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51.
Felix D. Sokolov Damir A. Safin Maria G. Babashkina Nail G. Zabirov Vasiliy V. Brusko Nikolay A. Mironov Dmitry B. Krivolapov Igor A. Litvinov Rafael A. Cherkasov Boris N. Solomonov 《Polyhedron》2007
For N-(thio)phosphorylthioureas of the common formula RC(S)NHP(X)(OiPr)2HLI (R = N-(4′-aminobenzo-15-crown-5), X = S), HLII (R = N-(4′-aminobenzo-15-crown-5), X = O), HLIII (R = PhNH, X = S), HLIV (R = PhNH, X = O), and (N,N′-bis-[C(S)NHP(S)(OiPr)2]2-1,10-diaza-18-crown-6) H2LV, salts LiLI,III,IV, NaLI–IV, KLI–IVM2LV (M = Li+, Na+, K+), Ba(LI,III,IV)2, and BaLV have been synthesized and investigated. Compounds NaLI,II quantitatively drop out as a deposit in ethanol medium, allowing the separation of Na+ and K+ cations. This effect is not displayed for the other compounds. The crystal structures of HLIII and the solvate of the composition [K(Me2CO)LIII] have been investigated by X-ray crystallography. 相似文献
52.
Takuo Sugioka Allan S. Hay 《Journal of polymer science. Part A, Polymer chemistry》2001,39(7):1040-1050
A series of bis(4‐thio‐1,8‐naphthalic anhydride)s and the corresponding bis(N‐amino naphthalimide) derivatives were synthesized from readily available compounds in high yield. A series of novel poly(thioether‐naphthalimide)s, which utilized hydrazine as the diamine, were synthesized by a one‐step polymerization reaction in m‐cresol. Poly(thioether‐naphthalimide)s with inherent viscosities of 0.57–1.73 dL/g were obtained. The polymers were soluble in CHCl3 and were determined to have high molecular weights by means of gel permeation chromatographic analysis. They were soluble in m‐cresol and could be cast into tough films from m‐cresol solution. The glass‐transition temperature (Tg) values of the polyimides ranged from 320 to 353 °C. Polyimides from the bisphenol dianhydride, derived from 9,9‐bis(4‐hydroxyphenyl)fluorene, did not show a clear transition in the DSC analysis. Degradation temperatures for 5% weight loss all occurred above 430 °C in nitrogen. The series of monomers were successfully copolymerized with each other. Monomers 6a and 7a , containing the bisphenol A moiety, could also be copolymerized with perylenetetracarboxylic dianhydride. These copolymers had high Tg's and were thermally stable. The UV–vis absorption properties of the polymers were also examined. © 2001 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 39: 1040–1050, 2001 相似文献
53.
Hans R. Kricheldorf Nicolas Probst Gert Schwarz Günter Schulz Ralph‐Peter Krüger 《Journal of polymer science. Part A, Polymer chemistry》2000,38(19):3656-3664
We prepared 2,2‐dibutyl‐2‐stanna‐1,3‐dithiacycloalkanes from dibutyltin oxide and α,ω‐dimercaptoalkanes. Heterocycles with five‐, six‐, seven‐, or nine‐ring members were used as bifunctional monomers for polycondensations with aliphatic dicarboxylic acid chlorides. These polycondensations conducted in bulk were highly exothermic and yielded poly(thio ester)s with number average molecular weights (Mn's) in the range of 5000–30,000 Da. These poly(thio ester)s proved to be rapidly crystallizing materials with melting temperatures in the range of 90–150 °C. In addition to the success of the new synthetic approach, two interesting and unpredictable results were obtained. All volatile species detectable by matrix assisted laser desorption induced‐time of flight (MALDI‐TOF) mass spectrometry were cyclic oligo‐ and poly(thio ester)s. Second, several polyesters showed a reversible first‐order change of the crystal modification as identified by differential scanning calorimetry measurements and X‐ray scattering with variation of the temperature. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 3656–3664, 2000 相似文献
54.
Matthew C. Davis Andrew J. Guenthner Thomas J. Groshens Josiah T. Reams Joseph M. Mabry 《Journal of polymer science. Part A, Polymer chemistry》2012,50(19):4127-4136
Novel biorenewable bisphenols are obtained through simple and rapid chemical transformation of the natural product trans‐anethole. The corresponding dicyanate esters are thermally cured to give polycyanurate networks. The thermal properties from differential scanning calorimetry, thermogravimetric, and dynamic thermomechanical analyses of the new dicyanate esters compare favorably with similar commercial products. © 2012 Wiley Periodicals, Inc.? J Polym Sci Part A: Polym Chem, 2012 相似文献
55.
十六烷基三甲基溴化铵对脱水四环素和异四环素荧光增强作用研究 总被引:3,自引:0,他引:3
在不同pH值的标准缓冲溶液及不同表面活性剂十六烷基三甲基溴化铵(CTMAB)浓度的胶束溶液环境中,研究了CTMAB对盐酸四环素的降解产物脱水四环素和异四环素的荧光强度的影响。结果表明,CTMAB对脱水四环素和异四环素具有荧光增强作用,荧光增强幅度与介质的pH值和CTMAB浓度有关,在中性和碱性条件下对脱水四环素荧光增强作用较大,在pH=9.2的条件下可使异四环素的荧光强度达到最大值,CTMAB对脱水四环素和异四环素的这种荧光增强作用,为建立较灵敏的盐酸四环素及其降解产物的荧光定量方法提供了依据。 相似文献
56.
Matthew Laskoski Dawn D. Dominguez Teddy M. Keller 《Journal of polymer science. Part A, Polymer chemistry》2006,44(15):4559-4565
New multiple aromatic ether containing oligomeric cyanate ester resins have been synthesized using a modified Ullmann reaction. The oligomeric monomers were prepared by reacting resorcinol and 1,3‐ or 1,4‐dibromobenzene in the presence of potassium carbonate and a catalytic amount of a copper(I) complex in a N,N‐dimethylformamide/toluene mixture. The hydroxyl terminated intermediates were end‐capped with the cyanate moiety by reaction with cyanogen bromide in the presence of triethylamine in dry acetone. The oligomeric cyanate ester monomers are liquid at room temperature, which enhance their processability to polymeric networks. The thermo‐oxidative properties were determined for the new cyanate ester polymers as well as their storage modulus. The length of the aromatic ether spacer between the terminal cyanate ester groups was varied to investigate the effect of changing the spacer length on the properties of the material. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 4559–4565, 2006 相似文献
57.
Ching Hsuan Lin Kai Zhi Yang Tsu Shang Leu Chun Hung Lin Jhao Wei Sie 《Journal of polymer science. Part A, Polymer chemistry》2006,44(11):3487-3502
We synthesized a novel epoxy (dopotep) and cyanate ester (dopotcy) based on a phosphorus‐containing triphenol (dopotriol). The proposed structures were confirmed by IR, mass spectra, NMR spectra, and epoxy‐equivalent‐weight titration. The synthesized dopotep or dopotcy was copolymerized with diglycidyl ether of bisphenol A (DGEBA), 6′,6‐bis(3‐phenyl‐3,4‐dihydro‐2H‐1,3‐benzoxazineyl)methane (F‐a), or dicyanate ester of bisphenol A (BADCY). Thus, copolymers based on DGEBA/dopotep/diphenylmethane (ddm), F‐a/dopotep, BADCY/dopotcy, and DGEBA/dopotcy were developed. The thermal properties, dielectric properties, and flame retardancy of these copolymers were investigated. The curing kinetics of dopotep/ddm and dopotep/diamino diphenylsulfone were studied with differential scanning calorimetry. The microstructure of DGEBA/dopotcy was studied with IR. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 3487–3502, 2006 相似文献
58.
Eva M. Maya Arthur W. Snow Leonard J. Buckley 《Journal of polymer science. Part A, Polymer chemistry》2003,41(1):60-67
A synthesis procedure for and characterization of a tetra‐ortho‐methyl substituted three‐ringed cyanate ester monomer, 4,4′‐[1,3‐phenylenebis(1‐methylethylidene)]bis[2,6‐dimethyl]phenylcyanato, and the corresponding cured resin are described with comparative characterization of the resin analogue without the ortho‐methyl substitutents. The othro‐methylation lowered the dielectric from 2.64 to 2.59 at 1 GHz and from 2.64 to 2.48 GHz at 15 GHz, whereas the tan δ was not significantly affected. Other physical properties also affected included a 40 °C decrease in the glass‐transition temperature, an increase in the thermal‐expansion coefficients, and a reduction in thermogravimetric stability. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 60–67, 2003 相似文献
59.
A new series of bimetallic Lewis acid, Cu(NCO)2(NCS)2Hg, and its complexes, L2Cu(NCO)2(NCS)2Hg (L =thf,dmso, pyridine, nicotinamide and Ph3P are prepared and studied by physical and spectroscopic methods. 相似文献
60.