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191.
Ionic liquid, an organic molten salt, has efficient flame-retardant performance. Few researchers have attempted to study its flame-retardant mechanism. Moreover, thermal stability and pyrolysis products have a great impact on the flame retardancy. Therefore, this paper focused on the phosphate ionic liquid of 1-butyl-3-methylimidazolium dibutyl phosphate ([Bmim][DBP]) and analyzed its thermal decomposition products and characteristics. The major bond energies of [Bmim][DBP] were calculated using B3LYP/6–311++G(d,p)//M06–2X/6–311++G(d,p) level. The experimental results show that the pyrolysis products were as followed: alkane or alkene with a carbon chain length of 1–4; imidazole and its derivatives; esters. Furthermore, Gas chromatography-mass spectrometer and Fourier transform infrared spectrometer were utilized to measure the gaseous products and solid phase products of [Bmim][DBP], which were obtained during thermogravimetric analysis. The results of theoretical and experimental analysis were highly consistent. Finally, the possible flame-retardant mechanism of [Bmim][DBP] was proposed. 相似文献
192.
In order to evaluate the flame-retardant capacity of KHCO3 and ABC on the ignition of PMMA dust layer accumulation on hot surfaces, the ignition time and critical heating temperature of PMMA/KHCO3 and PMMA/ABC dust layer were experimentally investigated. The thermal stability of the mixed dust, the condensed phase products and gas phase products of the mixed dust combustion were analyzed to reveal the flame-retardant mechanism. The ignition time of 30 μm PMMA was obviously longer than that of 5 μm PMMA, and the critical heating temperature was close to that of 5 μm PMMA. KHCO3 and ABC could greatly extend the ignition time of the PMMA dust layer and increase the critical heating temperature of the dust layer. ABC was more effective than KHCO3. The decomposition of KHCO3 and ABC absorbed the heat and inhibits the pyrolysis of PMMA. The HPO3 and P2O5 generated by the decomposition of ABC would cover the surface of PMMA aggregates or particles and act as a physical barrier. The main light combustible gas produced by PMMA pyrolysis were CO and C2H4. The CO2 generated during the decomposition of KHCO3 could dilute the combustible gas in the ambient to inhibit the combustion of PMMA. 相似文献
193.
Saeed Kazemi Najafi 《Waste management (New York, N.Y.)》2013,33(9):1898-1905
The use of recycled and waste thermoplastics has been recently considered for producing wood plastic composites (WPCs). They have great potential for WPCs manufacturing according to results of some limited researches. This paper presents a detailed review about some essential properties of waste and recycled plastics, important for WPCs production, and of research published on the effect of recycled plastics on the physical and mechanical properties of WPCs. 相似文献
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Trends in waste plastics and recycling 总被引:2,自引:0,他引:2
Tadao Kasakura Reiji Noda Kenichi Hashiudo 《Journal of Material Cycles and Waste Management》1999,1(1):33-37
Zero emission is an ambitious project aimed at the conversion of the conventional top-down or one-directional flow type production
systems of modern society to those of a recycling type. The basic idea underlying this project is to understand in detail
the material flow mechanism in a particular segment of society and to evaluate the transformability of the hitherto one-directional
types of process into recycling types. The authors, members of the Zero-Emission Research Group of Japan, are investigating
the material flow of plastics in Japan. The present work describes the features of this project, as well as the results obtained
so far.
Received: May 28, 1998 / Accepted: October 16, 1998 相似文献
196.
Explosions are the main types of accidents causing casualties in underground coal mines. Research on the mechanisms of gas explosions is needed as a basis for the development of techniques and strategies for explosion prevention, suppression, and mitigation. The prevention of loss in explosion accidents and inquiries into their causes require understanding of the explosion process of methane in air. Because of the high cost and safety issues in full scale experiments, the experiments with small scale ducts have become a key alternative approach. Whether the experimental results at small scales agree with those at full scales needs to be investigated to validate the significance of the experimental results at small scale. Numerical simulation was used to obtain the explosion characteristics of a methane-air mixture in a gallery or duct. If the grid size is too fine in the numerical simulation for a methane-air explosion it is difficult to calculate using the present computer resource. If the grid size is too coarse, the considerable error may result. The effect of grid size on results of calculation depends on the scenario being investigated. The effect of grid sizes on simulation accuracy was analyzed in this work. The overpressure and temperature distributions and the flame propagation for the deflagration of methane-air mixtures in a gallery or duct were obtained by the AutoReaGas code at three different scales. The geometry of investigated objects and the grids in the calculation domain were similar in the three cases. The calculated overpressures vary with the scale. The calculated temperatures do not vary with the scale for the three cases. 相似文献
197.
Pyrolysis is considered as possible technique to thermally convert waste plastics into chemicals and energy. Literature on experimental findings is extensive, although experiments are mostly performed in a dynamic heating mode, using thermogravimetric analysis (TGA) and at low values of the heating rate (mostly below 30 K/min). The present research differs from literature through the application of far higher heating rates, up to 120 K/min. The use of these dynamic results to define the reaction kinetics necessitates the selection of an appropriate reaction mechanism, and 21 models have been proposed in literature considering the rate limiting step being diffusion, nucleation or the reaction itself.The current research studied the cracking of PET and PS by TGA at different heating rates (temperature ramps). Results were used to check the validity of the proposed mechanisms. Several conclusions are drawn: (i) to obtain fair results, the heating ramp should exceed a minimum value, calculated at 30 K/min for PET and 80 K/min for PS; (ii) application of the majority of the models to experimental findings demonstrated that they do not meet fundamental kinetic considerations and are questionable in their use; and (iii) simple models, with reaction order 1 or 2, provide similar results of the reaction activation energy.A further comparison with literature data for dynamic and isothermal experiments confirms the validity of these selected models. Since TGA results are obtained on a limited amount of sample, with results being a strong function of the applied heating rate, the authors believe that isothermal experiments, preferably on a large scale both towards equipment and/or sample size, are to be preferred. 相似文献
198.
利用共沉淀法合成了镁铝双氢氧化物(MgAl-LDH),采用熔融共混的方法,制备了含Mgal—LDH片层的无卤阻燃EVA纳米复合材料,通过多种表征手段分析研究了MgAl-LDH对无卤阻燃EVA(乙烯-醋酸乙烯酯共聚物)的协效阻燃效果。扫描电镜(SEM)和透射电镜(TEM)的结果表明LDH的片层能够促进阻燃剂在EVA基体中的分散;锥形量热仪(Conecalorimetry)燃烧测试表明协效阻燃EVA的热释放速率相对于纯阻燃EVA显著降低,其他主要燃烧参数也有同样的变化趋势,说明MgAl-LDH具有良好的协效阻燃作用。材料的燃烧残余物的形貌分析表明,LDH协效阻燃EVA在燃烧过程中能形成致密而连续的保护层,有效阻隔材料在燃烧过程中气体挥发物的扩散和与燃烧环境间能量的交换,提高燃烧残留量,降低材料的火灾危险性。 相似文献
199.
200.