity. In general, these results provide significant insight into an approach that will lead to the development of new composites and blends in scaffold manufacturing. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42471.  相似文献   

10.
A new symmetrically substituted cationic monomer bis[3‐(diethoxyphosphoryl)propyl]diallylammonium chloride has been synthesized and cyclopolymerized to give the corresponding cationic polyelectrolyte (+) (CPE) bearing two identical (diethoxyphosphoryl)propyl penedents on the pyrrolidinium repeating units. The hydrolysis of the phosphonate ester in (+) (CPE) gave a pH‐responsive cationic polyacid (+) (CPA) bearing the motifs of a tetrabasic acid. The (+) (CPA) under pH‐induced transformation was converted into a water‐insoluble polyzwitterion acid (±) (PZA) or water‐soluble polyzwitterion/monoanion (± ?) (PZMAN) or polyzwitterion/dianion (± =) (PZDAN) or polyzwitterion/trianion (± ≡) (PZTAN), all having identical degree of polymerization. The interesting solubility and viscosity behaviors of the polymers have been investigated in some detail. The apparent protonation constants of the anionic centers in (± ≡) (PZTAN) and its corresponding monomer (± ≡) (ZTAN) have been determined. Evaluation of antiscaling properties of the PZA using supersaturated solutions of CaSO4 revealed ≈100% scale inhibition efficiency at a meager concentration of 10 ppm for a duration over 71 h at 40°C. The PZA has the potential to be an effective antiscalant in Reverse Osmosis plants. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40615.  相似文献   

11.
Homopolymers and copolymers of poly(arylene ether nitrile) (PAEN)‐bearing pendant xanthene groups were prepared by the nucleophilic substitution reaction of 2,6‐difluorobenzonitrile with 9,9‐bis(4‐hydroxyphenyl)xanthene (BHPX) and with various molar proportions of BHPX to hydroquinone (100/0 to 40/60) with N‐methyl‐2‐pyrrolidone (NMP) as a solvent in the presence of anhydrous potassium carbonate. These polymers had inherent viscosities between 0.61 and 1.08 dL/g, and their weight‐average molecular weights and number‐average molecular weights were in the ranges 34,200–40,800 and 17,800–20,200, respectively. All of the PAENs were amorphous and were soluble in dipolar aprotic solvents, including NMP, N,N‐dimethylformamide, and N,N‐dimethylacetamide and even in tetrahydrofuran and chloroform at room temperature. The resulting polymers showed glass‐transition temperatures (Tg's) between 220 and 257°C, and the Tg values of the copolymers were found to increase with increasing BHPX unit content in the polymer. Thermogravimetric studies showed that all of the polymers were stable up to 422°C with 10% weight loss temperatures ranging from 467 to 483°C and char yields of 54–64% at 700°C in nitrogen. All of the new PAENs could be cast into transparent, strong, and flexible films with tensile strengths of 106–123 MPa, elongations at break of 13–17%, and tensile moduli of 3.2–3.7 GPa. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011  相似文献   

12.
Biodegradable poly(ε‐caprolactone‐co‐δ‐valerolactone) copolymers were synthesized and investigated to study their behavior in aqueous medium. The copolyesters were produced by ring opening polymerization between ε‐caprolactone (CL) and δ‐valerolactone (VL) in bulk at 140°C using tin(II) octoate as catalyst. They were characterized by using 1H NMR, size exclusion chromatography, differential scanning calorimetry, and MALDI TOF mass spectrometry. Reactivity ratio determination gave an insight on their microstructure. Hydration, hydrolytic degradation, and biocide release of P(CL‐VL) films with different molecular weights values were studied. A one‐order kinetic whose rate constant decreases with copolymer macromolecular weight was observed. Although the molecular weight decrease remained relatively weak after 8 months of immersion, a correlation between molecular weight and hydrolysis rate was shown by high performance liquid chromatography‐mass spectrometry. The ability of the P(CL‐VL) films to release active compounds dispersed in the films was studied by atomic absorption spectroscopy. The release behavior of all copolymers was identical with a zero‐order kinetic. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43007.  相似文献   

13.
The free‐standing, flexible, and ferroelectric films of poly(vinylidenefluoride‐co‐hexafluoropropylene) [P(VDF‐HFP)] were prepared by spin coating method. The ferroelectric phase of the films was enhanced by adding magnesium nitrate Mg(NO3)2 in different wt % as the additive during the film fabrication. The effects on the structural, compositional, morphological, ferroelectric, dielectric, and leakage current behaviors of the films due to the addition of salt were analyzed. Based on the X‐ray diffraction (XRD) patterns and Fourier Transform Infrared (FTIR) spectra, it is confirmed that the addition of Mg(NO3)2 promotes the electroactive β phase that induces the ferroelectric property. The fiber‐like topography of the films exhibits a nodule‐like structure, and the roughness of the films increases by the addition of Mg(NO3)2. The ferroelectric studies show the higher polarization values for the composite films than that of the plain P(VDF‐HFP) film. The Piezo‐response force microscope images also confirm the domain switching behavior of the samples. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 44008.  相似文献   

14.
Nowadays, new methods for gas‐separation processes are being quickly developed. The separation of CH4/CO2 and CH4/H2 is usually the subject of most related research studies, especially in the membrane gas‐separation process, because of their important role in industry. In this study, we attempted to improve the separation properties of a polysulfone/zeolite 4A mixed‐matrix membrane by modifying the zeolite particle surface. The method included a simple ion‐exchange reaction of magnesium chloride with ammonium hydroxide that yielded the formation and precipitation of magnesium hydroxide whiskers on the surface of the zeolites. The whiskers could omit most of the nonselective voids by interlocking the polymer chains through them and, consequently, improve the permeability, selectivity, and elastic modulus of the membranes. X‐ray diffraction, energy‐dispersive X‐ray spectroscopy, scanning electron microscopy (SEM), Fourier transform infrared spectroscopy, and dynamic mechanical analysis proved all the changes recorded after the particle and membrane treatments. SEM images showed the petal‐like morphology of the whiskers that formed on the surface of the particles after the reaction against the smooth surface of the untreated zeolite. At a 30 wt % loading of particles in the polymeric matrix, the selectivities for H2/CH4 and CO2/CH4 increased by 69 and 56%, respectively; in contrast, the H2 and CO2 permeabilities decreased by 2.5 and 10%, respectively. The modulus of elasticity for the treated membrane also increased by 14 and 30% compared to those of the pure and untreated membranes, respectively. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 44329.  相似文献   

15.
The novel block copolymer poly(benzyl glutamate) (PBLG)–polomamer–PBLG were synthesized from glutamic acid and poloxamer in six steps with three different molecular weights, and another new block copolymer, poly(glutamic acid) (PGA)–poloxamer–PGA, was obtained by the benzyl deprotection of PBLG–poloxamer–PBLG. The obtained compounds were characterized by IR spectroscopy, gel permeation chromatography, and 1H‐NMR. The in vitro biological degradation and water absorption of PBLG showed that a greater proportion of PBLG in the copolymer led to a slower degradation and weaker water absorption, so the speed of degradation and water absorption could be adjusted through adjustment of the ratio of poloxamer. Both PBLG–poloxamer–PBLG and PGA–poloxamer–PGA exhibited lower cytotoxicity and good biocompatibility in the methyl thiazolyl tetrazolium (MTT) assay. The results show that both block polymers are promising as drug‐carrier materials. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013  相似文献   

16.
Poly(vinyl alcohol) was modified by an aldehyde acetal reaction with 2,4,6‐trinitrophenylacetaldehyde to give a new energetic polymer poly(vinyl 2,4,6‐trinitrophenylacetal) (PVTNP). The structure of PVTNP was characterized by elemental analysis, ultraviolet–visible spectroscopy, Fourier transform infrared spectroscopy, and nuclear magnetic resonance spectra. The glass‐transition temperature of PVTNP was evaluated by differential scanning calorimetry (DSC), and the thermal stability of PVTNP was tested by differential thermal analysis (DTA) and thermogravimetric analysis (TGA). DSC traces showed that the PVTNP polymer had one single glass‐transition temperature at 105.3°C. DTA and TGA curves showed that the thermooxidative degradation of PVTNP in air was a three‐step reaction, and the percentage of degraded PVTNP reached nearly 100% at 650°C. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011  相似文献   

17.
A novel solid–solid phase‐change energy storage material was synthesized by the aqueous phase precipitation polymerization. The amphiphilic polyethylene glycol‐maleic acid monoester macromonomer (MAPEG) with a double bond and a terminal carboxyl was the side chain and the polyacrylonitrile (PAN) was a skeleton. The chemical structure and thermal properties of the graft copolymer were investigated. The results indicated that the MAPEG chains were successfully grafted onto the PAN backbone. The graft copolymer possess good thermal reliability and the phase‐transition temperature is in the temperature range of human comfort, meanwhile, the melting enthalpy could reach 74.16 J/g and the crystallization enthalpy could reach 65.40 J/g, accounting for theoretical enthalpy value of 89 and 93%, respectively. Besides, optimum conditions of synthesizing the graft copolymer were determined by orthogonal experiment. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40152.  相似文献   

18.
Cellulose acetate (CA) is well known glassy polymer used in the fabrication of gas‐separation membranes. In this study, 5,11,17,23‐tetrakis(N‐morpholinomethyl)‐25,26,27,28‐tetrahydroxycalix[4]arene (CL) was blended with CA to study the gas‐permeation behavior for CO2, N2, and CH4 gases. We prepared the pure CA and CA/CL blended membranes by following a diffusion‐induced phase‐separation method. Three different concentrations of CL (3, 10, and 30 wt %) were selected for membrane preparation. The CA/CL blended membranes were then characterized via Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), atomic force microscopy (AFM), and X‐ray diffraction analysis. The homogeneous blending of CL and CA was confirmed in the CA/CL blended membranes by both SEM and AFM analysis. In addition to this, the surface roughness of the CA/CL blended membranes also increased with increasing CL concentration. FTIR analysis described the structural modification in the CA polymer after it was blended with CL too. Furthermore, CL improved the tensile strength of the CA membrane appreciably from 0.160 to 1.28 MPa, but this trend was not linear with the increase in the CL concentration. CO2, CH4, and N2 gases were used for gas‐permeation experiments at 4 bars. With the permeation experiments, we concluded that permeability of N2 was higher in comparison to those of CO2 and CH4 through the CA/CL blended membranes. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2014 , 131, 39985.  相似文献   

19.
A macromolecular hindered phenol antioxidant, polyhydroxylated polybutadiene containing thioether binding 2,2′‐thiobis(4‐methyl‐6‐tert‐butylphenol) (PHPBT‐b‐TPH), was synthesized via a two‐step nucleophilic addition reaction using isophorone diisocyanate (IPDI) as linkage. First, the ? OH groups of PHPBT reacted with secondary ? NCO groups of IPDI to form the adduct PHPBT‐NCO, then the PHPBT‐b‐TPH was obtained by one phenolic ? OH of 2,2′‐thiobis(4‐methyl‐6‐tert‐butylphenol) (TPH) reacting with the PHPBT‐NCO. The PHPBT‐b‐TPH was characterized by Fourier transform infrared spectroscopy, 1H nuclear magnetic resonance (1H‐NMR), 13C‐NMR, and thermogravimetric analysis, and its antioxidant activity in natural rubber was studied by an accelerated aging test. Influences of reaction conditions on the two nucleophilic reactions between ? OH group and ? NCO group were investigated. In addition, catalytic mechanism for the reaction between PHPBT‐NCO and TPH was discussed. The results showed that the adduct PHPBT‐NCO could be obtained by using dibutyltin dilaurate (DBTDL) as catalyst, and the suitable temperature and DBTDL amount were 35°C and 3 wt %, respectively. However, triethylamine (TEA) was more efficient than DBTDL to catalyze the reaction between PHPBT‐NCO and TPH because of steric hindrance effect. In addition, it was found that the thermal stability and antioxidant activity of PHPBT‐b‐TPH were higher than those of the low molecular weight antioxidant TPH. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40942.  相似文献   

20.
This work investigates the ability of 1‐ethyl‐3‐methylimidazolium methanesulphate ([EMIM][MeSO3]) as a green and tuneable solvent for denitrification and desulphurisation studies. Experimental density, surface tension and refractive index data have been measured for the following systems: [EMIM][MeSO3] (1) + pyridine (2), [EMIM][MeSO3] (1) + pyrrole (2), [EMIM][MeSO3] (1) + quinoline (2), [EMIM][MeSO3] (1) + indoline (2), [EMIM][MeSO3] (1) + thiophene (2) and [EMIM][MeSO3] (1) + water (2) over the entire mole fraction of [EMIM][MeSO3] at T = 298.15–323.15 K and P = 1 bar. Further from experimental density, surface tension and refractive index, coefficient of thermal expansivity, excess molar volume, deviation of surface tension and refractive index deviation were also calculated. It was found that the heteroaromatic nitrogen/sulphur compounds are completely miscible in [EMIM][MeSO3]. The surface tension values were found to increase while the refractive index decreases with increasing mole fraction of [EMIM][MeSO3]. The experimental values for surface tension increased in the order: pyridine > thiophene > pyrrole > indoline > quinoline > water and for refractive index: pyridine > pyrrole > indoline > quinoline > thiophene > water. It was found that the composition of [EMIM][MeSO3] has a greater influence than temperature in deciding the surface, optical and thermodynamic properties for similar molecular interaction such as IL–thiophene and IL–pyrrole than dissimilar molecules such as IL–water. Further quantum chemical‐based COSMO‐RS tool was used to estimate the activity coefficient at different composition. © 2012 Canadian Society for Chemical Engineering  相似文献   

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