共查询到19条相似文献,搜索用时 46 毫秒
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芳香聚酰亚胺气体分离膜 总被引:7,自引:0,他引:7
芳香聚酰亚胺一直在电子、复合材料及粘接剂等领域广泛地应用。最近,聚酰亚胺膜已用于气体的分离过程。这是因为芳香聚酰亚胺是具有高玻璃化温度的玻璃态聚合物,它对小分子比大分子有更大的选择透过性,高选择性是与玻璃态聚合物的僵硬主链,对不同尺寸的分子提供筛分作用相连系的。新开发的芳香聚酰亚胺膜是用联苯四甲酸二酐与芳香二胺缩聚制备的聚酰亚胺溶液制造的。这种中空纤维状的膜是由一个多孔结构支撑的一个很薄的外表面组成的。它可通过聚合物溶液采用干——湿法过程纺丝而成,经溶剂交换干燥,外层的致密部分由计算可知厚度低于0.1μm。它对H_2与CO、CH_4.N_2及其它气体的分离有高度的选择性。由于它具有聚酰亚胺特有的耐高温性能,所以可以在很广的气体加工条件下使用。这种膜对水蒸气有很高的透过性,因而也可用于有机蒸气的脱水,或空气干燥。此膜对水蒸气的透过速度为乙醇的100~200倍。30%的乙醇水溶液,经一次膜分离,浓度可提高到99%。空气干燥系统可产出达到-50℃露点的空气。 相似文献
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等离子体聚合制备气体分离膜研究概况 总被引:2,自引:0,他引:2
本文叙述了近年来等离子体聚合技术制备气体分离膜,主要是富氧膜的研究进展。着重介绍等离子体聚合制备复合膜的类型及结构、气体透过特性、等离子体反应参数对复合膜气体透过性的影响。 相似文献
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聚酰亚胺气体分离膜的进展 总被引:9,自引:0,他引:9
本文叙述了近年来聚酰亚胺气体分离膜的发展概况。讨论了聚合物结构、共聚改性、交联改性和成膜历史对聚酰亚胺透气性能的影响。脂环族聚酰亚胺和六氟二酐(6FDA)型聚酰亚胺兼具有高透气性和高透气选择性,是一类具有发展前途的气体分离膜材料。 相似文献
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Nandula D. Wanasekara LaShanda T. J. Korley 《Journal of polymer science. Part A, Polymer chemistry》2013,51(7):463-467
New bio-derived strategies have been recently explored in the design of polymer nanocomposites, particularly in the area of responsive materials, which offer pathways toward tailored interfacial adhesion, responsive interactions and controlled dispersion. In this Feature article, we discuss: (1) precise control of dispersion via self-assembly driven approaches in responsive mechanics, (2) inherent and strong interfacial adhesion in single polymer composites, and (3) percolating, electrospun nanofiber networks as filler elements in adaptable composites. © 2013 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2013 相似文献
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Dr. Tetsuro Kusamoto Shun Kimura Yasuyo Ogino Chie Ohde Prof. Dr. Hiroshi Nishihara 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(49):17725-17733
The open‐shell luminescent (3,5‐dichloro‐4‐pyridyl)bis(2,4,6‐trichlorophenyl)methyl (PyBTM) radical contains a nitrogen atom that behaves as a stimulus‐responsive site. Chemical modification at this nitrogen atom, such as coordination of B(C6F5)3 or methylation, shifts the emission maximum to the low‐energy region and increases the reduction potential. The emission colour may be regulated by the reversible Lewis acid–base reaction between B(C6F5)3 and PyBTM. Comparison of the optical and electrochemical properties of the radicals with the electronic structures calculated by density functional theory has indicated that the chemical modification decreased the energy level of the β‐singly occupied molecular orbital, a key orbital in determining the optical and electrochemical properties of such systems. 相似文献
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Summary: Temperature-induced and solvent composition-induced phase separation in solutions of poly(N-isopropylmethacrylamide) (PIPMAm) and other thermoresponsive polymers as studied by NMR and infrared (IR) spectroscopy is discussed. The fraction p of phase-separated units (units with significantly reduced mobility) and subsequently, e.g., thermodynamic parameters characterizing the coil-globule phase transition induced by temperature, were determined from reduced integrated intensities in high-resolution 1H NMR spectra. This approach can be especially useful in investigations of phase separation in solutions of binary polymer systems. Information on behaviour of water during temperature-induced phase transition was obtained from measurements of 1H NMR relaxation times of HDO molecules. NMR and IR spectroscopy were used to investigate PIPMAm solutions in water/ethanol (D2O/EtOH) mixtures where the phase separation can be induced by solvent composition (cononsolvency). Some differences in globular-like structures induced by temperature and solvent composition were revealed by these methods. 相似文献
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Extensive computer simulations of multicomponent ion exchange processes in fixed beds are reported. The simulations are based on the local equilibrium theory developed by Helfferich and Klein. The simulations illustrate through computer graphics how the various ions separate and migrate in a column. Detailed concentration profiles as a function of time are shown for cyclic chromatographic operations such as elution, displacement, and selective displacement processes. The simulations elucidate the main features of the interference phenomena as a result of solute competition for the sorbent sites. These simulations also provide important guidelines for designing bulk separation processes, for example, the strategies of recovery, the choices of cyclic operations, feed size, presaturant, eluant, and displacer. 相似文献