Control of nanoparticle size of fillers by polymer blend technique
TL;DR: In this article, a new technique based on matrix mediated control of growth and morphology using polymer blends was used to obtain nanosize particles of calcium phosphate. But their crystal structure and size were confirmed by X-ray diffraction and electron microscopy.
About: This article is published in Polymer.The article was published on 2001-03-01. It has received 20 citations till now. The article focuses on the topics: Polymer blend & Particle size.
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TL;DR: Hybrid composite coatings containing zinc oxide (ZnO) and polyaniline (PANI) as nano-additives dispersions were prepared with poly(vinyl acetate) (PVAc) as the major matrix.
101 citations
TL;DR: In this article, X-ray diffraction (XRD) and transmission electron microscopy (TEM) techniques were used for the characterization of polystyrene with calcium phosphate nanoparticles.
50 citations
TL;DR: In this article, microbially synthesized magnetite nanoparticles were functionalized with Pd(0), creating a highly reactive, magnetically recoverable, nano-scale catalyst (Pd-BnM).
Abstract: Palladium catalysts offer the potential for the effective treatment of a variety of priority reducible pollutants in natural waters. In this study, microbially synthesized magnetite nanoparticles were functionalized with Pd(0), creating a highly reactive, magnetically recoverable, nano-scale catalyst (Pd-BnM). This was then investigated for the treatment of model Cr(VI) contaminated solutions at a range of pH values, and also alkaline Cr(VI) contaminated leachates from chromite ore processing residue (COPR); a contaminant issue of global concern. The sample of COPR used in this study was obtained from a site in Glasgow, UK, where extensive Cr(VI) contamination has been reported. In initial experiments Pd-BnM was supplied with H2 gas or formate as electron donors, and Cr(VI) removal from model synthetic solutions was quantified at various pH values (2–12). Effective removal was noted at neutral to environmentally relevant alkaline (pH 12) pH values, while the use of formate as an electron donor resulted in loss of performance under acidic conditions (pH 2). Reaction kinetics were then assessed with increasing Pd-BnM loading in both model pH 12 Cr(VI) solutions and the COPR leachate. When formate was used as the electron donor for Pd-BnM, to treat COPR leachate, there was significant inhibition of Cr(VI) removal. In contrast, a promotion of reaction rate, was observed when H2 was employed. Upon sustained reaction with model Cr(VI) solutions, in the presence of excess electron donor (formate or H2), appreciable quantities of Cr(VI) were removed before eventual inactivation of the catalyst. Faster onset of inactivation was reported in the COPR leachates, removing 4% and 64% of Cr(VI) observed from model Cr(VI) solutions, when formate and H2 were used as electron donors, respectively. XAS, TEM-EDX and XPS analysis of the catalysts that had been inactivated in the model solution, showed that the surface had an extensive covering of reduced Cr(III), most likely as a CrOOH phase. COPR reacted catalysts recorded a lower abundance of Cr(III) alongside a high abundance of the leachate components Ca and Si, implicating these elements in the faster onset of inactivation.
38 citations
Cites methods from "Control of nanoparticle size of fil..."
...Further to this, a novel whole-cell mediated method was developed; using a model Fe(III)-reducing bacterium to reduce an Fe(III) oxyhydroxide, producing nano-scale magnetite with a narrow size distribution with controllable reactivity and particle size [27]....
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TL;DR: In this paper, the effect of filler content both nano-and micro-level on the nanostructure and properties of the filler CaCO3 (micro and nano) and the matrix poly(vinyl chloride) (PVC) was reported.
Abstract: Calcium carbonate was synthesized by in situ deposition technique and its nano size (35–60 nm) was confirmed by transmission electron microscopy (TEM). Composites of the filler CaCO3 (micro and nano) and the matrix poly(vinyl chloride) (PVC) were prepared with different filler loadings (0–5 wt%) by melt intercalation. Brabender torque rheometer equipped with an internal mixer has been used for preparation of formulations for composites. The effect of filler content both nano- and micro level on the nanostructure and properties is reported here. The nanostructures were studied by wide angle X-ray diffraction and scanning electron microscopy. The mechanical, thermal, and dynamic mechanical properties of PVC/micro- and nano-CaCO3 composites were characterized using universal testing machine, thermogravimetric analyzer, and dynamic mechanical analyzer. The results of thermal analysis indicated that the thermal stability of PVC/nano-CaCO3 composites was improved as compared with corresponding microcomposites, and that of pristine PVC and maximum improvement was obtained at 1 and 3 phr loadings. However, the tensile strength decreased significantly with increase loading of both nano- and micro-CaCO3, whereas storage modulus and glass transition temperature increased significantly.
27 citations
TL;DR: In this article, a wide and small-angle X-ray scattering intensities (SAXS and WAXS) were recorded by transmission mode on test bars cut from compression-molded plaques tilted by different angles with respect to the plane of the plaque.
Abstract: Nanocomposites formed from organically modified montmorillonite and poly(ethylene-co-vinyl acetate) were studied by X-ray diffraction techniques. Wide- and small-angle X-ray scattering intensities (SAXS and WAXS) were recorded by transmission mode on test bars cut from compression-molded plaques tilted by different angles with respect to the plane of the plaque. The height of the Bragg peaks characteristic of intercalated particles reduced to the baseline at tilt angles greater than 30°. Guinier analysis of the SAXS characteristic of particle scattering showed a radius of gyration of 0.69 nm and the scattering intensity was slightly dependent on the tilt angle. Recording of WAXS in the usual (i.e., in reflective) mode enhanced the effect of the structural features of the surface area and showed much higher degree of intercalation and particle size of the scattering particles than that in transmission mode.
22 citations
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TL;DR: A polyimide hybrid with montmorillonite clay mineral has been synthesized from a dimethylacetamide (DMAC) solution of poly(amic acid) and a DMAC dispersion of montmoroniite intercalated with an ammonium salt of dodecylamine as mentioned in this paper.
Abstract: A polyimide hybrid with montmorillonite clay mineral has been synthesized from a dimethylacetamide (DMAC) solution of poly(amic acid) and a DMAC dispersion of montmorillonite intercalated with an ammonium salt of dodecylamine. Montmorillonite consists of stacked silicate sheets about 2000 A in length, 10 A in thickness. In this hybrid, montmorillonite is dispersed homogeneously into the polyimide matrix and oriented parallel to the film surface. Thanks to this special structure, this hybrid showed excellent gas barrier properties. Only 2 wt % addition of montmorillonite brought permeability coefficients of various gases to values less than half of those of ordinary polyimide. Furthermore, this hybrid had low thermal expansion coefficient. © 1993 John Wiley & Sons, Inc.
1,387 citations
TL;DR: In this paper, the dispersibility of 10-A-thick silicate layers of the clays in the hybrid was investigated by using a transmission electron microscope and X-ray diffractometer.
Abstract: Polypropylene (PP)−clay hybrids (PPCH) have been prepared by simple melt-mixing of three components, i.e., PP, maleic anhydride modified polypropylene oligomers (PP-MA), and clays intercalated with stearylammonium. The dispersibility of 10-A-thick silicate layers of the clays in the hybrids was investigated by using a transmission electron microscope and X-ray diffractometer. It is found that there are two important factors to achieve the exfoliated and homogeneous dispersion of the layers in the hybrids: (1) the intercalation capability of the oligomers in the layers and (2) the miscibility of the oligomers with PP. Almost complete hybrids were obtained in the case where the PP-MA has both intercalation capability and miscibility. The hybrids exhibit higher storage moduli compared to those of PP especially in the temperature range from Tg to 90 °C. The highest relative storage modulus at 80 °C of the hybrid based on a mica and the miscible PP-MA is as high as 2.0 to that of PP and is 2.4 to that of the ...
1,379 citations
TL;DR: In this article, a polymer-ceramic nanocomposite was synthesized consisting of well-dispersed, two-dimensional layers of an organically modified mica-type silicate (MTS) within a degradable poly(e-caprolactone) matrix.
Abstract: A new polymer-ceramic nanocomposite has been synthesized consisting of well-dispersed, two-dimensional layers of an organically modified mica-type silicate (MTS) within a degradable poly(e-caprolactone) matrix. A protonated amino acid derivative of MTS was used to promote delamination/dispersion of the host layers and initiate ring-opening polymerization of e-caprolactone monomer, resulting in poly(e-caprolactone) chains that are ionically bound to the silicate layers. The polymer chains can be released from the silicate surface by a reverse ion-exchange reaction and were shown to be spectroscopically similar to pure poly(e-caprolactone). Thick films of the polymer nanocomposite exhibit a significant reduction in water vapor permeability that shows a linear dependence on silicate content. The permeability of nanocomposite containing as low as 4.8% silicate by volume was reduced by nearly an order of magnitude compared to pure poly(e-caprolactone)
1,223 citations
TL;DR: In this article, a new class of polyimide/silica composites with chemical bonds between the polyimides and silica network has been synthesized by the sol−gel reaction and characterized.
Abstract: A new class of polyimide/silica composites with chemical bonds between the polyimide and silica network has been synthesized by the sol−gel reaction and characterized. The hybrid composite films were obtained by the hydrolysis and polycondensation of (3-aminopropyl)triethoxysilane (APTES) and tetraethoxysilane (TEOS) in N,N-dimethylacetamide solution (DMAc), followed by heating at 100, 200, and 300 °C. The presence of chemical bonds between polyimide (PI) and silica has great effect on the properties of polyimide films, especially on their mechanical properties. The modulus and ultimate strength of the hybrid composite films increased and elongation at break decreased with increased silica content. These hybrid films showed no apparent decrease in thermal decomposition temperature.
325 citations