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LIU QingMing BAI ChunHua JIANG Li DAI WenXi & NIU Fang State Key Lab of Explosion Science Technology Beijing Institute of Technology Beijing China 《中国科学:物理学 力学 天文学(英文版)》2011,(3)
The deflagration-to-detonation transitions (DDTs) for clouds of spherical aluminum dust (SAD) mixed with air or epoxypropane mist (EPM) and air were investigated in a 29.6-m-long experimental tube of 199 mm in diameter. The clouds formed through the injection of SAD and SAD/liquid epoxypropane samples into the experimental tube. Explosions of the SAD/air mixture were initiated using a 7-m-long EPM/air cloud explosion ignited by a 40-J electric spark. Explosions in SAD/EPM/air clouds were initiated using a 1... 相似文献
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Acrylate and methacrylate monomers absorbent acrylate foams were prepared based on the method of high internal phase emulsion (HIPE). The influence of reaction conditions on liquid absorption by acrylate foams was studied. The reaction conditions included monomer ratio, cross-linker amount, initiator amount, emulsifier amount, emulsion concentration, emulsification temperature, and the curing time. The reaction conditions were determined to achieve the best liquid absorption by acrylate foams. Acrylate foams were analyzed with Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The results showed that when the monomer ratio was 9:1, cross-linking agent was 30% of monomer amount, initiator amount was 4% of the reactants amount, emulsifier amount was 8% of the reactants amount, the ratio of aqueous phase to oil phase was 32:1, emulsification temperature was 75°C, and curing time was 1.5 h, we could prepare the acrylate foam material with the best liquid absorption. Reaction of monomer and cross-linking agent was confirmed by FTIR analysis. The pore sizes of acrylate foam were between 1 μm and 8 μm according to SEM analysis. This material was very suitable to absorb aqueous fluids. 相似文献
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M. Thirumal Dipak Khastgir Nikhil K Singha B. S. Manjunath Y. P. Naik 《高分子科学杂志,A辑:纯化学与应用化学》2013,50(7):704-712
Water blown rigid polyurethane foams (PUF) with organoclay/organically modified nanoclay (ONC) were prepared and their properties such as density, mechanical, morphological, insulation, thermal and flame retardant properties were studied. In this investigation, the ONC content was varied from 1 to 10 parts per hundred of polyol (php) by weight. It was observed that the compressive strength of ONC filled PUF increased up to 3 php of ONC loading and then it decreased. Wide angle X-ray diffraction and transmission electron microscopy studies indicated the exfoliated dispersion of ONC in PUF. The thermal conductivity of ONC filled PUF decreases up to 5 php and then increases. The glass transition temperature (Tg) of PUF decreases on loading of ONC. The TGA analysis shows that there is slight increase in degradation temperature with increase in ONC loading. The flame retardant properties (LOI and flame spread rate) are improved slightly on addition (3 php) of ONC filled PUF. 相似文献
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Pyrrole was polymerized on the surface of titanium foam using FeCl3 as oxidant and the as-synthesized product could be directly used as electrode for supercapacitor. The globular polypyrrole (PPy) particles were firmly loaded on the substrate with high density. The morphology study of PPy film is observed in SEM images, the XRD, FTIR and UV–vis spectra reveal the structure and crystalline of PPy nanoparticles. The electrochemical properties of PPy modified electrode are investigated by cyclic voltammetry (CV), galvanostatic charge/discharge (GCD) and cycle life techniques. The electrochemical measurements showed such a PPy–Ti electrode had a wide working potential window, a high specific capacitance of 855 F g−1 and excellent cycle stability at a discharge current density of 1 A g−1. 相似文献
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Char-forming property of PU rigid foams, which can be assessed by char residue (%) when PU is burned at certain temperature, was studied by TG and DTG. The results showed that pure PU rigid foam had low char residue of only 17%, while 33% of char residue was achieved when PU rigid foam was modified by adding 8 wt% of 1-oxo-2,6,7-trioxa-1-phosphabicyclo[2,2,2] octane (PEPA), which is a caged bicyclic phosphate. The experiment results of FTIR and XPS showed that the PEPA modified PU rigid foam could be dehydrogenated and dehydrated at temperature between 380 and 450 °C, resulting in the increase of char residue of PU rigid foam. Further study also revealed that the addition of CaCO3 nanoparticles could enhance the char stability when the PEPA modified PU rigid foam was being burned. The mechanism was investigated and it was found that the enhanced char stability could be attributed to the limited permeation of oxygen caused by the formation of calcium phosphate and calcium pyrophosphate by the reaction of PEPA and CaCO3 at high temperature, which were covered on or buried in the char layer. 相似文献
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Lin Sun Peng Wei Yu-Chuan Zhang Dan Zeng Meng-Yang Shi 《Journal of Dispersion Science and Technology》2013,34(12):1693-1703
Xanthan enhanced foam (XGF) is a newly developed chemical agent for enhanced oil recovery in high-temperature and high-salinity reservoirs. In this paper, laboratory experiments were performed to characterize the morphology and foam properties of XGF, to study its performance under different temperature and different salinity conditions, respectively. Based on simulate reservoir formation conditions of Xidaliya field, a series of research on XGF were conducted. The experimental results showed that the scanning electron microscopy of XGF reflected a more viscoelastic and stable nature of the foam system. High temperature had a great adverse impact upon the stability of XGF, and the increase of salinity in the solution helped to improve the stability of foam. The foam stability increased remarkably when XG4 is added, and an increase in ambient pressure made enhancement of foam stability became more noticeable. In the presence of crude oil, Xanthan could enhance the stability of emulsions and was more favorable to stabilize foam. XG4 enhanced foam had dramatic properties for mobility controlling and oil displacement in the porous media. 相似文献