共查询到20条相似文献,搜索用时 15 毫秒
1.
Aslam Khan Abdullah S Aldwayyan Mansour Alhoshan Mohamad Alsalhi 《Polymer International》2010,59(12):1690-1694
Polyaniline (PANI) is a well‐studied material and is the pre‐eminent electrically conducting organic polymer with the potential for a variety of applications such as in batteries, microelectronics displays, antistatic coatings, electromagnetic shielding materials, sensors and actuators. Its good environmental as well as thermal stability and electrical conductivity tunable by appropriate doping make PANI an ideal active material for several applications. In this paper, we report the synthesis of water‐dispersible colloidal PANI/iron oxide composite nanoparticles using an in situ chemical oxidation polymerization method in a micellar medium of sodium dodecylsulfate, where the cores (iron oxide) are embedded in a PANI matrix layer. Transmission electron micrographs showed evidence of the formation of an iron oxide core/PANI shell composite with a thin layer of PANI over the iron oxide cores. The results of thermogravimetric, Fourier transform infrared and UV‐visible analysis indicated that the iron oxide nanoparticles could improve the composite thermal stability possibly due to the interaction between iron oxide particles and PANI backbone. We believe that the synthetic route described can also be adapted for the assembly of hierarchical structures of other metal oxides or hydroxides onto various cores. Copyright © 2010 Society of Chemical Industry 相似文献
2.
Feng Yang Xuequan Zhang Haichao Zhao Bin Chen Baotong Huang Zhiliu Feng 《应用聚合物科学杂志》2003,89(13):3680-3684
Polyethylene (PE)/montmorillonite (MMT) nanocomposites were prepared by in situ coordination polymerization using a MMT/MgCl2/TiCl4 catalyst activated by Al(Et)3. The catalyst was prepared by first diffusing MgCl2 into the swollen MMT layers, followed by loading TiCl4 on the inner/outer layer surfaces of MMT where MgCl2 was already deposited. The intercalation of MMT layers by MgCl2 and TiCl4 was demonstrated by the enlarged interlayer spacing determined by WAXD. The nanoscale dispersion of MMT layers in the polyethylene matrix was characterized by WAXD and TEM. As a consequence, the crystallinity of the nanocomposite decreased sharply, whereas the tensile strength was significantly improved compared to that of virgin polyethylene of comparable molecular weight. The confinement of the nanodispersed MMT layers to molecular chain and the strong interaction between the nanoscale MMT layers and the resin matrix were thought to account for the decrease of crystallinity and the remarkable enhancement of strength. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 3680–3684, 2003 相似文献
3.
Alexandre Carneiro Silvino Kenia Santos de Souza Karim Dahmouche Marcos Lopes Dias 《应用聚合物科学杂志》2012,124(2):1217-1224
Polylactide nanocomposites with organo‐modified montmorillonite presenting a high degree of clay exfoliation were prepared via in situ polymerization by using an improved methodology. The morphology of the nanocomposites was studied by WAXD and SAXS. The size distribution of clay aggregates in the polylactide matrices was quantitatively determined by SAXS applying the stacked‐disk model. The analyses show high degree of delamination of the silicate yielding exfoliated polylactide nanocomposites even at high concentration of clay (>10 wt %). L ‐lactide conversions measured by ATR‐FTIR were determined to be no less than 94% after 3 h of reaction in all polymerizations. DSC measurements were performed to study the influence of the clay content on the thermal behavior of the prepared nanocomposites. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012 相似文献
4.
Well-defined polymer-TiO2 nanocomposites of core–shell structure were prepared by two-steps, surface-initiated atom transfer radical polymerization (ATRP) of styrene and in situ chemical oxidative polymerization of aniline monomers from the surfaces of the TiO2 nanoparticles. The methods used include the following: initially, the ATRP initiator was covalently attached to the surface of TiO2 nanoparticles by esterification of 2-bromo-2-methyl propionic acid with hydroxyl group. The metal-catalyzed radical polymerization of styrene with modified TiO2 nanoparticles was performed using a copper catalyst system to give the TiO2-based core hybrids linking PSt segments (TiO2-PSt hybrids). Next, the TiO2-PSt reacted with HNO3/H2SO4 to produce a nitro group containing polystyrene to form TiO2-PSt-NO2, and obtained TiO2-PSt-NO2 was treated with hydrochloric acid/SnCl2, and converted to an amine group containing polystyrene (TiO2–PSt-NH2). Finally, surface oxidative graft copolymerization of aniline, using the –NH2 moieties of TiO2/PSt-NH2 as the anchoring sites. Characterization of these well-defined nanocomposites included FTIR, thermogravimetric analysis, transmission electron microscopy, and X-ray diffraction. 相似文献
5.
Polytriazole/clay nanocomposites synthesized using in situ polymerization and click chemistry 总被引:1,自引:0,他引:1
Yun-Sheng Ye 《Polymer》2010,51(2):430-1106
6.
Fangfang Wu Yonggen Lu Guilin Shao Fanlong Zeng Qilin Wu 《Polymer International》2012,61(9):1394-1399
Highly oriented molecular structure is essential for high‐performance carbon fibers. The addition of a small amount of graphene sheets may enhance the degree of molecular orientation of precursor fibers during spinning and stabilization by limiting the disorientation of the chain segments. Graphene sheets merge into the carbon fiber structure during carbonization. The structure and properties of polyacrylonitrile containing graphene oxide (GO) prepared by in situ polymerization were investigated. With increasing GO loading, the molecular weight of the polymer decreased gradually from 69 000 g mol?1 for the sample without GO to 60 600 g mol?1 for the sample with 2.5 wt% loading of GO. Scanning electron microscopy and X‐ray diffraction results indicated that GO was dispersed in single layers in the polymer matrix. The degree of crystallization of the polymer with 0.5 wt% GO was increased by 8%. Moreover, differential scanning calorimetry and thermogravimetric analysis showed that an appropriate amount of GO, e.g. 0.5 wt%, made the carbon yield of the polymer increase by 5.0 wt%, because the GO in the composite improved the intermolecular crosslinking reaction. Copyright © 2012 Society of Chemical Industry 相似文献
7.
An ion‐exchange method was applied to replace sodium cations inside the interlamellar space of montmorillonite with positively charged stearyl trimethyl ammonium chloride. The d001‐spacing of montmorillonite is larger in toluene than in other solvents. The overexchanged stearyl methyl ammonium chloride in the montmorillonite layers can be completely washed out by ethanol. Polypropylene–montmorillonite nanocomposites were prepared by using the supported rac‐Et(Ind)2ZrCl2 catalyst on the montmorillonite. The nanocomposites that were polymerized by the supported catalyst were characterized by infrared spectroscopy, nuclear magnetic resonance, X‐ray diffraction, differential scanning calorimetry, scanning electron microscopy, and transmission electron microscopy. Transmission electron microcopy shows that each silicate sheet of montmorillonite is randomly dispersed into the polypropylene matrix following polymerization by using a supported catalyst. The polypropylene nanocomposites had higher crystallinity, hardness, and thermal properties than pure polypropylene. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 95: 1228–1236, 2005 相似文献
8.
Electroconductive performance of polypyrrole/graphene nanocomposites synthesized through in situ emulsion polymerization
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Syed Muhammad Imran Godlisten N. Shao M. Salman Haider Nadir Abbas Manwar Hussain Hee Taik Kim 《应用聚合物科学杂志》2015,132(15)
The present study demonstrates a modified in situ emulsion polymerization (EP) approach convenient for the formation of polypyrrole/graphene (PPy/GN) nanocomposites with harnessed conductivities. A series of PPy/GN nanocomposites were prepared by loading different weight percent (wt %) of GN during in situ EP of pyrrole monomer. The polymerization was carried out in the presence of dodecyl benzene sulfonic acid, which acts as an emulsifier and protonating agent. The microstructures of the nanocomposites were studied by scanning electron microscopy, transmission electron microscopy, X‐ray diffraction, Fourier transform infrared, X‐ray photoelectron spectroscopy, UV–vis spectroscopy, Raman spectroscopy, photoluminescence spectroscopy and thermogravimetric analyses. The electrical conductivities of the nanocomposite pellets pressed at different applied pressures were determined using four probe analyzer. The electrical conductivities of the nanocomposites were considerably enhanced as compared to those of the individual PPy samples pressed at the same pressures. An enhanced conductivity of 717.06 S m?1 was observed in the sample with 5 wt % GN loading and applied pressure of 8 tons. The results of the present study signify that the addition of GN in the PPy polymer harnesses both electrical and thermal properties of the polymer. Thus, PPy/GN nanocomposites with superior properties for various semiconductor applications can be obtained through direct loading of GN during the polymerization process. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41800. 相似文献
9.
A polyamide 6 (PA 6)/silica nanocomposite was obtained through a novel method, in situ polymerization, by first suspending silica particles in ϵ-caproamide under stirring and then polymerizing this mixture at high temperature under a nitrogen atmosphere. The silicas were premodified with aminobutyric acid prior to the polymerization. The effects of the addition of unmodified and modified silicas on the dispersion, interfacial adhesion, isothermal crystallization, and mechanical properties of PA 6 nanocomposites were investigated by using scanning electron microscopy, dynamic mechanical analysis, differential scanning calorimetry, and mechanical tests, respectively. The results show that the silicas dispersed homogeneously in the PA 6 matrix. The addition of silicas increases the glass transition temperature and crystallization rate of PA 6. The mechanical properties such as impact strength, tensile strength, and elongation at break of the PA 6/modified silica nanocomposites showed a tendency to increase and decrease with increase of the silica content and have maximum values at 5% silica content, whereas those of the PA 6/unmodified silica system decreased gradually. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 69: 355–361, 1998 相似文献
10.
Qingjun Ding Baolei Liu Qiang Zhang Qihui He Baixing Hu Jian Shen 《Polymer International》2006,55(5):500-504
In this paper, a new type of organophilic montmorillonite, co‐treated with cetyltrimethyl ammonium bromide (CTAB) and 4,4′‐diphenymethylate diisocyanate (MDI), was modified and applied to prepare polyurethane/montmorillonite nanocomposites via in situ polymerization. The nanoscale montmorillonite layers were exfoliated and dispersed relatively homogeneously in the polyurethane matrix, and characterized by X‐ray diffraction and transmission electron microscopy. The thermal degradation temperature of the nanocomposites increased, as compared with pristine polyurethane. Dynamic mechanical analysis confirmed the constraining effect of exfoliated montmorillonite layers on polyurethane chains, which benefited the increased storage modulus and increased glass transition temperature. Tensile tests showed that the exfoliated nanocomposites were reinforced and toughened by the addition of nanometer‐size montmorillonite layers. Copyright © 2006 Society of Chemical Industry 相似文献
11.
This article focuses on an improved method, i.e., improved in situ polymerization of ε‐caprolactam in the presence of melamine derivatives to prepare flame‐retardant melamine cyanurate/polyamide 6 (MCA/PA6) nanocomposites. The chemical structures of these synthetic flame retardant composites are characterized by Fourier‐transform infrared spectroscopy and X‐ray diffraction. Morphologies, mechanical properties, and thermal properties also are investigated by the use of transmission electron microscopy, mechanical testing apparatus, differential scanning calorimetry, and thermogravimetric analysis, respectively. Through transmission electron microscopy photographs, it can be found that the in situ‐formed MCA nanoparticles with diametric size of less than 50 nm are nanoscaled, highly uniformly dispersed in the PA6 matrix. These nanocomposites, which have good mechanical properties, can reach UL‐94 V‐0 rating at 1.6‐mm thickness even at a relatively low MCA loading level. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009 相似文献
12.
For the preparation of conducting polyaniline (PANI)/nylon composites with high electrical conductivity as well as superior mechanical properties such as flexibility and lightness, PANI/nylon‐6 composite nanofiber webs were prepared via the electrospinning process with a nylon‐6/formic acid polymer solution, and then PANI on the surface of the nylon‐6 electrospun nanofiber webs was chemically polymerized. The electrical conductivity measurements showed that the conductivity of the PANI/nylon‐6 composite electrospun fiber webs was superior to that of PANI/nylon‐6 plain‐weave fabrics because of the high surface‐area/volume ratios. On the other hand, the volume conductivities of the PANI/nylon‐6 composite electrospun fiber webs increased from 0.5 to 1.5 S/cm as the diffusion time increased from 10 min to 4 h because of the even distribution of PANI in the electrospun fiber webs. However, the surface conductivities of the PANI/nylon‐6 composite electrospun fiber webs somewhat decreased from 0.22 to 0.14 S/cm as the diffusion time increased because of PANI contaminated with aniline monomers, aniline oligomers, and some alkyl chains, which served as electrical resistants. These results were confirmed with Fourier transform infrared, electron spectroscopy for chemical analysis, and morphology analysis. It was concluded that the diffusion time for the in situ polymerization of PANI in electrospun fiber webs was optimized at approximately 3 h. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 983–991, 2005 相似文献
13.
This work focuses on the preparation, characterization and electrical conductive properties of intercalated polyaniline/Na-montmorillonite
nanocomposites. These materials consisting of polyaniline and Na-montmorillonite were prepared by oxidative polymerization
with benzoyl peroxide as oxidizing agent. The synthesized nanocomposites were investigated by a series of characterization
techniques; including Fourier transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy, and thermal
analysis. X-ray diffraction and scanning electron microscopy images showed that the polyaniline was inserted into the clay
layers. The modest increase in layer spacing was as much as 0.53 nm. The thermogravimetric analysis and differential thermal
analysis demonstrated the improved thermal stability of the intercalated nanocomposites relative to the pure polyaniline due
to the incorporated Na-montmorillonite. The room temperature electrical conductivity of nanocomposites varied from 1.0 × 10−7 to 5.8 × 10−5 Scm−1. 相似文献
14.
Lala Zhang Yuzi Xiong Encai Ou Zhongming Chen Yuanqin Xiong Weijian Xu 《应用聚合物科学杂志》2011,122(2):1316-1324
Nylon 6/carboxylic acid‐functionalized silica nanoparticles (SiO2‐COOH) nanocomposites were prepared by in situ polymerization of caprolactam in the presence of SiO2‐COOH. The aim of this work was to study the effect of carboxylic silica on the properties of the nylon 6 through the interfacial interactions between the SiO2‐COOH nanoparticles and the nylon 6 matrix. For comparison, pure nylon 6, nylon 6/SiO2 (unmodified) and nylon 6/amino‐functionalized SiO2 (SiO2‐NH2) were also prepared via the same method. Fourier transform infrared spectrometer (FTIR) spectroscopy was used to evaluate the structure of SiO2‐COOH and nylon 6/SiO2‐COOH. The results from thermal gravimetric analysis (TGA) indicated that decomposition temperatures of nylon 6/SiO2‐COOH nanocomposites at the 5 wt % of the total weight loss were higher than the pure nylon 6. Differential scanning calorimeter (DSC) studies showed that the melting point (Tm) and degree of crystallinity (Xc) of nylon 6/SiO2‐COOH were lower than the pure nylon 6. Mechanical properties results of the nanocomposites showed that nylon 6 with incorporation of SiO2‐COOH had better mechanical properties than that of pure nylon 6, nylon 6/SiO2, and nylon 6/SiO2‐NH2. The morphology of SiO2, SiO2‐NH2, and SiO2‐COOH nanoparticles in nylon 6 matrix was observed using SEM measurements. The results revealed that the dispersion of SiO2‐COOH nanoparticles in nylon 6 matrix was better than SiO2 and SiO2‐NH2 nanoparticles. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011 相似文献
15.
R. Y. Suckeveriene G. Mechrez O. Hachamo Filiba S. Mosheev M. Narkis 《应用聚合物科学杂志》2013,128(3):2129-2135
This work describes an empirical study of in situ interfacial dynamic inverse emulsion polymerization process under sonication of aniline in the presence of nine different types of carbon nanotubes (CNT) in toluene. The polymerization method described in this work is simple and very fast (5 min) compared to the other literature reports (3–12 h). During polymerization, CNT are coated with polyaniline (PANI) forming a core‐shell structure of nanowires as evidenced by transmission electron microscopy (TEM) and high‐resolution scanning microscopy (HRSEM). HRSEM images and surface resistivity imply that PANI coating of CNT leads to a remarkable improvement in separation and dispersion of CNT in toluene, which otherwise would have rapidly coagulate and settle. Two of the nine different CNT studied have shown the lowest surface resistivities. Films of uniform thickness were successfully produced (HRSEM of cross‐sections). The effect of film thickness on conductivity and optical properties is reported in the work. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013 相似文献
16.
This article offers a fast and innovative process for carrying out in situ polymerization of pyrrole onto a polyester fabric. This process is based on electrically-assisted chemical vapor polymerization that takes around 180 s to produce an electroconductive fabric with a surface resistance of as low as 70 Ω. The ultrasonication carried out at 20 kHz frequency is quite effective in binding the polymer to the fabric. Fourier-transform infrared spectroscopy and X-ray diffraction studies confirm that the polymer formed is polypyrrole. The application of electric potential across an oxidant-enriched fabric results in polymer add-on of polypyrrole as high as 250%. The amount of polypyrrole formed and the surface resistance of the fabric are found to depend on the potential applied across the fabric. The concentrations of the oxidant and the dopant, the time of polymerization, and the rate of monomer vaporization are found to be critical in deciding the surface resistance of the fabric. 相似文献
17.
This work deals with preparation, characterization, and performance of electro‐conductive yarns prepared by in situ chemical and electrochemical polymerization of pyrrole. Box‐Behnken design in conjunction with response surface analysis has been used to study the electrochemical polymerization process. The effect of electrochemical process parameters on the electrical resistivity has been reported. Further, the electrical and electromechanical behaviour of the electro‐conductive yarns thus produced has also been reported. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011 相似文献
18.
Nowadays, nanocomposites are a special class of materials having unique physical properties and wide application potential in diverse areas. The present research work describes an efficient method for synthesis of a series of polypyrrole/titanium dioxide (PPy/TiO2) nanocomposites with different TiO2 ratios. These nanocomposites were prepared by one‐step in situ deposition oxidative polymerization of pyrrole hydrochloride using ferric chloride (FeCl3) as an oxidant in the presence of ultra fine grade powder of anatase TiO2 nanoparticles cooled in an ice bath. The obtained nanocomposites were characterized by Fourier‐transform infrared (FTIR), thermogravimetric analysis (TGA), X‐ray diffraction (XRD), and scanning electron microscope (SEM) techniques. The obtained results showed that TiO2 nanoparticles have been encapsulated by PPy with a strong effect on the morphology of PPy/TiO2 nanocomposites. Also, the synthesized PPy/TiO2 nanocomposites had higher thermal stability than that of pure PPy. The investigation of electrical conductivity of nanocomposites by four‐point probe instrument showed that the conductivity of nanocomposite at low TiO2 content is much higher than of neat PPy, while with the increasing contents of TiO2, the conductivity decreases. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012 相似文献
19.
Polystyrene (PS)/calcium carbonate (CaCO3) nanocomposites were prepared by in situ polymerization in the presence of maleic anhydride (MA). The composites were characterized by Fourier transform infrared spectra, gel permeation chromatography, differential scanning calorimetry, controlled stress rheometer, scanning electron microscope (SEM), small‐angle X‐ray scattering (SAXS), and mechanical test. Results show that the copolymer of styrene (St) and MA formed during the polymerization acts as a compatibilizer between PS and nanometer calcium carbonate (nano‐CaCO3) particles, resulting in an increase in the glass transition temperature of the composite. The complex modulus and the impact strength of the PS/nano‐CaCO3 composite show an increase with the addition of MA on account of the enhanced interfacial adhesion and the increased molecular weight. SEM and SAXS analyses indicate that a finer dispersion of nanoparticles and an increased homogeneity of the PS/nano‐CaCO3 composites are obtained with application of a small amount of MA. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci., 2013 相似文献
20.
In situ anionic ring opening polymerization is used to prepare monomer casting polyamide 6 (MCPA6)/carbon nanotubes (CNTs) nanocomposites, whereby water is used as auxiliary dispersing agent of hydroxyl functionalized multiwalled carbon nanotubes (MWNTs‐OH) and ε‐caprolactam (CL) monomer. The MWNTs‐OH were dispersed homogenously in MCPA6 matrix when being observed through transmission electron microcopy. The well dispersed MWNTs‐OH existed at the center of many radial texture phases in MCPA6 matrix. Polarizing microscope analysis showed that these radial texture phases were MCPA6 spherulitic crystallities. Differential scanning calorimetry analysis revealed that the crystallization temperature of the MCPA6/MWNTs‐OH nanocomposites had been improved by adding only 0.2 wt % MWNTs‐OH when compared with pure MCPA6. The influence of MWNTs‐OH on the thermal stability of MCPA6 under nitrogen and air environments was also investigated by thermal gravimetric analysis (TGA). © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009 相似文献