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Anionic copolymerizations of styrene (M1) with excess 1-(4-dimethyl-aminophenyl)-1-phenylethylene (M2) were conducted in benzene at 25°C for 24h, using sec-butyllithium as initiator. Narrow molecular weight distribution copolymers with M?;n = 16.1 × 103 g/mol (M?w/M?n = 1.04) and 38.2 × 103g/mol (M?w/M?n = 1.05), and 24 and 38 moles of M2 per macromolecule, respectively, were characterized by size exclusion chromatography, 1H NMR spectroscopy and DSC. The monomer reactivity ratio, r1 = 5.6, was obtained from the copolymer composition at complete consumption of M1, assuming that the rate constant k22 =0,i.e. r2 =0. The polymers exhibited Tg values of 128 and 119°C, respectively, which correspond to an estimated Tg = 217°C for the hypothetical homopolymer of M2. 相似文献
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采用苯乙烯膦酸与脂肪醇组成的复合捕收剂浮选金红石矿取得了较好效果,通过改进的Hallimond管浮选试验、吸附量测定试验、捕收剂溶液表面张力和金红石表面接触角的测量以及X射线光电子能谱测试(XPS),详细研究了复合捕收剂的协同作用机理。试验结果表明:苯乙烯膦酸在金红石表面发生了化学吸附,脂肪醇与苯乙烯膦酸相互联结,其疏水基指向水相,从而增强了金红石表面的疏水性,提高浮选结果。 相似文献
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以亚磷酸三乙酯与氯化苄或对甲基氯化苄反应制备W ittig试剂,再与N,N-二(甲)苯基氨基苯甲醛反应,高收率制备了N,N-二(4-甲基苯基)-4-〔2-(4-甲基苯基)乙烯基〕苯胺(Ⅱa)、N,N-二(4-甲基苯基)-4-(2-苯基乙烯基)苯胺(Ⅱb)、N,N-二苯基-4-〔2-(4-甲基苯基)乙烯基〕苯胺(Ⅱc)、N,N-二苯基-4-(2-苯基乙烯基)苯胺(Ⅱd)4种空穴传输材料,收率分别达96.4%、92.1%、89.4%、92.6%。产物通过元素分析、红外光谱和质谱等进行了表征。以Y-TiOPc为电荷产生材料,合成化合物为空穴传输材料,制备了有机光导体,并进行了光电性能测试,化合物Ⅱa、Ⅱb和Ⅱc光敏性均在0.04~0.05 lx.s,是性能优异的电荷传输材料。 相似文献
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Jagadeeswari Sivanadanam Ramesh Mukkamala Sudip Mandal Raman Vedarajan Noriyoshi Matsumi Indrapal Singh Aidhen Kothandaraman Ramanujam 《International Journal of Hydrogen Energy》2018,43(9):4691-4705
Six triphenylamine-based dyes were explored for their application in dye-sensitized solar cells (DSSCs). Dyes 1–3 and dyes 4–6 possess cyanoacrylic acid (C-acceptor) and rhodanine-3-acetic acid (R-acceptor), respectively. Stilbene (in dyes 2 and 5) and bis(styryl)benzene (in dyes 3 and 6) were used as π-spacers. There is no π-spacer in the dye 1 and 4. To elucidate the role of π-spacers, optical, electrochemical, and photovoltaic properties of the dyes were studied. Among C-acceptor dyes, dye 2 exhibits the highest light-to-electricity conversion efficiency of 4.45%, followed by dye 3 (4.16%). Similarly, among R-acceptor dyes, dye 5 is the best. These results indicate that stilbene is a better π-spacer over bis(styryl)benzene. Although bis(styryl)benzene could extend the light absorption range (in dye-adsorbed TiO2 film), its tendency to promote intermolecular π-π stacking is possibly the reason for its poor performance in DSSCs. Furthermore, the conjugation break in the R-acceptor moiety attached to the TiO2 surface limits the electron injection of R-acceptor dyes poorer than C-acceptor dyes. Density functional theory calculations were performed for the dye-(TiO2)8 cluster, assuming a bidentate chelation of a carboxylic acid group with Ti4+ of TiO2 anatase. The natural bond orbital (NBO) analysis indicated relatively more electron-accepting ability of cyanoacrylic acid over rhodanine-3-acetic acid. 相似文献
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Kenji Kinashi Hironori ShinkaiWataru Sakai Naoto Tsutsumi 《Organic Electronics》2013,14(11):2987-2993
Photorefractive (PR) performances of methyl-substituted poly(triarylamine) (PTAA)-based PR device were demonstrated using chemically modified electrodes (CMEs) of self-assembled monolayer (SAM) coated indium-tin-oxide (ITO) electrodes. The SAM-ITO electrodes successfully suppressed dark current which blocks the formation of space-charge field and also causes the dielectric breakdown. The PR device consisted of composite of PTAA, 4-azacycloheptylbenzylidenemalononitrile (7-DCST), N-ethylcarbazole (ECz), and [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) sandwiched between the SAM-ITO electrodes. The PR devices showed the PR performances: optical gain Γ, refractive index Δn, diffraction efficiency η, response time τ, sensitivity S, phase shift Φ, trap-limited field Eq, number density of traps NT, and space-charge field ESC. The remarkable response time of 11.3 ms was achieved at the low electric field of 20 V μm−1, which was comparable to the response time of high-definition television (HDTV) quality of 16 ms. Our approach will widen the usage of higher mobility materials to photorefractive field and give us more favorable materials to achieve the best performance of photorefractivity in the future. 相似文献
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为研发新型Aβ正电子显像剂,设计合成对甲苯磺酰氧基取代的苯乙烯基嘧啶化合物Boc-SPm2-OTs和Boc-SPm5-OTs,并通过亲核取代反应进行18F标记,得到18F-SPm2和18F-SPm5,放化纯度均大于99%。18F-SPm2和18F-SPm5均具有适宜的亲脂性(LogP=1~2.5),在生理盐水中可稳定存在3 h以上,能选择性结合Aβ,但其亲和性较弱(Ki分别为246.6 nmol/L和318.2 nmol/L),体内生物分布实验表明,两者初始脑放射性摄取均相对较高,但正常脑组织清除较慢,而且存在明显脱氟现象。初步的研究结果表明,18F-SPm2和18F-SPm5不是理想的Aβ显像剂,需要进行进一步的结构修饰以克服其缺点。 相似文献
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The novel syntheses of 4-(4,5-dihydro-4,4-dimethyl-2-oxazolyl)benzophenone, 1-[4-(4,5-dihydro-4,4-dimethyl-2-oxazolyl)phenyl]-1-phenylethanol and 4,5-dihydro-4,4-dimethyl-2-[4-(1-phenylethenyl)phenyl]oxazole ( 1 ) are described. ω-Oxazolyl polystyrene ( 2 ) was synthesized in quantitative yields by the reaction of poly(styryl)lithium with stoichiometric amounts of 4,5-dihydro-4,4-dimethyl-2-[4-(1-phenylethenyl)phenyl]oxazole ( 1 ) in toluene/tetrahydrofuran (4 : 1 v/v) at −78°C. Deblocking of the oxazoline protecting group by acid hydrolysis followed by saponification quantitatively provides the corresponding aromatic carboxyl chain-end functionalized polystyrene ( 3 ). The functionalization agent and functionalized polymers were characterized by HPLC, thin layer chromatography, size exclusion chromatography, vapor phase osmometry, spectroscopy (1H NMR, 13C NMR and FTIR), potentiometry and elemental analysis. 相似文献
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