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731.
This article describes several European cooperative research examples in the field of polymer composite materials. The projects, which were carried out in collaboration between industrial and academic partners, were all supported by the European Union. They deal, e.g., with (a) the manufacturing and crash testing of thermoplastic composite structures, (b) the production of thermoplastic composite preforms, and (c) the energy absorption behavior of aluminum foams, and other interesting subjects. 相似文献
732.
733.
含涂层空心球复合泡沫塑料的模量预测及讨论 总被引:3,自引:0,他引:3
利用Mori-Tanaka平均应力的概念和Eshelby等效夹杂的原理,研究了含涂层空心球复合泡沫塑料的弹性性质,从理论上导出了这类复合材料的有效模量预测公式.此外,基于这些理论公式,讨论了涂层厚度和泊松比变化对复合泡沫塑料有效模量性质的影响. 相似文献
734.
PEP与阴离子表面活性剂复配体系泡沫性能的研究 总被引:6,自引:0,他引:6
研究了PEP型非离子表面活性剂分别与十二烷基苯磺酸钠(DBS),十二烷基硫酸钠(SDS)形成复配体系的泡沫性能,讨论了浓度及配比的变化对泡沫性能的影响,结果表明起泡性和稳泡性皆随混合表面活性剂的浓度的上升而增强;在一定浓度下,随着PEP比例下降,起泡性和稳泡性也随着增大,并达到稳定值。 相似文献
735.
发展具有高催化活性和高稳定性的非Pt阳极催化剂目前仍面临着巨大的挑战. 除了设计催化剂以外,设计合适的载体对提高电催化剂性能也具有重要意义. 在这篇论文中,作者报导了一种以混合酸(HNO3+H2SO4+H3PO4+CH3COOH) 腐蚀的镍泡沫负载Pd纳米粒子作为高性能电催化剂用于碱性条件下乙醇氧化. 因具有开放孔结构、快速电解质渗透能力及快速的电荷传输性能,这些镍泡沫负载的Pd纳米粒子显示了很好的电催化活性和循环稳定性,显示了该材料在乙醇阳极氧化具有较好的应用前景. 相似文献
736.
Mohammad Ali Kamyabi Hoda Mohammadian Salma Jadali Mohsen Moharramnezhad 《Electroanalysis》2019,31(8):1484-1493
In this project, Pt/NiO?GO nanocatalyst is grown on nickel foam (NF) and, its catalytic activity towards electrochemical oxidation of methanol in acidic media is studied. The first step is devoted to the synthesis of NiO?GO support by a hydrothermal method. Then Pt nanoparticles (~34.3 nm) are electrodeposited on this supporting material. Hydrothermal and electrochemical deposition conditions are optimized. Surface of modified NF was inspected for physical characterization and Chemical composition by some techniques such as field emission scanning electron microscopy (FESEM), energy‐dispersive X‐ray spectra (EDS), and X‐ray diffraction (XRD). In the electrochemical section, the catalytic performance of Pt/NiO?GO/NF towards methanol oxidation is investigated by cyclic voltammetry and chronoamperometry measurements. The electrochemical impedance spectroscopy (EIS) is elected to deliberate charge transfer resistance on the catalyst surface. Mass activity, electrochemical surface area (ECSA) and durability of prepared catalysts are compared with commercial Pt/C. Deliberations prove the superiority of Pt/NiO?GO/NF towards methanol oxidation in acidic media. The Superior quality of synthesized nanocatalyst that is attributed to the synergetic effect of the NiO?GO support material and Pt nanoparticles, indicate that Pt/NiO?GO/NF can be successfully used as the anode in the direct methanol fuel cell (DMFC). 相似文献
737.
Wenzong Xu Rui Chen Jiaying Xu Guisong Wang Chuanming Cheng Hongyi Yan 《先进技术聚合物》2019,30(7):1738-1750
In this work, a new kind of co‐modified phenolic foam was synthesized with polyurethane prepolymer (PUP) and H3BO3 by a simple preparation method. Firstly, in order to determine the optimal amount of PUP, the effects of different PUP additions on the mechanical properties, foam microstructure, and pulverization rate of phenolic foam were investigated. Then H3BO3 was added to toughened phenolic foam, in order to reduce its fire hazard. The results showed that the mechanical properties of the PFPUP8 phenolic foam composite were the best when the PUP content was 8 wt%. It had a small and regular cell structure, and its pulverization ratio was reduced by 80% compared with that of pristine phenolic foam. Meanwhile, the flame retardant properties of PFPUP8 were improved in different degrees with an increase in the amount of H3BO3. Particularly, when the addition of H3BO3 was 10 wt%, the peak heat release rate, the total heat release, and the total smoke release values of PFPUP10B were decreased by 35.4%, 42.4%, and 45.2%, respectively, compared with those of PFPUP8. The value of the limit oxygen index was increased by 33.1%. Besides, the addition of H3BO3 had no adverse effect on the mechanical properties and pulverization ratio of PFPUP8. In addition, the specific mechanisms of toughening, flame retardant, and smoke suppression are also discussed in this paper on the basis of an investigation into the thermal properties of the toughened flame retardant foam composites by thermogravimetric analysis in N2 atmosphere. 相似文献
738.
The flame‐retardant rigid polyurethane foams (RPUFs) with dimethyl methylphosphonate (DMMP) and modified ammonium polyphosphate (MAPP) were prepared. The results showed that the limiting oxygen index (LOI) value was improved by adding DMMP into RPUF/MAPP composite; 10 wt% of DMMP addition can increase the LOI value from 24.3% to 26.0%, where the commercial application standard of RPUF is achieved. Further benefits of using DMMP/MAPP system included restraining of total heat and smoke release, improvement of thermal stability, and char yield of RPUF. The thermogravimetric analysis (TGA)‐gas chromatography‐mass spectrometer (GC‐MS) results indicated that DMMP/MAPP could continuously release PO2 and PO·free radicals in the gas phase. In addition, DMMP/MAPP exhibited the charring effect and barrier effect in the condensed phase, such bi‐flame retardant effect exerted by DMMP/MAPP resulted in the enhanced flame retardant property of RPUF. 相似文献
739.
Wanfen Pu Lin Sun Yong Pu Ying Chen 《Journal of Dispersion Science and Technology》2019,40(5):646-656
A major concern, in the foam flooding projects, is the stability of foam in the presence of oil. In this study we chose three foaming agents with different behaviors in the oil-bearing environments and examined their performance in terms of the emulsified oil and the pseudoemulsion films. The results indicate that the state of the emulsified oil or the pseudoemulsion films has a significant impact on foam stability. Two hypothesizes suggest that the role of emulsified oil played in foam stabilization can be summarized as increasing the emulsion stability and creating the viscous liquid phase, and interfacial adsorption and viscoelastic layers of pseudoemulsion films present a strong correlation with the foam stability. From the foam flooding experiments, the oil-enhanced foam is deemed to be more efficient in the oil displacement and the liquid diversion. 相似文献
740.
Roohalah Hajizadeh Ali Khavanin Mohammad Barmar Ahmad Jonidi Jafari Somayeh Farhang Dehghan 《声与振动》2019,53(5):207-222
Polyurethane foam as the most well-known absorbent materials has a
suitable absorption coefficient only within a limited frequency range. The aim
of this study was to improve the sound absorption coefficient of flexible polyurethane
(PU) foam within the range of various frequencies using clay nanoparticles,
polyacrylonitrile nanofibers, and polyvinylidene fluoride nanofibers. The
response surface method was used to determine the effect of addition of nanofi-
bers of PAN and PVDF, addition of clay nanoparticles, absorbent thickness,
and air gap on the sound absorption coefficient of flexible polyurethane foam
(PU) across different frequency ranges. The absorption coefficient of the samples
was measured using Impedance Tubes device. Nano clay at low thicknesses as
well as polyacrylonitrile nanofibers and polyvinyl fluoride nanofibers at higher
thicknesses had a greater positive effect on absorption coefficient. The mean
sound absorption coefficient in the composite with the highest absorption coeffi-
cient at middle and high frequencies was 0.798 and 0.75, respectively. In comparison
with pure polyurethane foam with the same thickness and air gap, these
values were 2.22 times at the middle frequencies and 1.47 times at high frequencies,
respectively. Surface porosity rose with increasing nano clay, but decreased
with increasing polyacrylonitrile nanofibers and polyvinyl fluoride nanofibers.
The results indicated that the absorption coefficient was elevated with increasing
the thickness and air gap. This study suggests that the use of a combination of
nanoparticles and nanofibers can enhance the acoustic properties of flexible polyurethane
foam. 相似文献