Smart hollow microspheres of chondroitin sulfate conjugates and magnetite nanoparticles for magnetic vector

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Smart hollow microspheres composed of vinyled-chondroitin sulfate conjugates (CS pi) and magnetite nanoparticles were obtained by the intermediate of a multiple emulsion in absence of a surfactant, attributable to stabilizing properties of the CS. It was formed an oil-water multiple emulsion in which the CS played a role as an anionic stabilizer for magnetite nanoparticles via complexation. Iron oxides were bonded to the microspheres by the formation of a complex of Fe(3+) ions on the crystalline phase with oxygen atoms at the carboxyl groups without their magnetic properties being affected. The average crystal size of embedded magnetite nanoparticles was approximately 16.5 nm, indicative of a good dispersion in microspheres. Furthermore, the introduction of iron oxides resulted in microspheres with a higher diameter and a narrower particle size distribution. (C) 2010 Elsevier Inc. All rights reserved.3521107113Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)FAPESP [06/50952-4]CNPq [Proc. 151999/2008-2

Porous nanocomposite hydrogel of vinyled montmorillonite-crosslinked maltodextrin-co-dimethylacrylamide as a highly stable polymer carrier for controlled release systems

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Nanocomposite hydrogel consisting of dispersed montmorillonite-crosslinked maltodextrin-co-dimethylacrylamide (malt-dex-co-DMAAm) as a highly stable device was developed. Carbon-carbon pi-bonds issued from glycidyl methacrylate (GMA) were incorporated onto both the MMT (MMT-pi) and the malt-dex (malt-dex-pi) structures. The nanocomposite copolymer hydrogel was processed via radical crosslinking reaction of malt-dex-pi with MMT-pi in the presence of DMAAm. The radical reaction of the carbon-carbon pi-bonds at the MMT-pi was verified by treating the MMT-pi with sodium persulfate. There was an excellent dispersion of the MMT-pi at the interior of the matrix even after the nanocomposite hydrogel being swollen, demonstrating that the developed methodology can imprint stability of mineral nanoparticles into a porous polymer network preventing diffusion of water-bonded silicate platelets toward the outside matrix. The water absorption profile became more dependent on the polymer relaxation for mineral-loader nanocomposite hydrogels. Higher water absorption had an impact on reduction of elasticity modulus due to softer polymer network in swollen state. (C) 2010 Elsevier Ltd. All rights reserved.46714651474Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)FAPESP [06/50952-4

Copolymer Hydrogel Microspheres Consisting of Modified Sulfate Chondroitin-co-Poly(N-isopropylacrylamide)

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Modified chondroitin sulfate (pi-CdS) microspheres were synthesized by way of crosslinking-copolymerization reaction with N-isopropylacrylamide (NIPAAm), yielding CdS-co-PNIPAAm copolymer network. The incorporation of vinyl groups onto the CdS was processed with the use of glycidyl methacrylate (GMA) in an aqueous solution of pH 3.5 under stirring speed of 800 rpm at 50 degrees C. C-13 NMR and H-1 NMR spectra of CdS treated with the GMA indicated the formation of 3-methacryloyl-1-glyceryl ester of pi-CdS and 3-methacryloyl-2-glyceryl ester of pi-CdS that are the reaction products resultant of an epoxide ring-opening mechanism via. The synthesis of microspheres was performed via radical reaction of the vinyl groups at the pi-CdS with vinyl groups at the NIPAAm in a water-benzyl alcohol microemulsion. The formation of spherical structures is the result of the polymerization-crosslinking reaction of the pi-CdS with the NIPAAm monomers at the droplets of water, in view that both reactants have hydrophilic characteristics at the temperature at which the reaction was processed. The pure CdS hydrogel microspheres showed a slightly cracked structure with a lower diameter range while the CdS-co-PNIPAAm hydrogel microspheres showed a flat and tight structure with a more regular mass distribution. (C) 2011 Wiley Periodicals, Inc. J Appl Polym Sci 121: 2726-2733, 2011121527262733Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)CNPq [151999/2008-2]FAPESP [06/50952-4

Low-resistance films of polyimides with impregnated copper sulfide

Surface modification of polyimides has been used to obtain better interaction with an inorganic material. Copper sulfide incorporation onto the surface of commercial Kapton (R) polyimide showed that treatment with base was necessary for adherence of the copper sulfide to the polymeric matrix. The optimized conditions for composite preparation, obtained by response surface methodology, was pH 1.4 at 80 degreesC for 3.67 h. Using these conditions, we obtained electrical resistance as low as 1.0 ohm for CuS\Kapton (R) composites. These optimized conditions were used to prepare other low-resistance polyimide composites. The resulting composites were analyzed by photoelectron spectroscopy. The presence of S(2p) and Cu(2p) peaks demonstrated the incorporation of copper sulfide onto the polyimide surface. Scanning electron microphotographs and the images from atomic force microscopy showed a homogeneous CuS distribution in all composites.o TEXTO COMPLETO DESTE ARTIGO, ESTARÁ DISPONÍVEL À PARTIR DE AGOSTO DE 2015.16113097310