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1.
Lipophilic salts based on tetraphenylborate derivatives [e.g., potassium tetrakis(p‐chlorophenyl)borate (KTpClPB), sodium tetraphenylborate (NaTPB), and cesium tetrakis(3‐methylphenyl)borate are essential ingredients used in the preparation of solvent polymeric cation‐selective membranes. The effects of such lipophilic salts on the physical properties of a polyurethane (PU) matrix comprising 4,4′‐diphenylmethane diisocyanate, 1,4‐butanediol, and poly(tetramethylene ether glycol) were examined. Differential scanning calorimetry measurements revealed that the sodium and potassium salts doped in PU increased the glass‐transition temperatures (Tg) of the matrix, while the film containing cesium salt exhibited slightly decreased Tg. The temperature dependence of the ionic conductivity for PU60 films doped with KTpClPB is well described by the Arrhenius‐type equation, and that doped with NaTPB is described by the Vogel–Tammann–Fulcher (VTF)‐type equation. The temperature dependence of the ionic conductivity on the VTF‐type equation suggests that the transport of sodium ions in the PU60 matrix is more strongly coupled to the soft segmental motion, and potassium ions are decoupled from the polymer host and transported by activated hopping. The effect of added salt on the internal structure of PU membranes was investigated by measuring the ratio between the free and hydrogen‐bonded CO bands at 1703 and 1730 cm−1, respectively. The results showed that the ether oxygens in the soft segment chains are strongly coupled to the potassium or sodium, but much less to cesium. The potentiometric properties of these lipophilic additive doped PU membranes were characterized by incorporating valinomycin and 4‐tert‐butylcalix[4]arene‐tetraacetic acid tetraethylester as potassium‐ and sodium‐selective ionophores, respectively. Their response behavior could be explained by the observed physical characteristics. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 618–625, 2001  相似文献   

2.
BACKGROUND: Mercury electrodeless discharge lamps (Hg‐EDLs) were used to generate UV radiation when exposed to a microwave field. EDLs were coated with doped TiO2 in the form of thin films containing transition metal ions Mn+ (M = Fe, Co, Ni, V, Cr, Mn, Zr, Ag). Photocatalytic degradation of mono‐chloroacetic acid (MCAA) to HCl, CO2, and H2O, and decomposition of Rhodamine B on the thin films were investigated in detail. RESULTS: Polycrystalline thin doped TiO2 films were prepared by dip‐coating of EDL via a sol–gel method using titanium n‐butoxide, acetylacetone, and a transition metal acetylacetonate. The films were characterized by Raman spectroscopy, UV/Vis absorption spectroscopy, X‐ray photoelectron spectroscopy (XPS), electron microprobe analysis and by atomic force microscopy (AFM). The photocatalytic activity of doped TiO2 films was monitored in the decomposition of Rhodamine B in water. Compared with the pure TiO2 film, the UV/Vis spectra of V, Zr and Ag‐doped TiO2 showed significant absorption in the visible region, and hence the photocatalytic degradation of MCAA had increased. The best apparent degradation rate constant (0.0125 min?1), which was higher than that on the pure TiO2 film by a factor of 1.7, was obtained with the Ag(3%)/TiO2 photocatalyst. The effect of doping level of vanadium acetylacetonate on the photocatalytic efficiency of the V‐doped TiO2 was determined. CONCLUSIONS: Transition metal ion‐doped TiO2 thin films showed significant absorption in the visible region. The metal doped TiO2 photocatalyst (with an appropriate amount of V, Zr and Ag) on the Hg‐EDLs increased the degradation efficiency of MCAA in a microwave field. Copyright © 2009 Society of Chemical Industry  相似文献   

3.
Novel aqueous polyurethane (PU) hybrid dispersions were successfully prepared with 5–15 mol % functionalized hexamethylene diisocynate trimer modified by N‐(n‐butyl)‐3‐aminopropyltriethoxysilane and dihydroxylpropyl‐terminated siloxane oligomers (TS). The results of the differential scanning calorimetry and X‐ray diffraction tests show that the degree of segment order was reduced by the introduction of TS. The hybrid polymer films with TS introduced into the PU backbone displayed excellent water and xylene resistance. Atomic force microscopy showed that the films had a smooth surface. It was noticeable that the tensile strength (σb) and Young's modulus of the films increased simultaneously when TS was incorporated into PU; σb of the PU15 film with 15 mol % TS was much higher than that of the neat PU0 film, and the breaking elongation of the film with 10 mol % TS was clearly higher than that of the other films. The results indicate that an appropriate content of TS significantly improved the properties of the aqueous PU hybrids. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011  相似文献   

4.
Polyurethane‐nitrolignin (PUNL), a new network polymer, was synthesized from a castor oil based–polyurethane (PU) prepolymer and nitrolignin (NL) with a weight‐average molecular weight of 20.6 × 104 and a content of 1.4–10%. The structure and miscibility of PUNL films prepared by solution casting were investigated by infrared spectroscopy and transmission electron microscopy. The results indicated that PUNL2 film, which had a 2.8% NL content, was the most miscible, and its tensile strength (σb) and breaking elongation (?b) were 2 times higher than that of PU film. The crosslink densities of PUNL films increased with the increase of NL content until about 3%, similar to the variety of the mechanical properties. Thermogravimetric analysis revealed that the thermal stability of PUNL films was slightly higher than that of PU. Covalent bonds occurred between PU prepolymer and the NL in the PUNL films, forming crosslink networks, which resulted in the enhancement of mechanical properties and thermal stability. NL has a far higher reactivity with PU than nitrocellulose. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 1213–1219, 2001  相似文献   

5.
A polyurethane–chitosan (PU–CH) coating was synthesized from castor-oil-based PU prepolymer and highly deacetylated and depolymerized chitosan. The films cast with the coating were used for the characterization. X-ray photoelectron spectroscopy, a surface-sensitive technique, indicated the chemical bonding between the chitosan and PU prepolymer as well as the enrichment of chitosan on the surface of the film PU–CH. Electron spin resonance (ESR) spectroscopy using the nitroxyl radical 4-hydroxy-2,2,6,6-tetramethyl piperidine-1-oxyl (4-hydroxy-TEMPO) as a reporter group was used to study the chain mobility in the film PU–CH. It was observed that T50G of the probe and the first glass transition temperature (Tg1) of the film PU–CH were 10 and 18°C higher than those in the PU film, respectively, and the activation energy (27.0 kJ mol−1) of tumbling for the probe covalently bonded with PU–CH was 12.8 kJ mol−1 higher than that of the probe with the film PU. It suggests that the molecular motion in the PU–CH was restricted by grafted and crosslinked interpenetrating polymer networks (IPNs). The results of the differential thermal analysis and thermogravimetric analysis proved that the thermostability of the film PU–CH was significantly higher than that of the film PU, and the Tg1 value is in good agreement with that calculated from ESR. It could be concluded that the IPNs resulted from the chitosan grafting and crosslinking with PU exist in the film PU–CH. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 68: 1321–1329, 1998  相似文献   

6.
1H wideline and 13C magic‐angle spinning NMR have been used to study the morphology and dynamics of latex‐cast and solution‐cast film blends of natural rubber (NR) and a polyurethane (PU) based on poly(?‐caprolactone) diol and isophorone di‐isocyanate. 1H T1 and T relaxation times have been measured, and the extent of interpenetration of the NR and PU constituents has been monitored using the Goldman–Shen technique. The NMR spectra and relaxation properties indicated that the NR and PI constituents largely occupy separated domains on a distance scale of >10 nm. The Goldman–Shen experiments indicated that there was slightly greater contact between NR and PU in the solution‐cast samples than in the latex‐cast. The tensile properties of the films have been measured. The tensile strength and initial Young's modulus pass through a maximum at a PU content of about 50 wt%. © 2002 Society of Chemical Industry  相似文献   

7.
Polymer blends based on nanostructured polyaniline (PANI) doped with hydrochloric acid (HCl) and para‐toluene sulfonic acid (PTSA) introduced into aliphatic polyurethane matrix (PU) are synthesized to produce flexible thin composite films for microwave absorbers. The effects of dopant type, PANI content and film thickness on morphologies, dielectric and microwave absorption properties in the X‐band are studied. It reveals that real and imaginary parts of the complex permittivity are proportional to filler concentrations and type of doped PANI. The PANI‐PTSA/PU films show higher permittivity and better microwave absorbing properties than PANI‐HCl/PU for the same weight fraction of PANI. The minimum reflection loss RL(dB) values for the PANI‐PTSA/PU are ?37 dB at (20% PANI and 11.6 GHz) and ?30 dB at (15% PANI and 11.3 GHz) for thicknesses of 1.2 and 1.6 mm, respectively. These high values of reflection losses make the obtained lightweight and flexible composites promising radar absorbing materials (RAM). © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40961.  相似文献   

8.
This article introduces a cellulose/polyurethane (PU) semi‐IPN‐based electroactive paper (EAPap) actuator. The fabrication process, bending actuation test, and its characteristics are explained. For the fabrication of cellulose/PU semi‐IPN EAPap actuator, cotton cellulose was dissolved into N,N‐dimethylacetamide (DMAc) and lithium chloride (LiCl) solvent system. PU prepolymer prepared by poly[di(ethylene glycol) adipate] and hexamethylene diisocyanate (HDI) was mixed with DMAc cellulose solution by stirring. The mixed solution was spin‐coated on a wafer and cured to form cellulose/PU semi‐IPN films using 1,1,1‐tris(hudroxymethyl)propane as the crosslinker. The characteristics of the cellulose/PU semi‐IPN film were investigated by FTIR, scanning electron microscopy (SEM), X‐ray diffraction pattern (XRD), and tensile test. The bending actuation performance of the actuator was evaluated in terms of free bending displacement with respect to the actuation frequencies, voltages, and humidity levels. It shows a good bending actuation at room humidity condition. The actuation principle of the actuator is also discussed. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008  相似文献   

9.
Ce3+‐doped Gd3Fe5O12 (Ce:GIG) film has a good application prospect in the field of integrated optical device. In this article, Ce:GIG and Ce,Ga:GIG films were deposited onto the quartz glass substrate by using radio‐frequency magnetron sputtering technology. The crystal phase, surface morphology, magnetization, and magnetic circular dichroism properties of films were characterized by using the X‐ray powder diffraction, atomic force microscopy, vibrating sample magnetometer, and circular dichroism spectrometer. The results show that as‐prepared Ce,Ga:GIG films has a good quality and show an excellent magneto‐optical performance, and the doping of Ga3+ ion and the annealing process have significant effect on the magnetism and magneto‐optical performances. It is expected that Ce,Ga:GIG film with a moderate Ga3+‐doping content is a better candidate than Ce:GIG and Ce:YIG films for the next generation of integrated optical isolator and other magneto‐optical equipment.  相似文献   

10.
High electrochemical active free‐standing multiwalled carbon nanotube (MWNT) films have been synthesized from aniline oligomer functionalized MWNTs (MWNT‐AO), by using filtration of the acidic phosphate ester (APE) doped MWNT‐AO dispersions. The homogeneously distributed MWNTs endowed APE/MWNT films automatically releasing from the filter membrane. The sheet resistivity of MWNT‐AO (850 Ω sq?1) showed a lower value than that of carboxyl MWNTs (1273 Ω sq?1), due to the doping effect of MWNT on aniline oligomer, confirmed by the N1s X‐ray photoelectron spectrum. However, it showed a higher sheet resistivity value of 1526 Ω sq?1 after further doped by APE, because of the presence of unreacted dopant. After removing the residual insulating dopant by the vacuum filtration, the resultant APE/MWNT films showed the sheet resistivity value as low as 131 Ω sq?1. Thermogravimetric analysis showed that the MWNT loading in the film can be over than 77%, which showed the specific capacitance as high as 249 F g?1. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40259.  相似文献   

11.
Composite films were obtained by placing a polyurethane/amylose acetate semi‐interpenetrating polymer network (SIPN) coating onto the surfaces of regenerated cellulose (RC) film. The properties of the composite film, such as tensile strength, 79.9 MPa (in dry state), 49.5 MPa (in wet state), water resistance (R), 0.62, dimensional stability (Sc), 3.0%, and water vapor permeability (P), 5.96 × 10−5 Kgm−2h−1, are better than those of the uncoated RC film or RC film with PU coating. The interfacial strength was characterized with infrared spectroscopy (IR), ultraviolet spectroscopy (UV), transmission electron microscopy (TEM), and electron probe microanalysis (EPMA). The results showed the existence of covalent and hydrogen bonds between the SIPN coat layer and the RC layer. It was also found that the PU prepolymer in the coating layer penetrated into the cellulose bulk, and reacted with the cellulose molecules, which formed another SIPN.  相似文献   

12.
The blend films of polyurethane (PU) and amino‐terminal hyperbranched polymers (HBP‐NH2) were prepared successfully by mixing HBP‐NH2 solution and PU. The rate of moisture absorption and mechanical properties were determined. The results showed that the rates of moisture absorption and vapor permeability were improved from 0.34% to 7.51% and from 161 gm?2 d?1 to 879 gm?2 d?1, respectively. The addition of HBP‐NH2 is helpful to improve the hygiene properties of PU films. Then, the structures of the blend films were characterized by IR, XRD, TG, and SEM at the same time. The results indicated that HBP‐NH2 and PU had hydrogen‐bond interaction and a certain phase separation. The blend films had good heat stability. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41383.  相似文献   

13.
This study investigates the enhanced structural, and optoelectronic properties of transparent conductive Ga‐doped MgxZn1 ? xO (GMZO) thin films with a varied magnesium (Mg) composition of 2% and 8%, respectively. The X‐ray diffraction (XRD) measurements revealed that GMZO with an 8% Mg composition shows a stronger (002) diffraction intensity and narrower linewidth than that with a 2% Mg composition. Improved crystallinity and enlarged grain size in the postgrowth thermal annealed GMZO thin films were also observed in XRD and morphological measurements by atomic force microscopy. Photoluminescence measurements were conducted to investigate the improved GMZO thin‐film quality, and the oxygen vacancy signal was found to decrease with increased Mg content, consistent with X‐ray photoelectron spectroscopy measurements. This study also shows high optical transmittance over 98%, and a low resistivity of 5.7 × 10?4 Ω·cm in Ga‐doped MgxZn1 ? xO (x = 0.02) thin film, which indicates the highly promising candidate for use in optoelectronic devices.  相似文献   

14.
A polyurethane (PU) was developed from poly(dimethylamine‐co‐epichlorohydrin‐co‐ethylenediamine) (PDMAE) and polyethylene glycol (PEG) as soft segment and 2,4‐toluene diisocyanate (TDI) incorporating as hard segment. Later PU was blended with poly(ethylene‐co‐ethyl acrylate) (PEEA). Poly(vinyl alcohol)‐functionalized carbon black (CB‐PVA) nanoparticles was used as filler. The structure, morphology, mechanical, crystallization, and shape memory behavior (heat and voltage) were investigated methodically. Due to physical interaction of the blend components, unique self‐assembled network morphology was observed. The interpenetrating network was responsible for 83% rise in tensile modulus and 46% increase in Young's modulus of PU/PEEA/CB‐PVA 1 hybrid compared with neat PU/PEEA bend. Electrical conductivity was increased to 0.2 Scm?1 with 1 wt % CB‐PVA nanofiller. The original shape of sample was almost 94% recovered using heat induced shape memory effect while 97% recovery was observed in an electric field of 40 V. Electroactive shape memory results were found better than heat stimulation effect. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43481.  相似文献   

15.
A series of semi‐interpenetrating polymer networks (semi‐IPNs) films were prepared from 20 wt % of benzyl amylose (BA) of different Mw and castor oil‐based polyurethane (PU) in N,N‐dimethylformamide (DMF). The weight‐average molecular weight (Mw), and radii of gyration (<S2>z1/2) of benzyl amylose were determined by laser scattering measurement, and the results suggested BA was in a compact coil conformation in DMF. Furthermore, the properties and miscibility of the polyurethane/benzyl amylose (PUBA) films were studied by scanning electronic microscopy, differential scanning calorimetry, dynamic mechanical thermal analysis, ultraviolet–visible spectrophotometer, and tensile testing. The PUBA films possessed much higher optical transmittance and tensile strength than the pure PU film regardless of the molecular weight of BA, but lower values of elongation at break were observed. With decreasing of the BA Mw from 9.24 × 105 to 2.69 × 105, interestingly, the elongation at break of the films increased from 135 to 326%. This might be ascribed to the decrease of crosslinking density of PU networks and the enhancement in freedom of the molecular motion. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010  相似文献   

16.
We report the superior corrosion‐resistant properties of conducting polyurethane networks of polyaniline (PANI), poly‐m‐aminophenol (PmAP), and poly‐o‐anisidine (PoA) coated on mild steel panels. These networks were prepared by blending conducting polyanilines with isocyanate‐containing prepolyurethanes. Free‐standing polyurethane films were obtained after a moisture cure for several days to ensure complete reaction of the excess isocyanate. The films were electrochemically active with conductivity in the range of 10?2 to 10?3 S/cm. The solution blends and formed films were characterized by infrared, ultraviolet, thermogravimetric analysis, and differential scanning calorimetry. Electrochemical corrosion studies of the coated films on mild steel panels showed excellent corrosion protection in the following order: PU‐PANI > PU‐PmAP > PU‐PoA. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 45806.  相似文献   

17.
Blends made up of castor oil‐based polyurethane (PU) and poly(o‐methoxyaniline) (POMA) were obtained in the form of films by casting and characterized by FTIR, UV‐Vis‐NIR spectroscopy, and electrical conductivity measurements. Doping was carried out by immersing the films in 1.0M HCl aqueous solution. Chemical bonds between NCO group of PU and NH group of POMA were observed by means of FTIR spectra. The UV‐Vis‐NIR spectra indicated that the presence of the PU in the blend does not affect doping and formation of the POMA phase. The electrical conductivity research was in the range of 10?3 S/cm. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007  相似文献   

18.
Ferroelectric Na0.5Bi4.5Ti4O15 (NaBTi) and donor Nb‐doped Na0.5Bi4.5Ti3.94Nb0.06O15 (NaBTiNb) thin films were prepared on Pt(111)/Ti/SiO2/Si(100) substrates using a chemical solution deposition method. The doping with Nb5+‐ions leads to tremendous improvements in the ferroelectric properties of the NaBTiNb thin film. Room‐temperature ferroelectricity with a large remnant polarization (2Pr) of 64.1 μC/cm2 and a low coercive field (2Ec) of 165 kV/cm at an applied electric field of 475 kV/cm was observed for the NaBTiNb thin film. The polarization fatigue study revealed that the NaBTiNb thin film exhibited good fatigue endurance compared with the NaBTi thin film. Furthermore, the NaBTiNb thin film showed a low leakage current density, which was 1.48 × 10?6 A/cm2 at an applied electric field of 100 kV/cm.  相似文献   

19.
In this study, we synthesized a novel polyurethane (PU) curing agent (CA) modified by the diazafluorene derivative, 9,9′‐di(4‐hydroxyphenyl)‐9‐1H‐4,5‐diazafluorene, at different hydroxyl ratios. The results of 1H‐NMR and Fourier transform infrared spectroscopy proved the structure of the fluorine derivative and the modification of CAs. Differential scanning calorimetry and dynamic mechanical analysis showed that the glass‐transition temperature of the PU increased with the addition of the diazafluorene derivative, and the PU cured in the novel CA had more stable and better damping properties under moderate‐temperature conditions (30–80 °C) than the PU cured in the N75 CA. Tan δ was maintained in a relatively lower range shift in the moderate‐temperature range. The average adhesion values of the PU coating cured in the novel CA increased. The scanning electron microscopy morphologies of the PU film and the average adhesion of the coatings showed that the PU cured in the novel CA had good mechanical properties. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46591.  相似文献   

20.
The cationic–nonionic dispersing centers with different chain lengths of poly ethylene glycol methyl ether (N‐PDEA 750, N‐PDEA 2000) were prepared from N‐diethanol amine (NDEA), isophorone diisocyanate (IPDI), and poly(ethylene glycol methyl ether) (PEO Mw = 750 and 2000), whereas aqueous cationic–nonionic polyurethane (N‐PDEA PU) with different side chain lengths were prepared by N‐PDEA 750 (or N‐PDEA 2000), 4,4‐methylene bis(isocyantocyclohexane) (H12MDI), polytetramethylene glycol (PTMG 2000), ethylene diamine (EDA), and glycolic acid (GA) as cationic–nonionic dispersing center, hard segment, soft segment, chain extender, and quarternizing agent, respectively. The thermal and mechanical properties of PU casting film were then discussed. We also used N‐methyldiethyolamine (N‐MDEA) without PEO as cationic dispersing center to synthesize aqueous cationic PU (N‐MDEA PU). The PU blends were blending N‐PDEA 750 PU and N‐MDEA PU by different weight ratios and the physical properties of casting films and coated fabric of PU and PU blends were investigated. Regarding the thermal properties, we have found out that the cationic–nonionic PU (N‐PDEA 750 PU, N‐PDEA 2000 PU) has lower Tgs, Tms, TmH, and ΔHH than N‐MDEA PU, apart from ΔHs. The N‐PDEA 2000 PU with longer side‐chain PEO has lower Tgs, higher Tms and ΔHs than N‐PDEA 750 PU. As for mechanical property, N‐PDEA PU has lower tensile strength of casting film compared with N‐MDEA PU. Regarding the comparison of side chain length of PEO, N‐PDEA 2000 PU with longer side chain has higher tensile strength than N‐PDEA 750 PU with shorter side chain length. In addition, N‐PDEA 2000 PU group that shows hard property in stress–strain curve, whereas N‐PDEA 750 PU shows soft property. The tensile strength of PU blends decreases as the content of N‐PDEA 750 PU increases. When the low‐blend ratio of N‐PDEA 750 PU (e.g., 5%), the tensile strength of casting film only shows less influence that can improve the elongation effectively. In terms of coating‐treated fabrics, cationic–nonionic PU‐coated fabrics show lower waterproof capacity (WP) than those treated by cationic PU. However, the water vapor permeability (WVP) and antiyellowing of the N‐PDEA 750 PU coated fabrics are significantly better than the one treated by cationic polyurethane. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 2963–2974, 2006  相似文献   

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