共查询到19条相似文献,搜索用时 187 毫秒
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蒙脱土/阳离子偶氮染料插层纳米复合物离子交换吸附 总被引:4,自引:0,他引:4
从有机阳离子与蒙脱土离子交换吸附原理出发,推导出吸附等温式和表面二维状态方程理论关系,给出了热失重确定吸附量的数据处理方法.选择具有光致变色功能、整个分子共轭的有机阳离子GTL作为插层剂,成功制备了一系列插层纳米复合物.GTL阳离子交换吸附实验数据符合推导出的吸附等温式,插层复合物界面压强π随其含水量增大而线性减小,在较低π下,层间GTL以平行于蒙脱土片层表面的单分子层形态排列;随着π增大,层间GTL以倾斜于蒙脱土片层表面的头尾交指型团聚体形态排列;在更大的π下,层间GTL倾向垂直于蒙脱土片层表面成双分子层排列,其尾端重叠自组装形成超分子共轭纳米结构,层间GTL热稳定性大幅度提高。 相似文献
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具有伸展链构象聚苯胺/蒙脱土混杂纳米复合物的合成与表征 总被引:29,自引:0,他引:29
报道了具有聚苯胺伸展链构象的聚苯胺/ 粘土( P An/ M M T) 混杂纳米复合物的合成与表征.用插层聚合的方法将聚苯胺分子链嵌入层状蒙脱土的片层之中,从而得到一种高电导率的聚苯胺/ 层状硅酸盐混杂纳米复合物.通过 X 射线衍射( X R D) ,付立叶红外( F T I R) ,四探针电导率测量以及定性和定量的电子光谱分析等手段对产物进行了表征,结果表明,90 % 以上的聚苯胺的分子链被插入蒙脱土的片层中间.由于聚苯胺分子链在受限的纳米空间生成,聚苯胺以伸展的单分子链构象存在.该构象在苯胺的通常聚合中不可能生成.通过对聚合过程进行吸收光谱监测,发现该聚合是扩散控制过程. 相似文献
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动态扭振法研究聚甲基丙烯酸甲酸/蒙脱土纳米复合材料的本体插层聚合 总被引:3,自引:0,他引:3
用动态扭振法研究塑性塑料聚甲基丙烯酸甲酸(PMMA)/蒙脱土(MMT)复合体系的本体插层聚合,并试用处理交联体系固化的Folry理论,非平衡态热力学涨落理论和Avrami方程研究PMMA/MMT复合体系的本体插层聚合,求取表观活化能Ea.实验发现,PMMA/MMT插层聚合转化率曲线中后期与热固性树脂的固化曲线极为类似,表明剥离后的蒙脱土片层在复合材料中起到交联点的作用。 相似文献
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研究了利用LB膜技术制备的蒙脱土-钌(II)螯合物杂化膜(Clay-Ru)修饰电极对单磷酸鸟苷的光电催化氧化行为.实验结果表明:(1)蒙脱土-钌(Ⅱ)螯合物的纳米单层杂化膜的平均厚度约为(3.4±0.5)nm;(2)紧密排列于ITO电极表面的非电活性蒙脱土的加入降低了电极的电化学活性,但有效提高了电极的稳定性;(3)具有供电子能力的单磷酸乌苷(GMP)的加入,能大大提高ITO/Ru和ITO/Clay-Ru修饰电极的电子传递效率;(4)纳米单层蒙脱土-钌(Ⅱ)螯合物杂化膜修饰电极的电子传递直接通过蒙脱土纳米单层进行. 相似文献
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插层聚合制备聚丙烯/蒙脱土纳米复合材料及其结构性能表征 总被引:32,自引:0,他引:32
将插层聚合的概念引入烯烃聚合,制备了聚丙烯/蒙脱土(PP/MMT)纳米复合材料。X射线衍射和TEM分析结果表明,蒙脱土在聚丙烯基体中达到了纳米级的分散,动态力学性能研究结果表明,在高于Tg的温度区域内PP/MMT纳米复合材料的储能模量(E′)成倍增加,加入8%的蒙脱土(MMT),PP/MMT的E′提高近3倍。PP/MMT的玻璃化转变温度Tg有一定程度的提高,随蒙脱土含量的增加,PP/MMT的热分解温度和热变形温度(HDT)都有大幅度提高。 相似文献
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甲苯—2,4—二异氰酸酯修饰蒙脱土及聚苯乙烯/蒙脱土纳米复合材料?… 总被引:14,自引:0,他引:14
用FTIR和WAXD法研究了甲苯-2,4-二异氰酸酯(TDI)的邻位和对位异氰酸酯基因与蒙脱土表面羟基的修饰反应,在此基础上提出了结构模型;用TDI修饰后的蒙脱土成功制备了插层型聚苯乙烯/蒙脱土纳米复合材料,并用WAXD和TEM进行了表征。实验结果表明,修饰后TDI与蒙脱土表面形成化学键,使蒙脱土的片层间距显著增大,十六烷基三甲基溴化铵(CTAB)在蒙脱土层间由双层平行排列转变为双层脂肪链倾斜方式 相似文献
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Monoolein (MO) cubic phase, whose MO/azobenzene mass ratios were 1:0, 1:0.0025, 1:0.005, and 1:0.025, was prepared by a melt-hydration method. According to the polarized optical micrographs and the differential thermograms, the phase transition temperature of the cubic phase was lower as the content of azobenzene was higher, and it decreased upon the subsequent irradiation of UV light for 1 hour and visible light for 1 hour. The photoirradiation significantly promoted the release of methylene blue (a water-soluble dye) loaded in the cubic phase only when the MO/azobenzene mass ratio was 1:0.025. The photoirradiation could promote the release of Nile red (an oil-soluble dye) even when the MO/azobenzene mass ratio was less than 1:0.025. The higher photo-susceptibility of Nile red release was possibly because the dye would be intercalated in the MO lipid matrix and the photoirradiation could affect the lipid matrix property. 相似文献
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《Arabian Journal of Chemistry》2020,13(2):3974-3987
Carboxymethylcellulose (CMC) acts as a coating material for a magnesium-layered hydroxide-3-(4-methoxyphenyl)propionate (MLH-MPP) nanocomposite via spontaneous self-assembly. The resulting product is called a magnesium-layered hydroxide-3-(4-methoxyphenyl)propionate/carboxymethylcellulose (MLH-MPP/CMC) nanocomposite. The XRD pattern of the MLH-MPP/CMC nanocomposite showed that MPP was maintained in the interlayers of the MLH, thus confirming that CMC is only deposited on the surface of the MLH-MPP nanocomposite. These findings were also supported by FTIR spectra, SEM and TEM. TGA data showed that the thermal stability of the intercalated MPP was significantly enhanced compared to pure MPP and uncoated nanocomposite. The release of MPP from the interlayers of MLH-MPP/CMC nanocomposite showed slower release than did uncoated nanocomposite and followed pseudo–second-order kinetics. Since the herbicide, MPP was released from the synthesised nanocomposite in a sustained manner, thus, it has excellent potential to be used as a controlled-release herbicide formulation. 相似文献
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Rafael Marangoni José Eduardo Ferreira da Costa Gardolinski Alexandre Mikowski Fernando Wypych 《Journal of Solid State Electrochemistry》2011,15(2):303-311
Zn2Al-layered double hydroxides (LDH) were intercalated with anions of the dyes Orange G, Orange II, and Methyl Orange by alkaline
co-precipitation of aqueous solutions of zinc chloride and aluminum nitrate simultaneously in the presence of dye sodium salts.
Transparent, homogeneous, and colored nanocomposite films were obtained by casting after dispersing the dye-intercalated LDHs
(pigments) into commercial poly(vinyl alcohol) (PVA). The films were characterized by X-ray diffraction, ultraviolet–visible
spectroscopy, thermal analysis (thermogravimetric analysis (TGA)) and differential thermal analysis (DTA)), and mechanical
testing. Mechanical reinforcement of the PVA compounded with the dye-intercalated LDHs was achieved, and reasonable increases
in Young’s modulus and ultimate tensile strength were observed with as little as 0.5% added filler, while larger amounts tended
to decrease the reinforcement effect. These results demonstrate the onset of a new range of potential applications for layered
double hydroxide intercalated with dyes in the preparation of polymer composite multifunctional materials. 相似文献
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N. A. Davidenko I. I. Davidenko I. A. Savchenko A. N. Popenaka N. A. Derevyanko A. A. Ishchenko A. V. Kulinich 《High Energy Chemistry》2008,42(2):123-126
Absorption spectra of poly[4-metacryloyloxy-(4′-carboxy-3′-oxy)azobenzene] films and their complexes with cobalt, without additives or doped with a merocyanine dye whose absorption spectrum lay in the near IR region, were studied before and after switching on an external electric field. An external electric field effect was found on the light transmittance of films within the dye absorption region, which indicated sensitization of the electrooptical effect. The electrooptical properties of the films resulted from spatial reorientation of dipole moments of azobenzene groups in an external electric field, which initiated turning of dye molecules. A phenomenological model was proposed to explain the sensitization of the electrooptical effect. 相似文献
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Characterization of rhodamine 6G aggregates intercalated in solid thin films of laponite clay. 2 Fluorescence spectroscopy 总被引:2,自引:0,他引:2
Martínez Martínez V López Arbeloa F Bañuelos Prieto J López Arbeloa I 《The journal of physical chemistry. B》2005,109(15):7443-7450
The photoluminescence response of Rhodamine 6G (R6G) laser dye intercalated into solid thin films of Laponite (Lap) clay is studied as a function of dye loading. Fluorescence spectroscopy (steady-state and time-resolved techniques) was used to characterize the R6G species adsorbed into the solid films. For very diluted R6G loadings (=0.1% CEC, i.e., the percentage of the total cation exchange capacity of Lap) the fluorescence properties of R6G monomer were characterized, which presents an emission band centered at 548 nm, an average lifetime of 4.2 ns, and a fluorescence efficiency higher than that of the R6G monomer in liquid solution. By increasing the loading, dye molecules tend to self-aggregate, and different dimers are formed in moderate dye concentrations (in the 1-25% CEC range): oblique head-to tail J-type dimers, with weak emission bands at around 575 nm; and sandwich H-type dimers, as efficient quenchers of the fluorescent emission. Higher-order aggregates of R6G in Lap films are formed in high loading samples (>40% CEC), with a reminiscent fluorescence band at around 600 nm. 相似文献
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Summary: In this study, chitosan nanocomposite films were prepared using a solvent-casting method by incorporation of an organically modified montmorillonite (Cloisite 10A). The effect of filler concentration on the water vapor permeability, oxygen permeability, mechanical and thermal properties of the composite films was evaluated. The structure of nanocomposites and the state of intercalation of the clay were characterized by XRD. The water vapor permeability of pure chitosan films was measured as a function of relative humidity (RH). It was found that the permeability value increased with an increase in RH. The water vapor and gas permeability values of the composite films decreased significantly with increasing filler concentration. Permeation data was fitted to various phenomenological models predicting the permeability of polymer systems filled with nanoclays as a function of clay concentration and aspect ratio of nanoplatelets. According to the XRD results, an increase in basal spacing was obtained with respect to pure clay for chitosan/clay nanocomposites. This demonstrated the formation of intercalated structure of clay in the polymer matrix. Tensile strength and elongation at break of the composites increased significantly with the addition of clay, however the thermal and color properties of the films were not much affected by the intercalation of clay into polymer matrix. 相似文献
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The crystallization of uniaxial hot drawn syndiotactic polystyrene/multi-walled carbon nanotube (sPS/MWCNT) nanocomposite films was studied by FTIR spectroscopy. The effects of MWCNT content, draw ratio and drawing temperature on the sPS crystallinity were investigated. The sPS/MWCMT nanocomposite films show reduced crystallinities with the increase of MWCNT content. In addition, with the increase of draw ratio, both the pure sPS and the sPS/MWCNT nanocomposite drawn films exhibit increased crystallinity. The effect of drawing temperature on the sPS crystallization is complex. In a temperature range of 100―135 ℃, the crystallinity decreases with drawing temperature, whereas it increases at 140 ℃ for both pure sPS and its nanocomposite films. 相似文献
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The simple LBL technique was introduced to fabricate green nacre-like chatosan/montmorillonite(CHI/MMT) films. The results of SEM and XRD analysis demonstrate that the produced CHI/MMT composites films stacked densely together to bring out well-defined nacre-like brick-mortar structure. The nanoindentation technique is used to characterize the mechanical properties of the layered nanocomposite films, which show enhanced mechanical modulus(up to ~6.64 GPa) compared with the pure chitosan. 相似文献
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Klika Z Capková P Horáková P Valásková M Malý P Machán R Pospísil M 《Journal of colloid and interface science》2007,311(1):14-23
The distribution of various aggregates (dimers, trimers, and tetramers) of methylene blue (MB) formed in aqueous solution at various concentrations of dye has been calculated using the equilibrium aggregation constants betaq. Two montmorillonite samples with different cation exchange capacities, surface areas, and interlayer distances d001, Na-SWy, and Ca-Cheto, were saturated with methylene blue (MB) solutions with various ratios between monomers and higher aggregates of dye. The total amount of MB in the intercalated montmorillonite samples (MB-SWy and MB-Cheto) increases with increasing concentration of dye in water solutions, i.e., with increasing aggregates/monomers ratio of MB in water solution. In all intercalated montmorillonite samples with methylene blue except guest qth aggregate cations [MBqq+] low contents of Na+ (in MB-SWy) and Ca2+ (in MB-Cheto) cations were also determined. A very good positive correlation between the basal spacing d001 and the MB/montmorillonite molar ratio was revealed for saturated MB-montmorillonite samples. Structural analysis using a combination of diffraction data with molecular modeling revealed the differences in the interlayer arrangement of MB guests in MB-SWy and MB-Cheto intercalates. Also, fluorescence measurements showed the strong effect of the silicate layer charge on the spectroscopic behavior of MB guests intercalated in montmorillonite. Methylene blue exhibits a certain luminescence in MB-SWy samples with cation exchange capacity 0.80 meq g-1 and almost no luminescence in MB-Cheto samples with higher cation exchange capacity 1.50 meq g-1. 相似文献