In view of the disadvantages of concentration polarization and trade-off effects in the application of membrane in desalination field, oxide-nano graphene oxide/polyamide (O-NGO/PA) loose intermediate layer and PA ultra-thin dense layer were introduced to fabricate PA/O-NGO/polyphenylene sulfide composite membrane with sandwich structure via multi-step interfacial polymerization (MS-IP) method. The selective permeation mechanism of ultrathin layer produced by different aqueous monomers (PIP and MPD) was studied, the effect of its physicochemical structure on the relief of concentration polarization phenomenon and the breakthrough of trade-off effect was analyzed. The ultra-thin and dense PA layer mainly played the role of interception and shortened the water molecular penetration path. In the retention test of metal salt solution, compared with the rough surface, it was found that the smooth surface was more conducive to the diffusion of intercepted metal ions into the feed solution, thus alleviating the concentration polarization phenomenon.
Polyaniline nanofibers were prepared by interfacial polymerization with different organic solvents such as chloroform and carbon tetrachloride. Field emission scanning electron microscopy and transmission electron microscopy were used to study the morphological properties of polyaniline nanofibers. Chemical characterization was carried out using Fourier transform infrared spectroscopy, UV-Vis spectroscopy, and X-ray diffraction spectroscopy and surface area was measured using BET isotherm. Polyaniline nanofibers doped with lithium hexafluorophosphate were prepared and their electrochemical properties were evaluated. 相似文献
A comparative study of thermal and thermal-oxidative degradation processes for polyethylene/organically modified montmorillonite
(PE-MMT) nanocomposites, prepared by the ethylene intercalative polymerization in situ with or without subsequent addition
of an antioxidant is reported. The results of TGA and time/temperature-dependent FTIR spectroscopy experiments have provided
evidence for an accelerated formation and decomposition of hydroperoxides during the thermal oxidative degradation tests of
PE-MMT nanocomposites in the range of 170–200 °C as compared to the unfilled PE, thus indicating to a catalytic action of
MMT. It has been shown that effective formation of intermolecular chemical cross-links in the PE-MMT nanocomposite has ensued
above 200 °C as the result of recombination reactions involving the radical products of hydroperoxides decomposition. Apparently,
this process is induced by the oxygen deficiency in PE-MMT nanocomposite due to its lowered oxygen permeability. It is shown
that the intermolecular cross-linking and dehydrogenation reactions followed by the shear carbonization lead to appreciable
increase of thermal-oxidative stability of PE nanocomposite, as compared to that of pristine PE. Notably, the TGA traces for
the antioxidant-stabilized PE-MMT nanocomposites recorded in air were quite similar to those obtainable for the non-stabilized
PE-MMT nanocomposites in argon. The results of treatment of the experimentally acquired TGA data in frames of an advanced
model kinetic analysis are reported and discussed. 相似文献
Here, we describe a new technique for microencapsulating pyriproxyfen, a widely used insect growth regulator. Using interfacial polymerization, we successfully prepared self-bursting microcapsules that retained their shape when suspended in water but break open quickly after the water evaporates. In order to investigate the self-bursting phenomenon, we studied the relationship between formulation factors such as volume median diameter (D) or wall thickness (T) and the physical strength of the obtained polyurethane films. As a result, it was found that T and the structure of isocyanate affected the self-bursting phenomenon. 相似文献
ZnO nanorods are prepared by a hydrothermal process with cetyltrimethylammonium bromide (CTAB) and zinc powder at 182°C. The samples are characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The gas sensing properties of the materials have been investigated. The results indicate that the as-prepared ZnO nanorods are uniform with diameters of 40–80 nm and lengths about 1 μm, the relatively high sensitivity and stability of these sensors made from ZnO nanorods demonstrate the potential for developing a new class of stable and very sensitive sensors. 相似文献
A high strength multi-walled carbon nanotube (MWCNT)/shape memory polyurethane composite (SMPC) was prepared by in situ polymerization. The effect of MWCNT content and its dispersion on the microstructure, mechanical, and shape memory property of the SMPC were studied by scanning electron microscopy, universal testing machine, and dynamic mechanical analysis. The results showed that MWCNTs can be well dispersed in the composites and the composites with homogeneous dispersion of MWCNTs exhibited superior mechanical properties for MWCNTs supplied cross-link netpoints in the composites. And the materials with 97 % of recovery ratios (Rr) and 94 % of fixing ratios (Rf) indicated that this SMPC is a prominent potential candidate for smart actuator. 相似文献
Columnar CeO2 nanostructures are grown on alumina substrates by a template- and catalyst-free Chemical Vapor Deposition (CVD) approach and subsequently tested as resistive gas sensors of CH3COCH3, H2, NO2. The sensor response is stable and reproducible throughout the whole working temperature range (200-500 degrees C) and directly dependent on the analyte gas and the adopted operating conditions. The higher sensitivity with respect to that displayed by continuous CeO2 thin films demonstrates the potential of fabricating nanostructured sensing devices characterized by improved functional performances. 相似文献
Amphiphilic, PEGylated gold nanoparticles, of approximately 2 nm average core diameter, were synthesized by reduction of hydrogen tetrachloroaurate in the presence of the ligand (1-mercaptoundec-11-yl)tetra(ethylene glycol). These PEGylated gold nanoparticles were found to assemble cleanly at the oil-water interface. This self-assembly process gave a microencapsulated oil phase, water as the continuous phase, and a monolayer of gold nanoparticles at the oil-water interface. The capsules could be cross-linked from the organic phase by reaction of the chain-end hydroxyl groups of the PEG ligands with suitable electrophiles such as terephthaloyl chloride. 相似文献