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61.
This paper describes a new method to prepare graft copolymers, such as polyethylene‐g‐polystyrene (PE‐g‐PS), with a relatively well‐controlled reaction mechanism. The chemistry involves a transformation process from the metallocene copolymerization of ethylene and m,p‐methylstyrene (m,p‐MS) to nitroxide‐mediated “living” free radical polymerization (LRFP) of styrene. The metallocene catalysis produces ethylene‐co‐m,p‐methylstyrene (EMS) random copolymers. Next, 1‐hydroxyl‐2,2,6,6‐tetramethylpiperidine (HO‐TEMPO) was synthesized by the reduction of TEMPO with sodium ascorbate. The macroinitiator (EMS‐TEMPO) was synthesized with the bromination reaction of EMS, and the following nucleofilic reaction with this functional nitroxyl compound. The resulting macroinitiator (EMS‐TEMPO) for LRFP was then heated in the presence of styrene to form graft copolymer. DSC, 1H‐NMR, FTIR spectroscopy were employed to investigate the structure of the polymers. The results of Molau test showed that PE‐g‐PS could be a potential good compatilizer. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
62.
Elham Tabrizian Ali Amoozadeh Salman Rahmani Mehdi Salehi Maciej Kubicki 《Research on Chemical Intermediates》2016,42(2):531-544
A new and economical synthesis of α, α′-bis(substituted-benzylidene)cycloalkanones has been achieved by the reaction of cycloalkanones with different aromatic aldehydes using nano-TiO2/acetic acid as a catalyst in ethanol under reflux conditions with excellent yields. Five new products and three new single crystal structures are reported. 相似文献
63.
Shahnaz Sargazi Ramazan Mirzaei Mashaallah Rahmani Mahdi Mohammadi Abdolali Khammari Masoome Sheikh 《Journal of Analytical Chemistry》2017,72(5):557-561
Di(2-ethylhexyl) phthalate (DEHP) is used as plasticizer in polyvinylchloride (PVC) plastics. Its metabolites and the parent phthalates are considered toxic. As the DEHP plasticizers are not chemically bound to PVC, they can migrate, evaporate or be leached into indoor air and atmosphere, foodstuff, and other materials. We have reported a novel, easy and available analytical method for the determination of DEHP and its metabolite, mono(2-ethylhexyl) phthalate (MEHP) in human urine samples by the in-syringe dispersive liquid–liquid microextraction method coupled with gas chromatography with flame ionization detector. The limits of detection and precision (RSD) were 2.5 μg/L and 1.4% for DEHP and 1.1 μg/L and 3.0% for MEHP, respectively. This method could be utilized for routine monitoring of the trace DEHP and MEHP in urine of human exposure to plasticizers. 相似文献
64.
Robabeh Baharfar Zahra Rahmani Mojtaba Mohseni Razieh Azimi 《Natural product research》2015,29(22):2145-2148
This study was designed to examine the total phenolic and flavonoid contents, radical scavenging and antibacterial activity of the ethanolic extracts from leaves, berries and stems of Hedera pastuchovii Woron. ex Grossh. The berry extract, which contained the highest phenolic and flavonoid compounds, showed an appreciable DPPH√ scavenging ability in comparison with leaf and stem extracts. The various extracts exhibited moderate to good activity against both Gram-negative and Gram-positive bacteria, and the effectiveness of leaf extract was higher for all tested bacteria. 相似文献
65.
A new furanodihydrobenzoxanthone, artomandin (1), together with three other flavonoid derivatives, artoindonesianin C, artonol B, and artochamin A, as well as β-sitosterol were isolated from the stem bark of Artocarpus kemando. The structures of these compounds were determined on the basis of spectral evidence. All of these compounds displayed inhibition effects to a very susceptible degree in cancer cell line tests. Compound 1 also exhibited significant antioxidant capacity in the free radical 1,1-diphenyl-2-picrylhydrazyl tests. 相似文献
66.
Microchimica Acta - We report on a rapid and effective method for the determination of methylcyclopentadienyl-manganese tricarbonyl (MMT) in water and gasoline samples. It is based on single drop... 相似文献
67.
Parhoodeh P Rahmani M Hashim NM Sukari MA Lian GE 《Molecules (Basel, Switzerland)》2011,16(3):2268-2273
During our phytochemical investigation of Haplophyllum villosum (Rutaceae), a perennial herb from Iran, a new 4,8-diaryl-3,7-dioxobicyclo-(3,3,0)-octane type lignan, eudesmin A (1), together with four known compounds--eudesmin (2), haplamine (3), umbelliferone (4) and scopoletin (5)--were isolated from aerial parts of the plant. The structures of the compounds were elucidated using NMR spectral analysis (1H-NMR, 13C-NMR, HSQC, COSY and HMBC) as well as UV, IR and MS spectra and comparison with previously reported data. 相似文献
68.
A. K. Singh S. Yadav J. Srivastava S. Rahmani R. K. Singh S. Srivastava 《Journal of the Iranian Chemical Society》2011,8(3):622-635
The kinetic and mechanistic studies of homogeneously Rh(III)-catalysed oxidation of D-xylose and L-sorbose by Nbromoacetamide (NBA) in perchloric acid medium were carried out at 40 °C. The reactions were first-order with respect to each of [NBA], [Rh(III)] and [H+] and zero-order in [sugar]. Variation of [Cl?] showed positive effect while variation of [Hg(OAc)2] showed negative effect on the rate of the reactions. Addition of acetamide (NHA) had a negative effect on the rate of the reaction. The rate of the reaction was unaffected by the change in ionic strength (??) of the medium. Various activation parameters were calculated with the help of pseudo-first-order rate constant, k1, obtained at four different temperatures. The mechanisms involving RhCl4(H2O)2 ?, as reactive species of rhodium(III), and H2OBr+, as reactive species of NBA, are proposed which find support from the spectrophotometric evidence and activation parameters, especially the entropy of activation. 相似文献
69.
We compute fractal dimension and permutation entropy for healthy and people who have experienced heart failure. Our result shows that permutation entropy is a suitable approach as well as detrend fluctuation analysis (DFA). The result of DFA shows that the fractal dimensions for healthy and heart failure are different as well as the permutation entropy result. The fluctuation value for permutation entropy for an individual who has experienced heart failure is bigger than for a healthy person. There is some specific change in the interbeat signal of a person who has experienced heart failure, but there is not previous trend for a healthy person. 相似文献
70.
Mohammad Rahmani 《代数通讯》2013,41(11):4361-4372
The purpose of this paper is to calculate all the character tables of Hecke algebras associated with finite Chevalley groups of exceptional type and their maximal parabolic subgroups when they are commutative. In the case when the groups are of classical type, the character values of Hecke algebras are expressed by using the q-Krawtchouk polynomials and the q-Hahn polynomials (See [10] and [15]). On the other hand, the character tables of commutative Hecke algebras associated with exceptional Weyl groups and their maximal parabolic subgroups are given in [12]. In §1, we discuss the structure of Hecke algebras and in §2, we calculate all the character tables of these commutative Hecke algebras associated with finite Chevalley groups of exceptional type. Although some of them are well known, we include them for completeness 相似文献