共查询到20条相似文献,搜索用时 31 毫秒
1.
Ken-ichi Kato Kaori Ito-Akita Hiroyuki Ohno 《Journal of Solid State Electrochemistry》2000,4(3):141-145
Poly(ethylene oxide) (PEO) oligomers having alkali metal thiolate groups on the chain ends (PEO
m
-S−M+) were prepared as an ion conductive matrix. The molecular weight of the PEO part (m) and the content of the thiolate groups in the molecule were changed to analyze the effect of carrier ion concentration in
the bulk. In a series of potassium salt derivatives, PEO350-SK showed the highest ionic conductivity of 6.42 × 10−5 S/cm at 50 °C. In spite of a poor degree of dissociation which was derived from the acidity of the thiolate groups, PEO
m
-SM showed quite high ionic conductivity among other PEO/salt hybrids. PEO
m
-SM had glass transition temperatures (T
g) 20 °C lower than other PEO/salt hybrids. Lowering the T
g was concluded to be effective in providing higher ionic conductivity for PEO-based polymer electrolytes.
Received: 30 April 1999 / Accepted: 20 June 1999 相似文献
2.
Novel composite polymer electrolytes based on poly(ether-urethane) network polymer and fumed silicas
X. J. Wang H. P. Zhang J. J. Kang Y. P. Wu S. B. Fang 《Journal of Solid State Electrochemistry》2007,11(1):21-26
Novel composite solid polymer electrolytes (CSPEs) and composite gel polymer electrolytes (CGPEs) have been prepared. CSPE
consists of poly(ether-urethane) network polymer (PUN), fumed silicas and LiClO4. The ionic conductivity of CSPEs can be enhanced nearly 20 times in comparison with the plain system without the addition
of fumed silicas and can be above 1×10−5 S/cm at room temperature. The effects of both kinds of fumed silicas, viz. uSiO2 with hydrophilic groups at the surface and mSiO2 with hydrophobic groups at the surface on ionic conductivity were investigated. CGPE comprising of the CSPE and LiClO4–PC solution with good mechanical strength exhibits ionic conductivity in the order of 10−3 S/cm at room temperature and above 3×10−4 S/cm at low temperature −40 °C. 相似文献
3.
H. Hatakeyama R. Kosugi T. Hatakeyama 《Journal of Thermal Analysis and Calorimetry》2008,92(2):419-424
Lignin-and molasses-based polyurethane (PU) foams with various lignin/molasses mixing ratios were prepared. The hydroxyl group
in molasses and lignin is used as the reaction site and PU foams with various isocyanate (NCO)/the hydroxyl group (OH) ratios
were obtained.
Thermal properties of PU foams were investigated by differential scanning calorimetry (DSC), thermogravimetry (TG) and thermal
conductivity measurement. Glass transition temperature (T
g) was observed depending on NCO/OH ratio in a temperature range from ca. 80 to 120°C and thermal decomposition temperature
(T
d) from ca. 280 to 295°C. Mixing ratio of molasses and lignin polyol scarcely affected the T
g and T
d. Thermal conductivity of PU foams was in a range from 0.030 to 0.040 Wm−1 K−1 depending on mixing ratio of lignin and molasses. 相似文献
4.
The thermal decomposition kinetics of polyurethane/polyethyl acrylate interpenetrating polymer networks (PU/PEA IPN) were studied by means of thermogravimetry and derivative thermogravimetry (TG-DTG), and compared with those of polyurethane (PU) and polyethyl acrylate (PEA). The decomposition temperature (T
i) of PU/PEA IPN was found to be higher thanT
i
of PEA, but lower thanT
i
of PU. Thermal decomposition kinetic parameters,n andE, estimated using Coats-Redfern method, are found for PU/PEA IPN, PU and PEA to be 1.6, 1.9 and 1.1, and 196.6, 258.6 and 139.2 kJ mol–1, respectively. The results show that PU/PEA IPN is neither a simple mixture of PU and PEA nor a copolymer of them. The mechanism of thermal decomposition of PU/PEA IPN is different from those of PU and PEA. The special network in PU/PEA IPN effectually protects weak bonds in the molecular chain of PU and PEA.We express our thanks to Dr. Yaxiong Xie and Zhiyuong Ren for their help in this work, 相似文献
5.
Mojtaba Haghighi Yazdi Pearl Lee-Sullivan 《Journal of Thermal Analysis and Calorimetry》2009,96(1):7-14
An inherent challenge with polymer blends is the difficulty in resolving the glass transition, T
g, for the smaller mass fraction component. The objective of this work was to determine the practical scanning conditions for
identifying the dual T
g’s for a 75:25 polycarbonate/acrylonitrile-butadiene-styrene (PC/ABS) blend using a thermomechanical analyzer (TMA). Scanning
rates up to 20°C min−1 using dilatometer and expansion modes were studied. Heating and cooling rates were found to affect both T
g values but the effects were not simple relationships. T
g values could either increase or decrease depending on the scanning rate applied. Higher rates resulted in large thermal lags
which opened the accuracy of measurements to question. Generally, higher rates tended to display only one T
g but the duality of T
g’s can be detected with scanning rates between 0.5 and 5°C min−1 for both modes. 相似文献
6.
Jong-Chan Lee Morton H. Litt Charles E. Rogers 《Journal of Polymer Science.Polymer Physics》1998,36(1):75-83
Gas barrier properties of alkylsulfonylmethyl-substituted poly(oxyalkylene)s are discussed. Oxygen permeability coefficients of three methylsulfonylmethyl-substituted poly(oxyalkylene)s, poly[oxy(methylsulfonylmethyl)ethylene] (MSE), poly[oxy(methylsulfonylmethyl)ethylene-co-oxyethylene] (MSEE), and poly[oxy-2,2-bis (methylsulfonylmethyl)trimethylene oxide] (MST) were measured. MSEE, which has the most flexible backbone of the three polymers, had an oxygen permeability coefficient at 30°C of 0.0036 × 10−13 cm3(STP)·cm/cm2·s·Pa higher than that of MSE, 0.0014 × 10−13 cm3(STP)·cm/cm2·s·Pa, because the former polymer's Tg was near room temperature. MST with two polar groups per repeat unit and the highest Tg showed the highest oxygen permeability, 0.013 × 10−13 cm3(STP) · cm/cm2·s·Pa, among the three polymers, probably because steric hindrance between the side chains made the chain packing inefficient. As the side chain length of poly[oxy(alkylsulfonylmethyl)ethylene] increased, Tg and density decreased and the oxygen permeability coefficients increased. The oxygen permeability coefficient of MSE at high humidity (84% relative humidity) was seven times higher than when it was dry because absorbed water lowered its Tg. At 100% relative humidity MSE equilibrated to a Tg of 15°C after 2 weeks. A 50/50 blend of MSE/MST had oxygen barrier properties better than the individual polymers (O2 permeability coefficient is 0.0007 × 10−13 cm3(STP)·cm/cm2 ·s·Pa), lower than most commercial high barrier polymers. At 100% relative humidity, it equilibrated to a Tg of 42°C, well above room temperature. These are polymer systems with high gas barrier properties under both dry and wet conditions. © 1998 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 36 : 75–83, 1998 相似文献
7.
V. N. Smirnov 《Kinetics and Catalysis》2011,52(2):166-169
The results of our experimental studies and an analysis of the published data on the rate constant for the reaction Fe + O2 = FeO + O in the forward (I) and reverse (−I) direction are reported. The data obtained in this work are described by the
expressions k
1 = 6.2 × 1014exp(−11100 K/T) cm3 mol−1 s−1 and k
−1 = 6.0 × 1013exp(−588 K/T) cm3 mol−1 s−1 (T = 1500–2500 K). The generalized expressions for the temperature dependences of these rate constants derived by combining
our results with the literature data can be presented as k
1 = 9.4 × 1014(T/1000)0.022exp(−11224 K/T) cm3 mol−1 s−1 (T = 1500–2500 K) and k
−1 = 1.8 × 1014(1000/T)0.37exp(−367 K/T) cm3 mol−1 s−1 (T = 200–2500 K). 相似文献
8.
Jian-Liang Zhou Qi-Yuan Chen Ying-Ying Gu Guang-Quan Mei Hua-Wu Yang 《Transition Metal Chemistry》2005,30(8):1036-1041
Coordination polymers {[Et4N][Ag2I3]}n (1) and [CuBr(C10H8N2S2)]n (2) were prepared by standard Schlenk techniques. Their X-ray measurements indicate that polymer (1) crystallizes in the orthorhombic space group Pnma, and polymer (2) crystallizes in the monoclinic space group P21/n. Complex (1) has a hanging ladder-like polymeric chain which can also be described as a helical chain bridged by Ag–Ag edges. Complex
(2) exhibits a monoclinic crystal system with a slightly distorted tetrahedron. The nonlinear optical (NLO) properties of (1) and (2) were investigated by using Z-scan techniques with an 8 ns pulsed laser at 532 nm. These two coordination polymers exhibit
NLO absorption and an effective self-focusing effect. The effective α2 and n2 values of cluster (1) are 3.04×10−11 m W−1 and 7.6×10−18 m2 w−1 and the effective α2 and n2 values of compound (2) are 1.08×10−11 m W−1 and 3.1×10−18 m2 w−1 when measured in CH2Cl2 solution. 相似文献
9.
Yuri M. Boiko 《Colloid and polymer science》2011,289(9):971-979
The evolution of lap-shear strength (σ) with healing temperature T
h at symmetric and asymmetric amorphous polymer−polymer interfaces formed of the samples with vitrified bulk has been investigated.
It has been found that the square root of the lap-shear strength behaves with respect to healing temperature as σ
1/2 ~ T
h both at symmetric and asymmetric interfaces. Basing on this scaling law between σ and T
h, the values of the surface glass transition temperature ( Tgsurface ) \left( {T_{\rm{g}}^{\rm{surface}}} \right) have been estimated for a number of amorphous polymers by the extrapolation of the experimental curves σ
1/2 ~ T
h for symmetric polymer−polymer interfaces and, in some cases, for asymmetric, both compatible and incompatible, polymer−polymer
interfaces, to zero strength. A significant reduction in surface glass transition temperature Tgsurface T_{\rm{g}}^{\rm{surface}} with respect to the glass transition temperature of the polymer bulk ( Tgbulk ) \left( {T_{\rm{g}}^{\rm{bulk}}} \right) , reported earlier, has been confirmed by the use of the new proposed approach. The quasi-equilibrium surface glass transition
temperature Tgsurface T_{\rm{g}}^{\rm{surface}} of amorphous polystyrene (PS) has been predicted in the framework of an Arrhenius approach using the plot “logarithm of healing
time − reciprocal surface glass transition temperature Tgsurface¢¢ T_{\rm{g}}^{\rm{surface}}\prime \prime and the activation energy of the surface alpha-relaxation of PS has been calculated. 相似文献
10.
Studies on direct-current electrical conductivity and optical properties of a new solution of processable conducting polymer
are reported. Electrical conductivity of thin films of the polymer on glass plate at room temperature was 6×10−6 S/cm. Study of conductivity with variation of temperature does not provide any definite thermal activation energy, which
is in accordance with the amorphous nature of polymer. Optical absorption data adopting the Bardeen equation showed that maximum
‘optical gap’ (E
g
) is 3.30 eV. Doping with Br2-vapor was found to be only partially effective in decreasingE
g
by 0.43 eV. The polymer was found to be quite stable under normal atmospheric conditions. Environmental stability of both
undoped and doped polymer has been discussed.
Part 2: [5] 相似文献
11.
12.
Sulata K. Sahu Manjulata Sahu Raman S. Srinivasa Thiagarajan Gnanasekaran 《Monatshefte für Chemie / Chemical Monthly》2012,97(3):1207-1214
Abstract
Heat capacities of PbCrO4(s), Pb2CrO5(s), and Pb5CrO8(s) were measured by differential scanning calorimetry. The measured heat capacities as a function of temperature are expressed as C p <PbCrO4> J K−1 mol−1 = 150.37 + 27.74 × 10−3 T − 2.80 × 106 T −2 (T = 300–750 K), C p <Pb2CrO5> J K−1 mol−1 = 194.55 + 76.09 × 10−3 T − 4.64 × 106 T −2 (T = 300–700 K), and C p <Pb5CrO8> J K−1 mol−1 = 323.35 + 184.80 × 10−3 T − 5.48 × 106 T −2 (T = 300–600 K). From the measured heat capacity data, thermodynamic functions such as enthalpy increments, entropies, and Gibbs energy functions were derived. 相似文献13.
The heat capacity of the solid indium nitride was measured, using the Calvet TG-DSC 111 differential scanning microcalorimeter
(Setaram, France), in the temperature between (314–978 K). The temperature dependence of the heat capacity can be presented
in the following form: C
p=41.400+0.499·10−3
T−135502T
−2−26169900 T
−3. 相似文献
14.
Miaoliang Huang Hongxun Yang Jihuai Wu Jianming Lin Zhang Lan Pingjiang Li Sancun Hao Peng Han Qiwei Jiang 《Journal of Sol-Gel Science and Technology》2007,42(1):65-70
Using poly(acrylonitrile-co-styrene) as polymer host, 1,2-propanediol carbonate, dimethyl carbonate and ethylene carbonate as mixture solvent, N-methyl-quinoline iodide and iodine as the source of I−/I3
−, a novel polymer gel electrolyte with ionic conductivity of 5.12 × 10−3 S· cm−1 at 25°C was prepared by sol-gel and hydrothermal methods. Based on the polymer gel electrolyte, a quasi-solid-state dye-sensitized
solar cell was fabricated. The solar cell possess better long-term stability and light-to-electrical energy conversion efficiency
of 4.04% under irradiation of 100 mW· cm−2. The influences of polymer host, solvent, N-methyl-quinoline iodide and temperature on ionic conductivity of the polymer gel electrolyte and the performance of the dye-sensitized
solar cell was discussed. 相似文献
15.
Wang Xinling Chen Jianjun Hong Ling Tang Xiaozhen 《Journal of Polymer Science.Polymer Physics》2001,39(19):2225-2230
A novel hyperbranched poly(glycidol) (HPG) was prepared and characterized. The synthesized HPG was used as a substrate of a polymer electrolyte. The ionic conductivity of a blend of HPG, polyurethane (PU), and salt was studied. The ionic conductivity of HPG/PU/LiClO4 was about 6.6 × 10?6 S · cm?1 at 20 °C and 6.3 × 10?4 S · cm?1 at 60 °C. The results indicated that HPG showed higher solubility for salt than linear polyether when both had the same [O]/[Li+] molar ratio. The main reason was that more cavities and a lower degree of chain entanglement in HPG resulted in a lower glass‐transition temperature and were beneficial for decreasing the aggregation of salt or enhancing the ionic conductivity. © 2001 John Wiley & Sons, Inc. J Polym Sci Part B: Polym Phys 39: 2225–2230, 2001 相似文献
16.
N. B. Morozova P. P. Semyannikov S. V. Sysoev V. M. Grankin I. K. Igumenov 《Journal of Thermal Analysis and Calorimetry》2000,60(2):489-495
The temperature dependency of the saturated vapor pressure of Ir(acac)3 has been measured by the method of calibrated volume (MCV), the Knudsen method, the flow transpiration method, and the membrane
method. The thermodynamic parameters of phase transition of a crystal to gas were calculated using each of these methods,
and the following values of ΔH
T
0 (kJ mol−1) and ΔS
T
0 (J mol−1K−1), respectively, were obtained: MCV: 101.59, 156.70; Knudsen: 130.54, 224.40; Flow transpiration: 129.34, 212.23; Membrane:
95.45, 149.44
Coprocessing of obtaining data (MCV, flow transportation method and Knudsen method) at temperature ranges 110−200°C as also
conducted:ΔH
T
0 =127.9±2.1 (kJ mol−1 ); ΔS
T
0 =215.2±5.0 (J mol−1 K−1 ).
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
17.
Complex formation constants were determined potentiometrically (by a ISE-H+, glass electrode) in the systems, M2+ – Lz – H+ [M2+ = (C2H5)2Sn2+, Lz = malonate, glycinate and ethylenediamine] at t = 25 ∘C and 0.1 mol-L−1≤ I/ ≤ 1 mol-L−1 in NaClaq (0.1 mol-L−1 ≤ I ≤ 0.75 mol-L−1 for the ethylenediamine system). Thermodynamic values of formation constants, at infinite dilution, are [± 95% confidence
interval, Tβpqr refer to the equilibrium, pM2+ + qLz + rH+ = MpLqHr(2+z+r)]: for malonate, log10 Tβ110 = (5.47 ± 0.10); for glycinate, log10 Tβ110 = (9.54 ± 0.08), log10 Tβ111 = (12.97 ± 0.10); and for ethylenediamine, log10 Tβ110 = (10.47 ± 0.10), log10 Tβ120 = (16.17 ± 0.12) and log10 Tβ111 = (15.46 ± 0.10). The dependence on ionic strength of the formation constants was modeled by a simple Debye–Hückel type equation
and by the SIT approach. By analyzing the stability of the species in the three different systems we found a simple additivity
rule that can be expressed by the relationship: log10 K = 6.46 nN + 3.96 nO − 0.60 (nN2+ nO2), with a mean deviation, ε(log10 K) = 0.15 (K = equilibrium constant for the interaction of the organometal cation with the unprotonated or protonated ligand, nN = number of amino groups and nO = number of carboxylic groups of the ligand(s) involved in the formation reaction of complex species). 相似文献
18.
L. P. Ogorodova M. F. Vigasina L. V. Mel’chakova 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2009,83(13):2204-2207
Thermal, IR spectroscopic, and thermochemical studies of natural brittle mica, margarite Ca1.00Na0.10Mg0.02Al3.89Fe0.013+Si2.03Ti0.01O10(OH)1.74F0.26, were performed. The enthalpy of formation of natural margarite from the elements (−6269 ± 12 kJ/mol) was determined by melt
solution calorimetry on a high-temperature heat-conducting Calvet microcalorimeter (Setaram, France). Enthalpy growth over
the temperature range 298.15–973 K was determined by the drop method. Equations for the temperature dependences of the enthalpy
and heat capacity were obtained, H°(T)−H°(298.15 K), J/mol = 435.21T + 36.46 × 10−3
T
2 + 109.91 × 105/T − 169863 and C°
p
, J/(mol K) = 435.21 + 72.92 × 10−3
T − 109.91 × 105/T
2. The experimental data were used to estimate the thermodynamic properties of margarite of the theoretical composition, CaAl2[Al2Si2O10](OH)2. 相似文献
19.
Polymer electrolyte systems were prepared for the first time by dissolution of amidomagnesium chlorides in poly(ethylene oxide),
(PEO). For the preparation, solutions of (hexamethyldisilylamido)magnesium chloride, (dimethylpyrrolyl)magnesium chloride,
(diisopropylamido)magnesium chloride, piperidinomagnesium chloride and morpholinomagnesium chloride were chosen. The composition
of these polymer electrolyte systems corresponds to the general formula R2NMgCl·P(EO)n·THF. Most work has been done with the system (hexamethyldisilylamido)magnesium chloride in PEO, (Me3Si)2NMgCl·P(EO)n·THF, with n= 3, 4, 5, or 7. The electrolytes have a soft rubber-like consistency. At 30 °C, electrical conductivities of 10−6–10−5 S/cm were found. The conductivities were measured in the temperature range 20–60 °C. Within this temperature range a linear
dependence of the logarithms of the conductivity on the inverse temperature was found and activation energies for the conducting
process of 30–60 kJ/mol were calculated. Using those polymer electrolytes with a high content of the amidomagnesium compound,
a reversible magnesium deposition takes place by cathodic reduction at potentials below −1.9 V vs. a Ag/AgCl reference electrode.
These polymer electrolytes were found to be stable against oxidation up to about −0.3 V vs. Ag/AgCl.
Electronic Publication 相似文献
20.
Hui Zhang Gui-ling Zhang Jing-yao Liu Miao Sun Bo Liu Ze-sheng Li 《Theoretical chemistry accounts》2008,119(5-6):445-451
Theoretical investigations are carried out on the reaction multi-channel CH3COCH3 + Cl (R1) and CH3 COCH3 + CH3 (R2) by means of direct dynamics methods. The minimum energy path (MEP) is obtained at the MP2/6-31 + G(d,p) level, and energetic
information is further refined at the BMC–CCSD (single-point) level. The rate constants are calculated by the improved canonical
variational transition state theory (ICVT) with the small-curvature tunneling (SCT) correction in a wide temperature range
200–3,000 K. The theoretical overall rate constants are in good agreement with the available experimental data and are found
to be k
1 = 3.08 × 10−17
T
2.03exp(−32.96/T) and k
2 = 1.61 × 10−23
T
3.53 exp(−3969.51/T) cm3molecule−1s−1.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献