• Bulletin of the Korean Chemical Society
• /
• 제34권5호
• /
• pp.1391-1396
• /
• 2013

The photocontrolled reduction of silver nitrate to silver (Ag) nanoparticles on honeycomb-patterned poly(N-vinylcarbazole) (PVK)-cellulose triacetate (CTA) composite thin films was studied. The composites were prepared via the oxidative polymerization of N-vinylcarbazole with ferric chloride using different CTA concentrations. A honeycomb-patterned film was fabricated by casting the composite solution under humid conditions. Ag particles with a homogeneous distribution were produced by the composite film in a moderate CTA concentration, whereas aggregated Ag was obtained from the pure PVK film.

• Membrane and Water Treatment
• /
• 제8권6호
• /
• pp.563-574
• /
• 2017

Antibacterial effective, high performanced, novel ZnO embedded composite membranes were obtained by blendig ZnO nanoparticles with polysulfone. IR, TG/DTG, XRD and SEM analysis were performed to characterize structure and morphology of ZnO nanoparticles and composite membranes. Contact angle, EWC, porosity and pore structure properties of composite membranes were investigated. Cross-flow filtration studies were performed to investigation of performances of prepared membranes. It was found from the cross section SEM images that ZnO nanoparticles dispersed homogenously up to additive amount of 2% and the membrane skin layer thicknesses increased in the presence of ZnO. Contact angle of pure PSf membranes were reduced from $70^{\circ}$ to $55^{\circ}$ after addition of 4% ZnO. Porosity of composite membrane contains 1% ZnO was higher about 22% than pure PSf membrane. BSA rejection ratio and PWF of 0.5% ZnO embedded composite membrane became 2.2 and 2.3 times higher than pure PSf membrane. It was determined from flux recovery ratios that ZnO additive increased the fouling resistance of composite membranes. Also, the bacterial killing ability of ZnO is well known and there are many researches related to this in the literature. Therefore, it is expected that prepared composite membranes will show antibacterial effect.

• Earthquakes and Structures
• /
• 제15권3호
• /
• pp.285-294
• /
• 2018

In this study, nonlinear dynamic response of a concrete plate retrofit with Aluminium oxide ($Al_2O_3$) under seismic load and magnetic field is investigated. The plate is a composite reinforced by Aluminium oxide with characteristics of the equivalent composite being determined using Mori-Tanka model considering agglomeration effect. The plate is simulated with higher order shear deformation plate model. Employing nonlinear strains-displacements, stress-strain, the energy equations of column was obtained and using Hamilton's principal, the governing equations were derived. Differential quadrature method (DQM) in conjunction with Newark method is applied for obtaining the dynamic response of structure. The influences of magnetic field, volume percent of nanoparticles, geometrical parameters of column, agglomeration and boundary conditions on the dynamic response were investigated. Results showed that with increasing volume percent of nanoparticles, the dynamic deflection decreases.

• 한국복합재료학회:학술대회논문집
• /
• 한국복합재료학회 2005년도 추계학술발표대회 논문집
• /
• pp.87-90
• /
• 2005

This paper presents an evaluation of the effect of titanium dioxide nanoparticles in sulfonated poly(ether ether ketone) (SPEEK) with sulfonation degree of 57%. A series of inorganic-organic hybrid membranes were prepared with a systematic variation of titanium dioxide nanoparticles content. Their water uptake, methanol permeability and proton conductivity as a function of temperature were investigated. The results obtained show that the inorganic oxide network decreases the proton conductivity and water swelling. It is also found that increase in inorganic oxide content leads to decrease of methanol permeability. In terms of morphology, membranes are homogeneous and exhibit a good adhesion between inorganic domains and the polymer matrix. The properties of the composite membranes are compared with standard nafion membrane.

• Bulletin of the Korean Chemical Society
• /
• 제33권7호
• /
• pp.2309-2314
• /
• 2012

Ag deposited N-$TiO_2$ composite nanoparticles were prepared via $NH_3$ plasma treatment. X-ray diffraction, UV-vis spectroscopy, photoluminescence, and X-ray photoelectron spectroscopy were used to characterize the prepared $TiO_2$ samples. The plasma treatment did not change the phase composition and particle sizes of $TiO_2$ samples, but extended its absorption edges to the visible light region. The photocatalytic activities were tested in the degradation of an aqueous solution of a reactive dyestuff, methylene blue, under visible light. The photocatalytic activities of Ag deposited N-$TiO_2$ composite nanoparticles were much higher than Ag-$TiO_2$, N-$TiO_2$, and P25. A possible mechanism for the photocatalysis was proposed.

• Macromolecular Research
• /
• 제16권2호
• /
• pp.163-168
• /
• 2008

Polystyrene/gold nanoparticle (PS/AuNP) composite fibers were fabricated using an electrospinning technique. Transmission electron microscopy (TEM) showed that the diameters of the naphthalenethiol-capped gold nanoparticles (prior to incorporation into the PS fibers) ranged from 2 to 5 nm. UV-vis spectroscopy revealed the surface plasmon peaks of the gold nanoparticles centered at approximately 512 nm, indicating that nano-sized Au particles are well-dispersed in solution. This was consistent with the TEM observations. The electrospun nanofibers of PS/AuNP composites were approximately 60-3,000 nm in diameter. The surface morphology of the PS/AuNP composite and the dispersability of the Au nanoparticles inside of PS after electrospinning process were investigated by SEM and TEM. The thermal behavior of the pure PS and PS/AuNP nanocomposites and fibers were examined by DSC.

• 폴리머
• /
• 제36권6호
• /
• pp.721-726
• /
• 2012

해수에서 사용되는 음향 소나 시스템의 호스 소재로 열가소성 폴리우레탄 탄성체가 사용되고 있다. 장기간 소나 운용을 위해서는 향상된 기계적 물성과 해수 및 오일에 의한 낮은 팽윤도를 갖는 소재가 요구된다. 해수 적용에 적합한 향상된 물성의 복합재료를 개발하기 위해 실리카 나노입자 표면에 폴리우레탄을 그래프트시킨 TPU-g-silica 나노입자를 제조하고 이를 폴리우레탄과 혼련하여 복합재료를 제조하였다. 실리카 나노입자를 포함한 폴리우레탄 복합재료는 실리카 입자의 표면 처리에 상관없이 폴리우레탄보다 향상된 인장강도와 낮은 팽윤도를 나타내었다. 폴리우레탄 복합재료들이 같은 함량의 실리카 입자를 포함한 경우, TPU-g-silica를 포함한 복합재료가 표면처리를 하지 않은 실리카 입자를 포함한 복합재료에 비해 보다 향상된 인장강도와 낮은 팽윤도를 나타내었다. 장시간 오일에 함침 후 인장강도를 측정한 결과 폴리우레탄에 비해 TPU-g-silica를 포함한 복합재료가 높은 인장강도를 유지하였다.

• Carbon letters
• /
• 제14권4호
• /
• pp.206-209
• /
• 2013

Nanocomposites comprised of graphene oxide (GO) nanosheets and magnesium oxide (MgO) nanoparticles were synthesized by a sol-gel process. The synthesized samples were studied by X-ray powder diffraction, atomic force microscopy, transmission electron microscopy, and energy-dispersive X-ray analysis. The results show that the MgO nanoparticles, with an average diameter of 70 nm, are decorated uniformly on the surface of the GOs. By controlling the concentration of the MgO precursors and reaction cycles, it was possible to control the loading density and the size of the resulting MgO particles. Because the MgO particles are robustly anchored on the GO structure, the MgO/GOs nanocomposites will have future applications in the fields of adsorption and chemical sensing.

• Bulletin of the Korean Chemical Society
• /
• 제33권5호
• /
• pp.1613-1616
• /
• 2012

Ni nanoparticles-$TiO_2$ nanotube arrays (Ni/$TiO_2NTs$) composites were prepared by pulsed electrodeposition method and subsequently characterized by means of field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD) and energy dispersive X-ray spectroscopy (EDX). The FESEM results showed that highly dispersed Ni nanoparticles were not only loaded on the top of the $TiO_2NTs$ but also within the tubular structure, and the particle size of Ni prepared at different current amplitude (100, 200 and 300 $mA{\cdot}cm^{-2}$) was in the range of 15 to 70 nm. The electrochemical studies indicated that Ni nanoparticles loaded on the highly ordered $TiO_2NTs$ are readily accessible for electrochemical reactions, which improve the efficiency of the Ni nanoparticles and $TiO_2NTs$. A maximum specific capacitance (27.3 $mF.cm^{-2}$) was obtained on the Ni/$TiO_2NTs$ composite electrode that prepared at a current of 200 $mA.cm^{-2}$, and the electrode also exhibited excellent electrochemical stability.

• Carbon letters
• /
• 제25권
• /
• pp.1-13
• /
• 2018

Gold functionalized graphene oxide (GOAu) nanoparticles were reinforced in acrylonitrile-butadiene rubbers (NBR) via solution and melt mixing methods. The synthesized NBR-GOAu nanocomposites have shown significant improvements in their rate of curing, mechanical strength, thermal stability and electrical properties. The homogeneous dispersion of GOAu nanoparticles in NBR has been considered responsible for the enhanced thermal conductivity, thermal stability, and mechanical properties of NBR nanocomposites. In addition, the NBR-GOAu nanocomposites were able to show a decreasing trend in their dielectric constant (${\varepsilon}^{\prime}$) and electrical resistance on straining within a range of 10-70%. The decreasing trend in ${\varepsilon}^{\prime}$ is attributed to the decrease in electrode and interfacial polarization on straining the nanocomposites. The decreasing trend in electrical resistance in the nanocomposites is likely due to the attachment of Au nanoparticles to the surface of GO sheets which act as electrical interconnects. The Au nanoparticles have been proposed to function as ball rollers in-between GO nanosheets to improve their sliding on each other and to improve contacts with neighboring GO nanosheets, especially on straining the nanocomposites. The NBR-GOAu nanocomposites have exhibited piezoelectric gauge factor (${GF_{\varepsilon}}^{\prime}$) of ~0.5, and piezo-resistive gauge factor ($GF_R$) of ~0.9 which clearly indicated that GOAu reinforced NBR nanocomposites are potentially useful in fabrication of structural, high temperature responsive, and stretchable strain-sensitive sensors.