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聚乙烯塑料在连续超临界水反应器中的油化研究 总被引:1,自引:1,他引:1
在连续超临界水(SCW)反应器中考察了反应温度、停留时间和反应压力对聚乙烯(PE)降解油化的影响。实验结果表明,在120s、25MPa下,从500℃提高到550℃,液体收率呈现先升后降的趋势,在530℃达到最大值(79%);在520℃、25MPa下,随停留时间的延长,PE裂解程度加深,产物轻质化程度提高,导致液体收率降低,停留240s时,气体收率达到43%;反应压力对产物收率的影响较小,气、液产物中烯/烷比随反应压力的增加而增大。 相似文献
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选择450、500、550、600、650、700℃等不同裂解温度,保持基本一致的进样量(60士1pg),采用连续升温和分别升温的方法,对聚乙烯及阻燃聚乙烯进行裂解气相色谱(PyGC)分析,比较其性能的差异以及加有不同量阻燃剂的PE的裂解色谱性能.结果表明Si02含量不同的阻燃聚乙烯有较明显的阻燃性能,其中SiO2添加量为6%时阻燃效果最好,PyGC的分析结果与锥形量热仪(CONE)的实验结果相一致. 相似文献
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讨论了超高分子量聚乙烯(UHMW-PE)的熔融一次拉伸和二次拉伸的晶体结构和力学性能.利用WAXD和SAXD测定了拉伸片的晶体取向因子和极图,晶粒尺寸,晶体畸变,长周期等晶体结构.用DSC和VES测定热性能和动态力学性能.应力-应变实验测定拉伸片的杨氏模量,断裂强度和伸长.这些实验结果说明UHMW-PE经二次拉伸能产生正交晶系的伸直链晶体.二次拉伸片由折叠链片晶和伸直链晶体两元结构组成.二次拉伸片的杨氏模量比一次拉伸片有大幅度提高.二次拉伸片的晶体结构和力学性能是在一次拉伸的基础上形成的. 相似文献
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In this study, concentration of celestite particles was investigated by using oil agglomeration. For this purpose, effects of operating parameters were investigated, and zeta potential measurements and Fourier transform infrared spectrophotometry (FTIR) analyses have also been carried out. In the experiments, effects of operating parameters such as pH, stirring speed, amount of Na oleate as a anionic type collector and kerosene as a bridging liquid, solid ratio, agglomeration time, collector stirring time, conditioning time, and amount of EDTA were investigated to obtain optimum conditions. Zeta potential measurements were carried out for various pH values and amounts of Na oleate. FTIR analyses were investigated to determine the adsorption type of Na oleate on celestite surface. By evaluation of the experimental results, optimum oil agglomeration conditions of celestite were determined as follows: pH 7, stirring speed 1500 rpm, amount of kerosene 100 l/t, amount of Na oleate 10 kg/t, solid ratio 5 wt%, conditioning time 5 min, collector stirring time 1 min, agglomeration time 5 min, and amount of EDTA 1.0 kg/t. In the optimum conditions, celestite was concentrated with recovery of 89.47 wt%. 相似文献
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超临界水中聚乙烯油化的研究 总被引:9,自引:2,他引:9
采用125mL间歇式高压釜反应器,在超临界水条件下考察了反应温度、反应时间、水/聚乙烯比和水填充率对聚乙烯降解油化的影响。实验结果表明,聚乙烯在超临界水中迅速降解,油收率可达90%以上;随温度从450℃提高到480℃,油收率从91.4%下降到61.7%,气体收率从1.9%提高到27.7%;在450 ℃反应时间从1 min延长到30 min时,油收率略有下降,油品中C7-11组分所占比例增大一倍。水/聚乙烯比和水填充率的增加在一定程度上对聚乙烯的降解起抑制作用。 相似文献
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Waki Sakatsuji Takashi Konishi Yoshihisa Miyamoto 《Journal of Thermal Analysis and Calorimetry》2013,113(3):1129-1134
The effects of the thermal history on enthalpy relaxation in polymethylmethacrylate (PMMA) have been studied by differential scanning calorimetry (DSC). The temperature dependence of specific heat capacity in the liquid and glassy states, that of relaxation time and the exponent of the Kohlrausch–Williams–Watts function have been obtained by the measurement of the response of heat flux to the sinusoidal temperature variation. The phenomenological model equation as an extension of linear rheology has been applied to enthalpy relaxation. The evolution of entropy under a given thermal history same as the experiment has been calculated and compared with the DSC results. The calculated results reproduce two peaks of specific heat capacity at lower and higher temperatures in the glass transition region: the former is characteristic of PMMA and the latter is observed in typical glassy polymers. 相似文献
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S. A. Dauengauer O. G. Utkina G. S. Popova Yu. N. Sazanov 《Journal of Thermal Analysis and Calorimetry》1987,32(1):311-314
When the DTA of polystyrene is carried out in air in a platinum sample holder, an anomalously high endothermic effect is observed. This effect was found to be related to gas-phase catalytic styrene oxidation occurring on the surface of both operating and reference platinum sample holders. Methodological recommendations are given concerning the DTA procedure for organic substances, making it possible to avoid this type of anomaly. 相似文献
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A mathematical model for thermal self-ignition of a two-phase system with a homogeneous bimolecular exothermic reaction in a batch reactor is proposed. The influence of the volumetric ratio of phases and the specific surface area of exchange interface on the parameters of thermal ignition of the system was studied. The kinetic dependences of reactant concentrations and the reactor heating dynamics were investigated. 相似文献
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We demonstrate that peptides derived from alpha-amino acids may be prepared in a micro reactor. The peptides were prepared in 20 min with quantitative conversion, compared to batch reactions which require prolonged reaction times. We illustrate that by using dilute reagent concentrations and short reaction times, less racemisation is observed in micro reactions than in bulk reactions. 相似文献
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G. Keller F. Lavigne C. Loisel M. Ollivon C. Bourgaux 《Journal of Thermal Analysis and Calorimetry》1996,47(5):1545-1565
The thermal behavior of three ural fats (displaying very different composition), cocoa butter (CB)2, lard, and a stearin obtained from anhydrous milk-fat (AMF) fractionation, were studied by both DSC and X-ray diffraction as a function of temperature (XRDT). To perform temperature explorations between –30C and +80C, at rates identical to those used for DSC and ranging from 0.1 K min–1 to 10 K min–1, a new set of X-ray sample-holders, temperature-controlled by Peltier effect, has been developed. It is shown that the three more stable polymorphic forms of CB were easily characterized by either X-ray diffraction or DSC, and existence of two -3L forms was confirmed. On the contrary, the more complex polymorphism of lard and AMF required combined examination by DSC and XRDT and the brightness of the synchrotron source for studies at the highest heating rates. Quantitative analysis of the long spacings of XRDT recordings is invaluable for interpretation of thermal events. For instance, it was found that the simultaneous formation of two polymorphic forms, of apparent long spacing of 34 and 42 å, at the onset of lard crystallization might explain the difficulty of its fractionation.Special thanks to Courtney P. Mudd (NIH, Bethesda) for his pertinent advice on the mounting and use of thermoelectric devices. The study of lard crystallization was initiated by Valerie Portalier and suggested by Jean-Luc Vendeuvre of CTSCCV (Maisons-Alfort). For the AMF part of this study, stearin was fractionated by ADRIA Normandie, while characterization of its thermal properties was performed as part of a research program funded by ARILAIT Recherches and the French Ministry of Research and Technology. 相似文献
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The supramolecular interaction of rubidate (chemically 2,3-naphthalenedicarboxylic acid, 1,4-dihydroxy-diethyl ester) and beta-cyclodextrin (beta-CD) has been studied by spectrofluorimetry. The influence of temperature on the supramolecular system has also been investigated and the thermodynamic parameters were calculated. The results show that beta-CD reacts with rubidate to form a 1:1 host-guest complex with an apparent association constant of 566+/-23 l mol(-1). It was also demonstrated that the thermodynamics of beta-CD-rubidate complex displayed a compensatory enthalpy-entropy relationship. Based on the significant enhancement of the fluorescence intensity of rubidate produced through complex formation, a spectrofluorimetric method for the determination of rubidate in bulk aqueous solution in the presence of beta-CD was developed. The linear relationship between the fluorescence intensity and rubidate concentration was obtained in the range from 2.7x10(-2) to 3.0 mug ml(-1), with a correlation coefficient of 0.9988. The detection limit was 8.2 ng ml(-1) and the relative standard deviation was 1.6%. There was no interference from the excipients normally used in tablet formulations. The application of the present method to the determination of rubidate in tablets gave satisfactory results and was compared with the reference method. 相似文献
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K. Pathmanathan Jean-yves Cavaill G. P. Johari 《Journal of Polymer Science.Polymer Physics》1989,27(7):1519-1527
The dielectric permittivity and loss of Bisphenol-A-polycarbonate (PC) was measured over the frequency range 100 Hz to 200 kHz and temperature range 77–383 K. One sub-Tg relaxation peak is observed which rapidly broadens with a decrease in temperature. This is attributed to a progressive separation of the γ and β peaks, which at high temperatures are merged to form one peak of high strength. The strength of the sub-Tg relaxations decreases on physical aging of PC but is increased if the sample is quenched from a temperature above its Tg. Slowly cooled PC has a lower strength of its sub-Tg relaxation than a quenched specimen. The thermal history of PC affects the magnitude of its sub-Tg relaxation. 相似文献