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91.
Jun Chen 《European Polymer Journal》2007,43(4):1188-1194
γ-Ray-induced polymerization of methyl methacrylate was conducted in a microemulsion stabilized by a mixture of sodium of 12-acryloxy-9-octadecenoic acid (AOA) and sodium dodecyl sulfate (SDS) with various weight ratios at room temperature. The experimental data showed that the mixture of AOA and SDS with a weight ratio 2 was an efficient surfactant system for the microemulsion containing 38.6 wt% MMA and 5.5 wt% surfactant. The effects of MMA concentration and dose rate on the polymerization kinetics and particle size are discussed. 相似文献
92.
93.
Inorganic-organic hybrids have been synthesized by incorporation of the inorganic component of Ti(OC2H5)4 into the organic polymer of ethyl cellulose. The inorganic-organic hybrids did not dissolve in toluene used as a solvent for the starting materials. The ethanol was formed as a by-product of the alcoholysis condensation reaction between Ti(OC2H5)4 and ethyl cellulose. These results suggest that ethoxy groups of Ti(OC2H5)4 react with hydroxy groups of ethyl cellulose to form cross-linking bonds of –O–Ti–O–. The reaction of Ti(OC2H5)4 with ethyl cellulose was further investigated by Fourier transform infrared (FT-IR) spectroscopy. The FT-IR spectroscopic experiments revealed that the Ti–O bond state of Ti(OC2H5)4 was changed by refluxing a toluene solution of Ti(OC2H5)4 with ethyl cellulose. The inorganic-organic hybrids have an interesting dielectric property; their dielectric constant is higher than that of ethyl cellulose and that of a simple mixture of TiO2 and ethyl cellulose. 相似文献
94.
消臭抗菌纤维素纤维的制备、结构和性能 总被引:2,自引:0,他引:2
采用一种制备消臭、抗菌纤维素纤维的新方法,即先将纤维素纤维用多元羧酸进行化学修饰,然后在铜溶液中处理,生成铜螯合纤维素纤维,用红外光谱、电子自旋波谱表征了该纤维的配位结构,消臭和抗菌实验结果显示,这种功能性纤维对硫化氢,氢气、三甲胺的消臭率分别达到100%,92.1%和80.4%,对金黄色葡萄球菌,大肠杆菌和白色念珠菌的抑菌率分别为79.14%,93.59%和82.50%,用X射线衍射,电子自旋波谱分析了该纤维吸附硫化氢,氨气、三甲胺的机理。 相似文献
96.
Two-step preparation for catalyst-free biodiesel fuel production 总被引:10,自引:0,他引:10
Biodiesel fuel was prepared by a two-step reaction: hydrolysis and methyl esterification. Hydrolysis was carried out at a
subcritical state of water to obtain fatty acids from triglycerides of rapeseed oil, while the methyl esterification of the
hydrolyzed products of triglycerides was treated near the supercritical methanol condition to achieve fatty acid methyl esters.
Consequently, the two-step preparation was found to convert rapessed oil to fatty acid methyl esters in considerably shorter
reaction time and milder reaction condition than the direct supercritical methanol treatment. The optimum reaction condition
in this two-step preparation was 270°C and 20 min for hydrolysis and methyl esterification, respectively. Variables affecting
the yields in hydrolysis and methyl esterification are discussed. 相似文献
97.
Helical poly(3-methyl-4-vinylpyridine) (P3M4VP)/amino acid complexes have been prepared via acid-base reaction of the achiral polymer with D and L amino acids: alanine, leucine, valine, serine and phenylalanine. The circular dichroism (CD) spectra of P3M4VP/D- and L-alanine complexes in CH(3)OH/H(2)O show opposing (near mirror image) Cotton effect signals at 278.4, 274.8 and 270.8 nm, indicating the formation of enantiomeric secondary structures. The formation of the enantiomeric structures is supported by observed [alpha](D)(25) values of -3.0 and +3.0 for the P3M4VP/D-alanine and P3M4VP/L-alanine complexes, respectively. The preparation of helical P3M4VP/amino acid complexes has been carried out in CH(3)OH and H(2)O at pH 1.8 and 2.7. The intensities of the Cotton effect signals were good. For example, for the P3M4VP/L-alanine complexes in CH(3)OH/H(2)O and H(2)O (pH 1.8), the second Cotton effect signal around 275-277 nm show [theta;] values of 49 980 and 79 210 deg . cm(2) . dmol(-1), respectively. The formation of the helical secondary structure is rapid. The acid-base reaction between P3M4VP and L-alanine in CH(3)OH/H(2)O, in 10 min, show a CD spectrum with Cotton effect signals at 274 and 272 nm with [theta] values of 27,000 deg . cm(2) . dmol(-1) and -36,000 deg . cm(2) . dmol(-1), respectively. P3M4VP permits ready conformational reorientation on complexation with amino acids, but once the helical P3M4VP/amino acid complexes are formed, it is stable at room temperature. P3M4VP is not compatible with HeLa ovarian cancer cells, but the helical P3M4VP/amino acid complexes are compatible with HeLa cells. The complexes minimally interfere with the adhesion and growth of HeLa cells on complex surfaces. Helical poly(3-methyl-4-vinylpyridine)/D- and L-alanine complexes support the attachment and growth of HeLa cells. The micrographs shows HeLa cells after three days: left panel: on P3M4VP/L-alanine complex; right panel: on P3M4VP/D-alanine complex. 相似文献
98.
Various types of sodium cellulose sulfate (SCS), dissolved in a 1M LiCl solution, were investigated by alternating current (AC)polarography. The SCS samples differed in the degree of substitution (DS), thedistribution of substituents within the anhydroglucose unit (AGU), and alongthechain, due to the method of synthesis. The goal was to study theelectrosorptionbehavior, characterized by the shape of the desorption wave in the polarogram,as a function of the chemical structure of the SCS samples. The shape of thedesorption wave reflects domains of different substitution. A superimpositionofparameters like DS and pattern of substitution on the electrosorption behaviorwas observed. The AC polarography method described can be used as a tool todistinguish between an even or uneven distribution of substituents along thecellulose chain. 相似文献
99.
100.
Thomas F. Brodasky 《Journal of separation science》1978,1(5):239-244
Two new acyltetramic acids related to streptolydigin have been isolated from fermentations of Streptomyces lydicus. The principal members of this complex were resolved by TLC on silica gel. However, the methods of detection, permanganate spray or bioautography, were not suitable for both crude fermentation broths and purified extracts. Gas chromatography is unsuitable for the detection of either underivatized or silylated streptolydigins. High performance liquid chromatography (HPLC) particularly on triethylaminoethyl cellulose is rapid and sensitive and is the method of choice for the analysis of both crude and purified samples. Using high performance liquid chromatography, two components were detected in the complex, which are not observed using any of the other chromatographic procedures. 相似文献