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聚对苯二甲酸丁二酯纤维在超临界二氧化碳介质中的染色研究 总被引:4,自引:0,他引:4
用超临界二氧化碳作介质,在40~120℃,10~30MPa条件下使用分散染料对聚对苯二甲酸丁二酯(PBT)纤维进行染色试验,并测定了3种分散染料在超临界二氧化碳介质中的溶解度。研究了染色温度、压力、时间及染料结构对染料上染量的影响,考察了染料溶解度与染料上染量的关系。试验表明,在80℃,20MPa下,染色30min,PBT纤维能得到良好的染色效果,上染量达4.01mg/g(分散红60)、2.43mg/g(分散黄23)、11.19mg/g(分散蓝79)。 相似文献
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Absorption of a series of low molecular weight solutes into polyurethane was investigated in supercritical carbon dioxide with different conditions. The effect on the amount of solutes absorbed in polyurethane due to these factors such as pressure, temperature, absorption time, decompression time, the character of solutes, and the amount of cosolvent was examined by a gravimetric method. The absorption mechanism was discussed. The desorption of solutes in polyurethane showed a dependence on the logarithm of time. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 77: 3162–3168, 2000 相似文献
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Truc T. Ngo Jonathan McCarney James S. Brown Michael J. Lazzaroni Karl Counts Charles L. Liotta Charles A. Eckert 《应用聚合物科学杂志》2003,88(2):522-530
The hydrophilicity of polymers can be improved through surface modification, traditionally done with conventional organic solvents, but these may cause the deterioration of polymer bulk properties due to irreversible polymer swelling. However, supercritical carbon dioxide (scCO2) not only swells the polymer reversibly, but also acts as a convenient transport medium for monomeric solutes, which may be subsequently polymerized. Thus we are able to modify the polymer surface without affecting its bulk strength and durability. Here we report scCO2 surface modification of polybutadiene using ultraviolet‐visible (UV/Vis) and Fourier transform infrared (FTIR) spectroscopy. Monomers such as 3‐vinylbenzoic acid and crotonic acid are used to study the effects of pressure, solute structure, and reaction mechanism on the diffusion rates and partitioning of monomers between the fluid phase and the polymer. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 522–530, 2003 相似文献
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Tássio Benazzi Selma Calgaroto Clarissa Dalla Rosa J. Vladimir Oliveira Marcio A. Mazutti 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》2013,88(9):1766-1768
This work evaluates the hydrolysis of sugarcane bagasse using supercritical carbon dioxide to obtain fermentable sugars in a single‐step process. The effects of temperature, pressure, despressurization rate, moisture content and reaction time on the amount of fermentable sugars released were assessed. Results obtained showed the feasibility of adopting the present procedure since it produced about 287 g of fermentable sugars per kg of dry bagasse, which corresponds to 60% yield on the basis of total cellulose. Such a result is very attractive from an industrial viewpoint because there is no use of toxic solvent, solvent removal is completed (no residues), and the method has very low water consumption since the process is a solid–gas reaction. © 2012 Society of Chemical Industry 相似文献
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Lei Ye Keiichi Yoshimatsu Dorota Kolodziej Jos Da Cruz Francisco Estera S. Dey 《应用聚合物科学杂志》2006,102(3):2863-2867
Molecularly imprinted polymer nanoparticles were prepared in supercritical carbon dioxide using a noncovalent imprinting approach. In the present work, propranolol was used as a model template, methacrylic acid as a functional monomer, and divinylbenzene as a crosslinker. Under a high dilution condition, the heterogeneous polymerization resulted in discrete crosslinked polymer nanoparticles. Compared with the nonimprinted polymers, the imprinted nanoparticles displayed much higher propranolol uptake in a low polarity organic solvent. The use of a single enantiomer (S)‐propranolol as the template clearly demonstrated that the imprinted binding sites are chiral‐selective, with a cross‐reactivity towards (R)‐propranolol of less than 5%. The overall binding performance of the imprinted nanoparticles was comparable to imprinted polymers prepared in conventional organic solvents. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 2863–2867, 2006 相似文献
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利用超临界二氧化碳流体脱硫再生丁基橡胶 总被引:2,自引:0,他引:2
研究了硫黄硫化的丁基橡胶在超临界二氧化碳流体辅助下的脱硫降解行为,讨论了脱硫工艺的条件,并通过凝胶渗透色谱、核磁共振、差示扫描量热等对丁基再生胶的结构和性能进行了考察。结果表明,在二氧化碳的超临界状态下丁基橡胶的脱硫降解更加充分。脱硫的最佳工艺条件为: 反应温度180 ℃,反应压力14. 1 MPa,脱硫剂二苯基二硫的用量为橡胶质量的8%; 经过120 min 脱硫反应后丁基再生胶中溶胶的质量分数为98. 5%。在有热降解和脱硫剂参与的脱硫反应的共同影响下,丁基再生胶中溶胶的数均分子量降至原胶的40%左右; 再生胶主链上接枝了部分脱硫剂的苯环; 硫化和脱硫过程中在接枝于主链上的极性基团的影响下,再生胶中溶胶主链双键氢的振动峰几乎消失,但再生胶的玻璃化转变温度并没有明显变化。 相似文献
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Solubility of fatty acids in supercritical carbon dioxide 总被引:1,自引:0,他引:1
P. Maheshwari Z. L. Nikolov T. M. White R. Hartel 《Journal of the American Oil Chemists' Society》1992,69(11):1069-1076
The solubilities of lauric, linoleic, myristic, oleic, palmitic and stearic acid in supercritical carbon dioxide (SC-CO2) at different pressures and temperatures were measured. The solubility values obtained in this work were compared with previously
published data, and possible causes for observed discrepancies were discussed. The solubilities of the six fatty acids were
modeled by Chrastil’s equation, and estimated model parameters were used to plot the solubility isotherms of fatty acids at
313, 323 and 333°K (40, 50 and 60°C) as a function of SC-CO2 density. The comparison of solubility isotherms of fatty acids and vegetable oil suggests that separation of fatty acids
from triglycerides might be possible by using SC-CO2 at densities less than 700 kg/m3. From the effect of temperature on fatty-acid and vegetable-oil solubility, it seems that the extraction yield could be increased
without sacrificing the selectivity of SC-CO2 for fatty acids by choosing a higher operating temperature. The data also suggest that fractionation of certain fatty acids
might be possible by manipulating the processing conditions. Given the values of the constants, Chrastil’s equation could
serve as a guideline for choosing appropriate processing conditions and predicting the effect of pressure and temperature
of SC-CO2 on solute solubility. 相似文献
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The transesterification of soybean oil with glycerol, 1,2-propanediol, and methanol by an immobilized lipase in flowing supercritical
carbon dioxide for the synthesis of monoglycerides is described. A lipase from Candida antarctica was used to catalyze the reaction of soybean oil with glycerol, 1,2-propanediol, ethylene glycol, and methanol. Reactions
were performed in supercritical carbon dioxide at a density of 0.72 g/L and at a flow rate of 6 μL/min (expanded gas). The
substrates were added at flows ranging from 2.5 to 100 μL/min. Monoglycerides were obtained at up to 87 wt%, and fatty acid
methyl esters at nearly 100 wt%. The reactivity of the alcohols paralleled the solubility of the substrate in liquid carbon
dioxide. Glycerol has the slowest reaction rate, only 2% of that of methanol. 相似文献
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C. Tsitsimpikou H. Stamatis V. Sereti H. Daflos F. N. Kolisis 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》1998,71(4):309-314
The acylation of glucose with lauric acid in a reaction catalysed by two Candida lipases and a Mucor miehei lipase in supercritical carbon dioxide (SCCO2) was investigated. A linear dependence of the reaction rate on enzyme concentration was observed. Studies on the effect of temperature on enzyme activity showed that Candida antarctica lipase remains stable at temperatures as high as 70°C. Non-immobilised Candida rugosa lipase was found to have a temperature optimum at 60°C. The acylation reaction rate depended on the initial water activity of both substrates and enzyme; the optimum was 0·75 for Candida antarctica lipase, 0·53 for Candida rugosa lipase, and between 0·3 and 0·5 for Mucor miehei lipase. Candida rugosa lipase was most active at a molar ratio of sugar: acyl donor of 1: 3, while the optimum ratio was found to increase to 1: 6 when the reaction was catalysed by Candida antarctica and Mucor miehei lipases. © 1998 SCI 相似文献
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A. Molero G mez E. Mart nez de la Ossa 《Journal of the American Oil Chemists' Society》2000,77(9):969-974
The extraction of wheat germ oil by liquid and supercritical CO2 is described from the point of view of both operative method and pretreatment of raw material. The best conditions for wheat
germ oil extraction are: pressure, 150 bar; temperature, 40°C; and solvent flow rate, 1.5 L/min at standard temperature and
pressure. The yields and fatty acid compositions obtained are very similar to those resulting from the conventional extraction
process using hexane as solvent (8.0 wt%), although a higher-quality oil is obtained by using CO2 as solvent (free fatty acids, 12.4%; tocopherol content, 416.7 mg tocopherol/g wheat germ oil). These factors lead to the
conclusion that the extraction process using CO2 could be economically competitive with the conventional process, since it considerably simplifies the oil refinement stages
and completely eliminates the solvent distillation stage, which are the most costly processing steps in terms of energy consumption. 相似文献
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K. Sawada D. Terada T. Yamaoka S. Kitamura T. Fujisato 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》2008,83(6):943-949
BACKGROUND: The objective of this work was to decellularize artificial tissue without using surfactant solutions. For this purpose, supercritical carbon dioxide was used as the extraction medium. RESULTS: Supercritical carbon dioxide containing a small amount of entrainer was a suitable medium to extract both cell nuclei and cell membranes from artificial tissue. Under gentle extraction conditions (15 MPa, 37 °C), cell nuclei were satisfactorily extracted from tissue within 1 h. In contrast, the efficiency of phospholipid removal depended strongly on the transfer rate of carbon dioxide in the interior of the tissue. Mechanical strength of tissue was not decreased even with prolonged treatment. CONCLUSION: Acellular artificial tissues could be prepared quickly by treatment with a carbon dioxide/entrainer system. The prepared acellular tissue could be obtained in absolutely dry condition. This is advantageous from the viewpoint of long‐term preservation without putrefaction and contamination. Copyright © 2008 Society of Chemical Industry 相似文献
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The copolymerization of styrene (St) and maleic anhydride (MA) was carried out in supercritical carbon dioxide (SC CO2). It was found that St and MA are easy to copolymerize in SC CO2 and the conversion can reach 97%, and that very fine and dry powders are obtained. The products were characterized using Fourier transform infrared spectroscopy (FTIR), gel permeation chromatography (GPC), scanning electron microscopy (SEM), differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA). GPC data showed that the molecular weight of the copolymer reach 3.62 × 104 g mol?1. Scanning electron microphotographs showed the minimum particle size of the product is about 200 nm. DSC measurements indicated that the glass transition temperature (Tg) of the copolymer increases with increasing the MA content in the copolymer. TGA curve showed that the copolymers were decomposed at about 350°C. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007 相似文献
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Enzymatic alcoholysis of cod liver oil, with an immobilized lipase, was carried out in supercritical carbon dioxide. The enzyme
was catalytically active under the experimental conditions used. The reaction medium was investigated to preferentially extract
ethyl esters, synthesized during the course of the experiment, from the unconverted cod liver oil substrate and side-products.
The effect of pressure changes on the amount of tri-, di-, and monoglycerides and ethyl esters, present in both the extract
and the remaining lipid residue, was determined. Furthermore, the fatty acid compositions of the lipid classes were analyzed,
and the relative amounts of both eicosapentaenoic acid and docosahexaenoic acid to palmitic acid were determined. The results
show that it is possible to preferentially extract the synthesized ethyl esters at low pressures. The extract collected at
9 MPa contained 64 g ethyl esters/100 g extract, while the total amount of all other lipid classes detected was 19 g/100 g
extract. As the pressure was increased, the relative amount of the other lipid classes detected in the extract, especially
triglycerides, was enhanced. The relative amounts of both eicosapentaenoic acid and docosahexaenoic acid to palmitic acid
increased for some lipid classes in the extract. This increase was most pronounced for the monoglyceride lipid class. The
integration of biocatalysis and product fractionation, applied in this study, suggests that the potential for biocatalysis
in industrial processes is considerably wider than had been thought. 相似文献
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We report on an efficient and environmentally friendly means to modify surface properties of polymer films supported for nanoparticles. Ultrathin polystyrene (PS) films (<300 Å), in which inorganic nanoparticles were embedded, were exposed to supercritical carbon dioxide (scCO2). The swollen structure was then preserved by quickly evaporating CO2. X-ray reflectivity (XR) results showed that this procedure produced polymeric nanocomposite films with a low-density region of about 150Å at the polymer/air interface. The formation of the low-density layer was independent of the nature of the particles, indicating that the surface modification through exposure to scCO2 may be a universal phenomenon regardless of a choice of nanoparticles. 相似文献