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1.
The surface of nano-SiO2 was modified by being encapsulated with hydroxy-propyl-methyl cellulose (HPMC), and then co-grafted with acrylates. The grafting conditions, such as pH of the medium, and initiator concentration have been studied. The modified nano-SiO2 particles were characterized by TEM, DSC and FT-IR spectra. TEM images show that the surface of the nano-particles has been successfully modified by a thick layer of film-like polymer in this way. The DSC results show that the decomposition temperature of modified nano-particles of SIO2 is 90 ℃ higher than that of grafted-on polymer. According to the FT-IR spectra, It is convinced that poly-methyl methacrylate ( PMMA ) and poly-acrylic butyl-ester ( PBA ) were co-grafted onto the surface of nano-SiO2. 相似文献
2.
CUI Yali ZHANG Lianying SU Jing ZHANG Caifeng LI Qi CUI Ting JIN Boquan & CHEN Chao . Biochip Research Development Center Northwest University 《中国科学B辑(英文版)》2006,49(6):534-540
Micrometer-sized Fe3O4 particles and nano-sized gold particles were first synthesized by methods of self-aggregation of surface-chemically modified Fe3O4 nanoparticles and citrate reduction of the Au3 to Au0, respectively. Interaction between these two types of particles resulted in the assembly of nano-sized gold particles on the surface of the micrometer-sized Fe3O4 particles, forming an assembled structure with the Fe3O4 core particles around which are attached nano-sized gold parti- cles. The Fe3O4/Au structure is named GoldMag particles with assembled structure. The synthetic process, structure, and magnetic property of the GoldMag particles were analyzed. GoldMag particles with assembled structure have an irregular shape, rough surface with a diameter of 2―3 μm. These particles exhibit the superparamagnetic property with saturated magnetization of 41 A·m2/kg. In a single step, antibodies could be readily immobilized onto the surface of the particles with a high binding capacity. The GoldMag particles can be used as a novel carrier in immunoassays. The maximum quantity of human IgG immobilized onto GoldMag particles was 330 μg/mg. In order to validate the quality of the GoldMag particles as immunoassay carriers, an immunoassay system was used. The relative amount of immobilized human IgG was measured by HRP-labeled anti human IgG. The coefficient of variation within parallel samples of each group was below 6% and the coefficient of variation of means between five groups carried out separately was below 7%. Based on the sandwich method, the Hepatitis B surface antigen (HBsAg) and interleukin-8 (IL-8) were also analyzed by qualitative and quantitative detection, respectively. The result indicated that the GoldMag particles with assembled structure were an ideal carrier in immunoassay. 相似文献
3.
Guang Hua Zhu Krystyna Tomsia Hong Yu Motlan Ewa M. Goldys 《中国化学快报》2007,18(5):581-584
Europium ions were chemically bound to CdS nanoparticles surface by diethylenetri-aminepentaacetate (DTPA, 1) in a two-step synthetic route. First 1 was applied to chelate with cadmium on the surface of cadmium-rich CdS nanoparticles and act as a capping agent. Further, the purified 1-capped particles were used to bind with Eu~3 . The purified and redispersed particles were characterized by photoluminescence spectroscopy, TEM and SEM. It was observed that Eu~3 on the nanoparticle surface significantly increased the band gap emission and decreased the surface emission intensity of the CdS nanoparticles. 相似文献
4.
Hui Pan~* Mei Qi Zhi Jun Zhang Laboratory of Special Functional Material Henan University Kaifeng PR China 《中国化学快报》2008,19(4):435-437
The radical polymerization of maleic anhydride(MA),styrene(ST)with the vinyl groups introduced onto the surface of the nano-sized silica via solution polymerization method was developed.The methacryloxypropyl nano-sized silica(MPNS)was used as macromonomer and polymerized with maleic anhydride and styrene by initiating with BPO in toluene.The structure and properties of MPNS/SMA nano-composite were characterized by FT-IR spectra and TEM.Meanwhile,it was applied as tanning agent compared with the traditional styrene-maleic anhydride copolymer in leather.It was found that the applied leather had better quality characteristics with the addition of the nano-sized silica. 相似文献
5.
RongChunXIONG DongZhouYAN GangWEI 《中国化学快报》2003,14(11):1167-1170
Nano-structured SiO2 thin films were prepared on the surface of carbon steel for the first time by LPD. The compositions of the films were analyzed by XPS, and the surface morphology of the thin films were observed by AFM. The thin films were constituted by compact particles of SiO2, and there was no Fe in the films. In the process of film forming, the SiO2 colloid particles were deposited or absorbed directly onto the surface of carbon steel substrates that were activated by acid solution containing inhibitor, and corrosion of the substrates was avoided. The nano-structured SiO2 thin films that were prepared had excellent protective efficiency to the carbon. 相似文献
6.
The surface of calcium carbonate(CaCO_3)particles was modified with stearic acid(SA)and the chemical structures of the product were characterized by FT-IR analysis.The interaction between polydimethylsiloxane(PDMS)and CaCO_3 fillers with different surface character was investigated by means of dynamic rheological and bound rubber tests for uncured compounds and mechanical properties measurements for the corresponding vulcanites.The results of dynamic tests indicate that with the increase of SA mass fract... 相似文献
7.
Surface of TiO2 nanoparticles was modified with the in situ chemical oxidative polymerization of aniline. Polyaniline modified TiO2 nanoparticles (PANI-TiO2 ) were characterized with the FT-IR, XRD, SEM and TEM techniques. Results confirmed that PANI was grafted successfully on the surface of TiO2 nanoparticles, therefore agglomeration of nanoparticles decreased dramatically. Polyvinyl chloride nanocomposites filled with 1 wt% 5 wt% of PANI-TiO2 and TiO2 nanoparticles were prepared via the solution blending method. PVC nanocomposites were analyzed with FT-IR, XRD, SEM, TG/DTA, DSC and tensile test techniques. Effect of PANI as surface modifier of nanoparticles was discussed according to the final properties of PVC nanocomposites. Results demonstrated that deposition of PANI on the surface of TiO2 nanoparticles improved the interfacial adhesion between the constituents of nanocomposites, which resulted in better dispersion of nanoparticles in the PVC matrix. Also PVC/PANI-TiO2 nanocomposites showed higher thermal resistance, tensile strength and Young’s modulus compared to those of unfilled PVC and PVC/TiO2 nanocomposites. 相似文献
8.
Submicron-sized Ag-polypyrrole/poly(styrene-co-methacrylic acid) (Ag-PPy/P(St-co-MAA)) composite particles were fabricated via a redox reaction between pyrrole and AgNO3 in the presence of P(St-co-MAA) soap-free latex. The products are characterized by transmission electron microscopy (TEM), electron diffraction spectra (EDS), Raman spectra, thermogravimetric analysis (TGA) and scanning electron microscopy (SEM). The results showed that Ag-PPy nanocomposites were in situ deposited onto the surface of P(St-co-MAA) latex particles tailored by carboxylic-acid groups. The nanocomposites of Ag-PPy distributed on the surface of polymer particles transformed from discretely dots to continuously coating as the reaction temperature increased from 15℃ to 60℃. Strawberry-like composite particles were obtained at the reaction temperature of 60℃. The TGA characterization confirmed that the Ag-PPy nanocomposites loading onto the P(St-co-MAA) particles were systematically controlled over a range of 6 wt%-42 wt% by changing the reaction temperatures. The fluorescence quenching effect of the Ag-PPy/P(St-co-MAA) composite particles was explored on Rhodamine B as a model molecule with the Stern-Völmer quenching constant KSV of 5.9×104 (g/mL)-1. It is suggested that the fluorescence quenching effect is caused by the resonance energy transfer mechanism. 相似文献
9.
Preparation and characterization of ultrafine Fe-Cu-based catalysts for CO hydrogenation 总被引:1,自引:0,他引:1
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The ultrafine particles of a new style Fe-Cu-based catalysts for CO hydrogenation were prepared by impregnating the organic sol of Fe(OH)3 and Cu(OH)2 onto the activated Al2O3, in which the organic sol of Fe(OH)3 and Cu(OH)2 were prepared in the microemulsion of dodecylbenzenesulfonic acid sodium(S)/n-butanol(A)/toluene(O)/water with V(A)/V(O) = 0.25 and W(A)/W(S) = 1.50. This catalyst was characterized by particle size analysis, XRD and TG. The results of particle size analysis showed that Fe(OH)3 particles with a mean size of 17.1 nm and Cu(OH)2 particles with an average size of 6.65 um were obtained. TG analysis and XRD patterns suggested that 673 K is the optimal calcination temperature. CO hydrogenation produced C+OH with a high selectivity above 58 wt% by using the ultrafine particles as catalyst, and the total alcohol yield of 0.250 g·ml^-1 ·h^-1 was obtained when the contents of Al2O3 and K were 88.61 wt% and 1.60 wt%, respectively. 相似文献
10.
Gas Phase Selective Catalytic Oxidation of Toluene to Benzaldehyde on V2O5-Ag2O/η-Al2O3 Catalyst 总被引:1,自引:0,他引:1
TonglaiZhang LiqiuMao WeihuaLiu 《天然气化学杂志》2004,13(4):238-243
Gas phase selective catalytic oxidation of toluene to benzaldehyde was studied on V2O5-Ag2O/η-Al2O3 catalyst prepared by impregnation. The catalyst was characterized by XRD, XPS, TEM,and FT-IR. The catalytic results showed that toluene conversion and selectivity for benzaldehyde on catalyst sample No.4 (V/(V Ag)=0.68) was higher than other catalysts with different V/Ag ratios. This was attributed to the higher surface area, larger pore volume and pore diameter of the catalyst sample No.4 than the other catalysts. The XRD patterns recorded from the catalyst before and after the oxidation reaction revealed that the new phases were developed, and this suggested that silver had entered the vanadium lattice. XPS results showed that the vanadium on the surface of No.4 and No.5 sample was more than that in the bulk, thus forming a vanadium rich layer on the surface. It was noted that when the catalyst was doped by potassium promoter, the toluene conversion and selectivity for benzalde hydewere higher than those on the undoped catalyst. This was attributed to the disordered structure of V2O5 lattice of the K-doped catalyst and a better interfacial contact between the particles. 相似文献
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12.
Before polymerization, the introduction of double bonds onto the surface of the TiO2 particles was achieved by the treatment of the TiO2 particles with the silane-coupling agent. Via in-situ emulsion polymerization, the poly(methyl methacrylate) (PMMA)/titanium oxide (TiO2) composite particles were prepared by graft polymerization of MMA from the surface of the modified TiO2 particles. The structure of the obtained PMMA/TiO2 composite particles was characterized using fourier transform infrared spectra (FT-IR), thermo-gravimetric analysis (TGA), differential scanning calorimetry (DSC) and size excluding chromatography (SEC). The morphology of the obtained PMMA/TiO2 composite particles was observed by transmission electron microscope (TEM). The results of FT-IR and TGA measurements show that PMMA is successfully grafted from the surface of the TiO2 particles and that the percentage of grafting and the grafting efficiency can reach 208.3% and 96.6%, respectively. At the same time, the TGA and DSC measurements indicate an enhancement of thermal stability. TEM images demonstrate a better dispersion of the TiO2 particles in the composite latex. In addition, UV-visible absorption measurements show that the PMMA/TiO2 composite particles can absorb over 95% UV light at 210–400 nm wavelength. 相似文献
13.
纳米材料的制备、性能与应用已成为近年来的研究热点之一犤1犦。由于在催化、光学和电学材料中的广泛应用,超细单分散的金属微粒的制备与性质已引起人们的广泛兴趣。通常制备金属纳米微粒的方法有两种:一是把固体金属材料分裂为纳米尺寸的颗粒,如机械粉碎、电弧放电及金属原子蒸气沉积犤2犦,用这种方法制备的金属微粒粒径一般都比较大,且粒子尺寸分布宽,另一种是把金属原子制成纳米尺度的颗粒,如乳液聚合法犤3犦、热解犤4犦、γ-射线辐照犤5犦、脉冲电沉积犤6犦和化学还原犤7犦等,这种方法制备的微粒粒径通常分布窄且粒子小… 相似文献
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15.
Micron-sized mono-dispersed polystyrene (PS)/poly(n-butyl methacrylate) (PBMA) composite particles (PS/PBMA=2/1 by weight) having a heterogeneous structure in which many fine
PBMA domains dispersed in a PS matrix near the particle surface were produced by seeded polymerization of n-butyl methacrylate (BMA) of which almost all had been absorbed by 1.8 μm-sized monodispersed PS seed particles utilizing
the dynamic swelling method. The morphology was varied by changing the PS/BMA ratio and polymerization temperature. It was
concluded that the swelling state of 2 μm-sized BMA-swollen PS particles in the seeded polymerization process is one of the
important factors to control the morphology of the composite particles.
Received: 27 November 1996 Accepted: 21 March 1997 相似文献
16.
A direct synthetic route leading to titania particles dispersed on nonporous spherical silica particles has been investigated; 5, 10, and 20% (w/w) titania/silica sols mixtures were achieved via hydrolyzation of titanium tetra-isopropxide solution in the mother liquor of a freshly prepared sol of spherical silica particles (St?ber particles). Titania/silica materials were produced by subsequent drying and calcination of the xerogels so obtained for 3 h at 400 and 600 degrees C. The materials were investigated by means of thermal analyses (TGA and DSC), FT-IR, N(2) gas adsorption-desorption, powder X-ray diffraction (XRD), and transmission electron microscopy (TEM). In spite of the low surface area (13.1 m(2)/g) of the pure spherical silica particles calcined at 400 degrees C, high surface area and mesoporous texture titania/silica materials were obtained (e.g., S(BET) ca. 293 m(2)/g for the 10% titania/silica calcined at 400 degrees C). Moreover, the materials were shown to be amorphous toward XRD up to 600 degrees C, while reasonable surface areas were preserved. It has been concluded that dispersion of titania particles onto the surface of the nonporous spherical silica particles increase their roughness, therefore leading to composite materials of less firm packing and mesoporosity. 相似文献
17.
Core–shell latex particles made of a poly(butyl methacrylate) (PBMA) core and a thin polypyrrole (PPy) shell were synthesized
by two-stage polymerization. In the first stage, PBMA latex particles were synthesized in a semicontinuous process by free-radical
polymerization. PBMA latex particles were labeled either with an energy donor or with an energy acceptor, in two different
syntheses. These particles were used in a second stage as seeds for the synthesis of the core–shell particles. The PPy shell
was polymerized around the PBMA core latex in an oxidative chemical in situ polymerization. Proofs for the success of the
core–shell synthesis were obtained using nonradiative energy transfer (NRET) and atomic force microscopy (AFM). NRET gives
access to the rate of polymer chain migration between adjacent particles in a film annealed at a temperature above the glass-transition
temperature T
g of the particles. Slower chain migration of the PBMA polymer chains was obtained with the PBMA–PPy core–shell particles compared
to rate of the PBMA polymer chain migration found with the pure, uncoated PBMA particles. This result is due to the coating
of PBMA by PPy, which hinders the migration of the PBMA polymer chains between adjacent particles in the film. This observation
has been confirmed by AFM measurements showing that the flattening of the latex film surface is much slower for the core–shell
particles than for the pure PBMA particles. This result can again be explained by the presence of a rigid PPy shell around
the PBMA core. Thus, these two complementary methods have given evidence that real core–shell particles were synthesized and
that the shell seriously hinders film formation of the particles in spite of the fact that it is very thin (thickness close
to 1 nm) compared to the size (750 and 780 nm in diameter) of the PBMA core. Transparency measurements confirm the results
obtained by NRET and AFM. When the films are placed at a temperature higher than the T
g of PBMA, the increase in transparency is faster for films made with the uncoated PBMA particles than for films made with
the coated PBMA particles. This result indicates again that the presence of the rigid PPy layer around the PBMA core reduces
considerably the speed at which the structure of the film is modified when heated above the T
g of PBMA.
Received: 02 September 1999 Accepted: 21 December 1999 相似文献
18.
通过利用偶联剂和超声分散将TiO2表面功能化, 在其表面引入烯键, 与聚N-异丙基丙烯酰胺在交联剂存在下共聚, 制备了不同纳米TiO2含量的聚N-异丙基丙烯酰胺复合水凝胶.采用红外光谱、扫描电镜、紫外光谱、热重分析、动态粘弹谱仪等表征了复合水凝胶的微观结构和形貌, 测试了复合凝胶材料对紫外线的吸收、热稳定性、机械强度及其韧性. 结果表明: 纳米TiO2粒子的引入, 使得复合凝胶材料对紫外线吸收效果显著, 凝胶的稳定性、机械强度及韧性得到明显改善. 相似文献
19.
We report electrochemical preparation and characterization of a new biosensor made of nanostructured titanium dioxide (nano-TiO(2)) particles and deoxyribonucleic acid (DNA). Thionin (TN) redox mediator was electrochemically deposited onto DNA/nano-TiO(2) modified glassy carbon electrode (GCE). The X-ray diffraction analysis, atomic force microscope (AFM) and scanning electron microscope (SEM) were used for surface analysis of TN/DNA/nano-TiO(2) film. In neutral buffer solution, TN/DNA/nano-TiO(2)/GCE biosensor exhibited excellent electrocatalytic activity towards the reduction of hydrogen peroxide (H(2)O(2)) and oxygen (O(2)). The biosensor shows excellent analytical performance for amperometric determination of H(2)O(2), at reduced overpotential (-0.2V). The detection limit and liner calibration range were found to be 0.05mM (S/N=3) and 0.05-22.3mM, respectively. In addition, determination of H(2)O(2) in real samples was carried out using the new biosensor with satisfactory results. The TN/DNA/nano-TiO(2)/GCE showed stable and reproducible analytical performance towards the reduction of H(2)O(2). This biosensor can be used as an amperometric biosensor for the determination of H(2)O(2) in real samples. 相似文献
20.
纳米晶氧化锡的水热合成与表征 总被引:11,自引:0,他引:11
以水热法合成了高比表面积的纳米晶SnO_2粉体,运用FT-IR,XRD,BET,TEM 等手段对粉体的晶化过程进行了分析表征。FT-IR显示120 ℃水热得到的粉体即实 现水合锡化合物的晶化。XRD分析表明所得粉体均匀数纳米,且随水热温度的提高 ,晶粒长大。水热粉体均具有很高的比表面积。TEM显示粉体呈单分散状态。将水 热粉体进行热处理,粉体则长大较快,比表面积降低,分散性能出现反常改善。 相似文献