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71.
聚砜—聚醚砜共混膜相容性及凝胶特性研究   总被引:8,自引:1,他引:7  
研究了聚砜(PSF)与聚醚砜(PES)共混膜的相容性及其凝胶特性.首先,通过计算PSF-PES共混体系的混合热,从理论上预测该共混体系相容性,并用反相气相色谱法(IGC)测定相互作用参数.研究PSF-PES共混体系相容性与组成的关系;通过粘度测定研究了共混制膜液的溶混性;探讨了共混制膜液的凝胶特性.研究结果表明,PSF-PES共混体系为部分相容体系,且其溶混性与组成有关,共混可明显改变制膜液的凝胶特性.  相似文献   
72.
改性栲胶在缝洞型碳酸盐岩油藏中的堵水实验研究   总被引:1,自引:0,他引:1  
根据塔河油田奥陶系缝洞型碳酸盐岩油藏条件,对耐高温改性栲胶堵剂在矿物组分相近的人造缝洞型岩心中的堵水机理进行了实验研究。在油井水层出水压力高于油层压力或者产油层裂缝大于出水层裂缝情况下,采用笼统注入方式堵水须进行暂堵处理,以封住产油层,使堵剂主剂选择性进入水层。改性栲胶堵剂可在水层中形成均匀的较强凝胶封堵带,而在油层中形成的是残余油与凝胶混合物,易被突破和形成流动通道;另外,改性栲胶凝胶具有极性,与碳酸盐岩表面结合比较稳固。因此,改性栲胶堵剂对水层的封堵能力更强。由于塔河油田地层水矿化度非常高,预冲洗既能隔离注入堵剂与地层水,又能降低溶胶聚沉,有利于提高改性栲胶凝胶对碳酸盐岩油藏出水层的封堵能力。  相似文献   
73.
A series of novel polyarylethersulfone (AB) n block copolymers with different segment lengths have been synthesized by nucleophilic solution polycondensation of phenoxide‐terminated and fluorine‐terminated oligomers; random copolymers have been prepared over the whole composition ranges. The structures of the resultant copolymers have been confirmed by FTIR, 13C NMR spectra and differential scanning calorimetry (DSC). Compared with two homopolymers and random copolymers, the block copolymers of this study possess excellent thermal stability (5% thermal decomposition under nitrogen atmosphere above 500 °C) and high glass transition temperatures, and have a wide melt‐processing temperature range. They may become a new class of mouldable high performance thermoplastics. © 2001 Society of Chemical Industry  相似文献   
74.
A hybrid simulation was carried out using discrete variational (DV) Xα molecular orbital and molecular dynamics methods to examine the storage of hydrogen in metal nanoparticles. The calculation load was light and therefore could be performed quickly on a generic personal computer. The simulation investigates the electronic states of hydrogen on Pd and Ti nanoparticles. The hydrogen dissociation behavior on the metal surface was reproduced, and the calculated bonding orbitals of Pd and hydrogen are consistent with other reports. The diffusion coefficient of hydrogen inside the metal displays the same temperature dependence as the theoretical results. This simplified calculation, which produces results in agreement with experimental/theoretical values, could lead to improved simulation methods for hydrogen storage materials.  相似文献   
75.
Novel membranes based on sulfonated poly (phenylene oxide) (SPPO) was developed. SPPO membranes in the hydrogen form were converted to metal ion forms. The effect of exchange with metal ions including monovalent (Li+, Na+, K+), divalent (Mg2+, Ba2+, Ca2+) and trivalent (Al3+) ions was investigated in terms of permeation rate and permeation rate ratios for CO2 and CH4 gases. Both dense homogeneous membranes and thin‐film composite (TFC) membranes were studied for their gas separation characteristics. The effect of membrane preparation conditions and operating parameters on the membrane performance were also investigated. The selectivity of the TFC membrane increased as the cationic charge density increased as a result of electrostatic cross‐linking. TFC membrane of very high selectivity was achieved by coating a thin layer of SPPO‐Mg on a PES substrate. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 76: 735–742, 2000  相似文献   
76.
A new, milder sulfonation process was used to produce ion‐exchange polymers from a commercial polysulfone (PSU). Membranes obtained from the sulfonated polysulfone are potential substitutes for perfluorosulfonic acid membranes used now in polymer electrolyte fuel cells. Sulfonation levels from 20 to 50% were easily achieved by varying the content of the sulfonating agent and the reaction time. Ion‐exchange capacities from 0.5 to 1.2 mmol SO3H/g polymer were found via elemental analysis and titration. Proton conductivities between 10−6 and 10−2 S cm−1 were measured at room temperature. An increase in intrinsic viscosity with increasing sulfonation degree confirms that the sulfonation process helps to preserve the polymer chain from degradation. Thermal analysis of the sulfonated polysulfone (SPSU) samples reveals higher glass transition temperatures and lower decomposition temperatures with respect to the unsulfonated sample (PSU). Amorphous structures for both PSU and SPSU membranes were detected by X‐ray diffraction analysis and differential scanning calorimetry. Preliminary tests in fuel cells have shown encouraging results in terms of cell performance. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 77: 1250–1257, 2000  相似文献   
77.
The physical and chemical properties of polystyrene grafted and sulfonated polytetrafluoroethylene (PTFE‐graft‐PSSA) membranes prepared by radiation‐induced grafting of styrene onto commercial PTFE films using simultaneous irradiation technique followed by a sulfonation reaction are evaluated. The investigated properties include water uptake, ion exchange capacity, hydration number and ionic conductivity. All properties are correlated with the amount of grafted polystyrene (degree of grafting). The thermal stability of the membrane evaluated by thermal gravimetric analysis (TGA) is compared with that of original and grafted PTFE films. The membrane surface structural properties are analysed by electron spectroscopy for chemical analysis (ESCA). Membranes having degrees of grafting of 18 % and above show a good combination of physical and chemical properties that allow them to be proposed for use as proton conducting membranes, provided that they have sufficient chemical and mechanical stability. © 2000 Society of Chemical Industry  相似文献   
78.
-中国能源正在逐渐"绿色化",原因有以下四方面。第一,中国的经济模式正在快速转化,过去三十年的世界工厂正在转变为以高科技经济为主。第二,中国投资于替代能源(太阳能光伏、风能等)的势头非常凶猛,曾经这些投资是用在传统的能源行业(如煤炭、石油等)。  相似文献   
79.
Toughened mixtures containing 15 wt % polyethersulfone were made with diglycicdyl ether of bisphenol-A resin and 4,4′-diaminodiphenylmethane curing agent, with amine/epoxy group stoichiometric ratios varying from 0.6 to 1.5. Fracture behavior of the modified mixtures has been investigated as a function of the stoichiometry in the matrix. Morphology has been analyzed by transmission and scanning electron microscopy. The increase of amine content in the matrix results in a further increased fracture toughness. This behavior has been related to the changes on the ductility of the matrix upon stoichiometric ratio, but also to the changes on microstructural features of the modified mixtures as stoichiometric amine/epoxy group ratio increased. These morphological changes have been interpreted in terms of spinodal decomposition during curing of the epoxy matrix. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 69: 183–191, 1998  相似文献   
80.
Aqueous dispersions of lightly sulfonated polystyrene were prepared. The effects of initial polymer concentration, neutralizer, ionic content, solvent property, and store time on the stability, the particle size, and the distribution of the dispersed phase for the resultant oil-in-water emulsions were studied. It was found that the particle size varied with the variation of polymer concentration and increased with increase in the store time. The effects of the neutralizer and the mixed solvents on the particle size were also significant. The particle size increased with increase in volume of the counterion. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 70: 2075–2079, 1998  相似文献   
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