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101.
In the present work, the ohmic resistance of an integrated planar-SOFC (IP-SOFC) has been evaluated by developing a model
whose equations have been solved numerically through an FEM method. The model allows to estimate the distribution of voltage
and current density in the cell. A comparison between simulated and experimental data of area specific resistance is reported,
which shows satisfactory agreement. The mathematical model has also been used to carry out some parametric studies for optimisation
purposes. Indeed, a reduction in cell pitch length and an increase in electrode thickness are predicted to lead to a reduction
in ohmic losses in IP-SOFCs. 相似文献
102.
Branched polyacrylonitrile (PAN) was prepared through a self‐condensing vinyl copolymerization of acrylonitrile and 2‐(2‐bromopropionyloxy)ethyl acrylate (BPEA). The branched architecture of the product was confirmed by NMR spectra and the average degree of branching (DB ) was estimated. Through a comparison of the intrinsic viscosity of the product with that of its linear analogue, the contraction factor g′ was calculated. It was found that the viscosity of the branched PAN was obviously lower that that of linear PAN. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008 相似文献
103.
Ching‐Nan Chuang Liang Chao Ying‐Jie Huang Tar‐Hwa Hsieh Hung‐Yi Chuang Shu‐Chi Lin Ko‐Shan Ho 《应用聚合物科学杂志》2008,107(6):3917-3924
The synthesis of a p‐toluidine/formaldehyde (PTF) resin was performed, and the effects of the molar ratio of the individual monomers and the polymerization conditions on the structure of the PTF resin were studied. Fourier transform infrared and 13C‐NMR spectra were used to characterize the PTF. Wide‐angle X‐ray diffraction patterns revealed the crystalline structures of various PTFs. Polarized optical microscopy revealed that the molar ratio of the monomers had a strong effect on the crystalline morphologies. A longer polymerization time turned out a polymer with a higher intrinsic viscosity and molecular weight, which led to differences in the proton conductivity. All of the PTFs showed a higher proton conductivity than a commercial Nafion membrane at 90–100°C and 0% relative humidity. The proton conductivity of the PTF series could be improved by sulfonation with sulfuric acid and could be maintained after blending with polyurethane. Pure methanol could be used as a fuel source because of the insolubility and nonwetting properties of PTF in methanol to increase the output current density for a PTF membrane electrode assembly. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2008 相似文献
104.
A. Mounir EL Sayed A. Yamauchi N. A. Darwish A. A. Abd EL‐Mageed S. F. Halim 《应用聚合物科学杂志》2008,109(5):2988-2993
The charged mosaic polymer membrane (CMM) without reinforcement and the composite charged mosaic polymer membrane (CCMM) with reinforcement were investigated in terms of salt and water transport (permeability). The composite charged mosaic polymer membrane (CCMM) with reinforcement showed a unique transport behavior such as preferential material transport Lp and ω. Water permeability coefficient, Lp and salt permeability coefficient, ω were estimated by taking account of active layer thickness of composite polymer gel. The Lp and ω values of CCMM with reinforcement were larger than those of CMM without reinforcement. On the other hand, the reflection coefficient of CCMM, σ, showed negative value, which suggested preferential material transport to solvent transport. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008 相似文献
105.
We present the synthesis and characterization of poly(N,N-dimethylaminoethyl methacrylate) (PDMAEMA) cylindrical brushes, their pH responsiveness, and the corresponding quaternized analog, poly{[2-(methacryloyloxy)ethyl] trimethylammonium iodide} (PMETAI) brushes. PDMAEMA brushes were prepared by atom transfer radical polymerization (ATRP) using the grafting-from strategy. Initiating efficiencies of the ATRP processes were determined by cleaving the side-chains and gel permeation chromatography (GPC) analysis. Due to the slow initiation and steric hindrance, the initiating efficiency is only around 50%. The PDMAEMA brushes show worm-like structures and pH responsiveness, as proven by dynamic light scattering (DLS), atomic force microscopy (AFM), and cryogenic transmission electron microscopy (cryo-TEM) measurements. Strong cationic polyelectrolyte PMETAI brushes were produced by quaternization of the PDMAEMA brushes. AFM and cryo-TEM images showed similar worm-like morphologies for the PMETAI brushes. The PMETAI brushes collapsed in solution with high concentration of monovalent salt, as proven by DLS and AFM results. 相似文献
106.
Defeng Wu Yisheng Zhang Lanfeng Wu Lifeng Jin Ming Zhang Weidong Zhou Changhao Yan 《应用聚合物科学杂志》2008,108(3):1934-1941
Polyarylene ether nitriles (PEN)/thermotropic liquid crystalline polymer (TLCP) blend was prepared via melt mixing. The immiscible phase morphologies, linear and nonlinear, as well as transient viscoelastic properties of the blend were studied using SEM, rheometer, and DMA. The linear dynamic viscoelastic behavior of the blend shows temperature dependence due to further evolution of the immiscible morphology and, as a result, the principle of time‐temperature superposition (TTS) is invalid. In the steady shear flow, the discrete TLCP phase is difficult to be broken up because of the high viscosity ratio of the blend systems, while is easy to be coarsened and followed by elongation, and finally, to form fibrous morphology at high TLCP content and high shear level. During this morphological evolution process, the transient stress response presents step increase and nonzero residual relaxation behavior, leading to increase of the dynamic viscoelastic responses after steady preshear. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008 相似文献
107.
Investigation of the thermal, mechanical, and fracture properties of alumina-epoxy composites 总被引:1,自引:0,他引:1
A combination of dynamic shear rheology, thermomechanical analysis (TMA), scanning electron microscopy (SEM), Near-Edge X-ray Absorption Fine Structure (NEXAFS), and fracture toughness testing was utilized to characterize the thermal, mechanical, chemical, and fracture properties of alumina (α-Al2O3)-filled epoxy resins as a function of average filler size, size distribution, particle shape, loading, and epoxy crosslink density. In general the cured properties of the filled composites were robust. Small changes in particle size, shape, and size distribution had little impact on the final properties. Resin crosslink density and filler loading were the most critical variables, causing changes in all properties. However, most applications could likely tolerate small changes in these variables also. SEM and NEXAFS characterization of the fracture surfaces revealed that the fracture occurs at the filler interface and the interfacial epoxy composition is similar to the bulk resin, indicating a weak epoxy-alumina interaction. These results are critical for implementation of particulate-filled polymer composites in practical applications because relaxed material specifications and handling procedures can be incorporated in production environments to improve efficiency. 相似文献
108.
109.
Veysel T. Yilmaz Evrim Senel Canan Kazak 《Journal of Inorganic and Organometallic Polymers and Materials》2008,18(3):407-413
The reaction of [Cu(sac)2(H2O)4] · 2H2O with 2-methylpyrazine (mpyz) leads two complexes, concomitant crystallization of a mononuclear complex [Cu(sac)2(mpyz)(H2O)2] (1) and a polymeric complex [Cu(sac)2(μ-mpyz)]n (2). Both complexes have been characterized by elemental analyses, magnetic measurements, FT-IR and ESR, TG-DTA and single-crystal
X-ray diffraction analyses. Single-crystal X-ray analyses show that complex 1 consists of discrete molecules in which the copper(II) ions exhibits a square-pyramidal coordination geometry. The individual
molecules of 1 are connected into a hydrogen-bonded chain structure, which is further assembled to form a three-dimensional network by π–π stacking interactions.
Complex 2 is an 1D coordination polymer in which copper(II) centers are bridged by the mpyz ligand. The chains are further assembled
to form two-dimensional frameworks by π–π and C–H···π stacking interactions. 相似文献
110.
高聚物PVP的制备及应用 总被引:1,自引:0,他引:1
在相纸涂层中加入聚乙烯基吡咯烷酮,它能与涂层中的荧光增白剂紧密结合,从而使增白剂在冲显加工过程中不易流失,保证了相纸的白度,较好地适应了简单快捷的纯海波定影法。 相似文献