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111.
Dhruba Jyoti Sarkar Jitendra Kumar N. A. Shakil Totan Adak A. C. Watterson 《高分子科学杂志,A辑:纯化学与应用化学》2013,50(6):455-465
Twelve amphiphilic polymers were synthesized using poly(ethylene glycols) (PEGs) of different molecular weights, viz. 1000, 2000 and 4000 as hydrophilic block and linkers namely azelaic acid, sebacic acid, dimethyl isophthalate acid and dimethyl terephthalate as hydrophobic block in the presence of catalyst Conc. H2SO4. Synthesized polymers were characterized by using 1H-NMR, 13C-NMR and IR spectroscopy. Micellar sizes of the polymers were determined using Dynamic Light Scattering (DLS) which ranged from 51.6–174 nm for aliphatic polymers and 135.5–371 nm for aromatic polymers. Transmission Electron Microscope (TEM) results confirm the findings of DLS. Critical Micelle Concentrations (CMC) of the synthesized polymers were determined using electrical conductivity meter which ranged from 95 to 130 mg L?1 for aliphatic polymers and 420–1500 mg L?1 for aromatic polymers. 相似文献
112.
Il'yas S. Nizamov Gulnara T. Gabdullina Ilnar D. Nizamov Yevgeniy N. Nikitin Lyubov A. Al'metkina Rafael A. Cherkasov 《Phosphorus, sulfur, and silicon and the related elements》2013,188(4):732-742
A method of synthesizing arylbisdithiophosphonic acids was developed by the reaction of 2,4-diaryl 1,3,2,4-dithiadiphosphetane-2,4-disulfides with tri(ethylene glycol) and 1,4-butandiol in anhydrous benzene suspension under mild conditions. The arylbisdithiophosphonic acids thus obtained were transformed into the corresponding diammonium salts. New bis(triorganylgermyl), stannyl and plumbyl, and cyclic diphenylsilyl and diphenylplumbyl derivatives of arylbisdithiophosphonic acids were prepared from the reactions of diammonium salts of the corresponding acids with triorganylchlorogermane, chlorostannane, chloroplumbane, diphenyldichlorosilane, and diphenyl dichloroplumbane. 相似文献
113.
López-Sánchez M Domínguez-Vidal A Ayora-Cañada MJ Molina-Díaz A 《Analytica chimica acta》2008,620(1-2):113-119
A direct and fast method for determination of the adulterant diethylene glycol (DEG) in toothpaste and gel dentifrices combining attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy with partial least squares (PLS) regression has been proposed. Considering the high heterogeneity of dentifrices available in the market, the possibility of reducing the number of calibration samples for PLS was evaluated. Similar prediction performance was achieved by both employing a large calibration set of 20 dentifrices spiked with different amounts of DEG and a reduced calibration set of seven ones selected by means of hierarchical cluster analysis (HCA). The feasibility of using the simple calibration model to predict DEG adulteration in a wide variety of unknown dentifrice samples increases the applicability of the proposed method. With this approach, DEG was quantified with a root mean squared error of prediction value of 1.1% for a validation set of 40 different dentifrices containing DEG in the range 0–16% (w:w). 相似文献
114.
Influence of transesterification reactions on the miscibility and thermal properties of poly(butylene/diethylene succinate) copolymers 总被引:1,自引:0,他引:1
Poly(butylene/diethylene succinate) block copolymers (PBSPDGS), prepared by reactive blending of the parent homopolymers (PBS and PDGS) in the presence of Ti(OBu)4, were analyzed by 1H-NMR, TGA and DSC, in order to investigate the effects of the transesterification reactions on the molecular structure and thermal properties. 1H-NMR analysis evidenced the formation of copolymers whose degree of randomness increases with the mixing time. The thermal analysis of the melt-quenched samples showed that the melting peak, due to the crystalline phase of PBS, tends to disappear with increasing mixing time and therefore with decreasing the block length in the copolymers. As concern miscibility, a single homogeneous amorphous phase always occurred, independently on block length. Nevertheless, a phase separation, due to the tendency of the PBS blocks to crystallize, was evidenced in the copolymers with long butylene succinate sequences. The results obtained indicated that the block size had a fundamental role in determining the crystallizability and, therefore, phase behavior of the block copolymers. 相似文献
115.
Two new approaches for the accurate prediction of densities of the commonly used glycol solutions in the gasprocessing industry are presented in the article. The first approach is based on developing a simple-to-use polynomial correlation for an appropriate prediction of density of glycol solutions as a function of temperature and weight percent of glycols in water, where the obtained results show very good agreement with the reported experimental data. The second approach, however, is based on the artificial neural networks (ANN) methodology, wherein the results demonstrate the ability of the introduced method to predict reasonably accurate densities of glycols under operating conditions. Comparisons of the two novel approaches indicated that the simple-to-use correlation appears to be superior owing to its simplicity and clear numerical background, wherein the relevant coefficients can be retuned if new and more accurate data are available in the future. The average deviation of the new proposed polynomial correlation results from reported data is 0.64 kg/m^3 whereas the average deviation of artificial neural networks (ANN) methodology from reported data is 1.1 kg/m^3. 相似文献
116.
《印度化学会志》2023,100(5):100976
Cyclodextrins (CDs) are cyclic oligosaccharides made up of d-glucose units connected by 1,4-glucosidic linkages. β-CD is a cyclical starch derivative containing seven glucopyranose units. β-CD derivatives have characteristic property of larger surface area, robust mechanical strength, high surface to volume ratio, electrical and optical properties for analyte determination, good dispersion, easy removal of the template, surface modification, functionalization and handling capacity. In this work, an attempt is made to prepare succinyl-β-CD-acrylamide (S-β-CD-AA) copolymer and β-CD-malic anhydride (β-CD-MAH) copolymer. For the synthesis of S-β-CD-AA, S-β-CD derivative is prepared and further, acrylamide (AA) along with cross-linker undergoes free radical copolymerization for the formation of gel like product. The degree of succinylation (DS) of β-CD derivative is estimated. S-β-CD-AA copolymer showed potential swelling, and deswelling characteristic. Another copolymer is prepared from β-CD malic anhydride derivative. Further, the derivative is treated with cellulose and ethylene diamine tetra acetate (EDTA) to form β-CD-MAH copolymer. The two derivatives are characterized by several techniques. Thermal stability of these copolymers is estimated with the help of thermogravimetric analysis. The basic characterization of the presence of functional groups is done using UV–visible spectroscopy, and infrared spectroscopy. The elemental analysis helped to estimate C, H, N, S in the synthesized compounds. The surface morphology characterization is done with the help of scanning electron microscopy. X-ray diffraction analysis helped in determination of crystal structure of β-CD-MAH. β-CD derivatives prepared may be potential candidate to prepare inclusion complex, in drug delivery, drug loading and several similar applications. 相似文献