On the physico-chemical and dielectric properties of glutaraldehyde crosslinked galactomannan–collagen films

Figueiró, S.D.; Góes, J.C.; Moreira, Renato de Azevedo; Sombra, A. S. B.

doi:10.1016/j.carbpol.2004.01.011

Cited by 185 publications

(120 citation statements)

References 8 publications

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“…The crystalline phase obtained from the YIG powder was identified by comparing the diffractograms from the ICDD database (ICDD/PDF-70-0953), see Figure 3. One can observe in F sample an amorphous phase characteristic to the matrix polymer and this pattern follows those observed in the literature [18][19][20][21][22]. This behavior is present in all composites, see FY 25 and FY 50 ( Figure 3).…”

Section: Resultssupporting

confidence: 87%

“…The YIG stability along the frequency analyzed is a characteristic that may be incorporated to the composites. The literature data report cases of increase [33] and decrease [18] of the #$ r , depending on the cross-linker agent and the polymeric material employed. This happens due to density, that is dependent on the material Figures 8a and b suggest the obtaining of a soft ferrimagnetic composite, because the samples are very sensitive to an external magnetic field and reached their saturation magnetization (M S ) with application of relatively small magnetic fields.…”

Section: Resultsmentioning

confidence: 99%

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Microstructure and magneto-dielectric properties of the chitosan/gelatin-YIG biocomposites

Mallmann¹,

Góes²,

Figueiró³

et al. 2011

Express Polym. Lett.

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Abstract. This work is devoted to the preparation of yttrium iron garnet (YIG) ferrimagnetic biocomposites based in biodegradable chitosan and gelatin. The aim was to produce composite films containing controlled amounts of YIG to obtain a new biological material with magneto-dielectric features. Structural characterization of the biocomposites was made by scanning electron microscopy, X-ray diffraction, infrared absorption spectroscopy and thermal analysis, while the dielectric and magnetic properties were obtained from dielectric spectroscopy and magnetic hysteresis loops, respectively. The versatility of the films obtained makes them possible candidates for use as biomaterials or electronic device.

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Section: Resultssupporting

confidence: 87%

Section: Resultsmentioning

confidence: 99%

Microstructure and magneto-dielectric properties of the chitosan/gelatin-YIG biocomposites

Mallmann¹,

Góes²,

Figueiró³

et al. 2011

Express Polym. Lett.

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“…Natural gums usually contain fractions of sugar acid units which would usually impart a weakly anionic character to the gum macromolecule (Wang, Ellis, Ross-Murphy, 2003). Absorption bands around 1618 and 1430 cm -1 are typical of carboxylate groups of the galacturonic acid residues as reported by Okafor, Chukwu, Udeala, (2001) and Figueiro et al, (2004). The region between 1500 and 1800 cm -1 is typically used to detect presence of carboxylic groups.…”

Section: Fourier Transform Analysismentioning

confidence: 99%

Physico-chemical and structural characterization of mucilage isolated from seeds of Diospyros melonoxylon Roxb.

Singh¹,

Bothara²

2014

Braz. J. Pharm. Sci.

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Mucilage was isolated from the seeds of Diospyros melonoxylonRoxb., a plant growing naturally in the forests of India. Various physico-chemical methods like particle analysis, scanning electron microscopy, differential scanning calorimetry, differential thermal analysis, thermogravimetry analysis, molecular weight by gel permeation chromatography, rheometry, elemental analysis, x-ray diffraction spectrometry, zeta potential, fourier transform infrared spectroscopy, 1D(1H and 13C) (NMR) have been employed to characterize this gum in the present study. Particle analyses suggest that mucilage had particle size in nanometer. SEM analysis suggested that the mucilage had irregular particle size. The glass transition temperature of the gum observed was 78 °C and 74 °C by DSC and DTA respectively. The Thermogravimetry analysis suggested that mucilage had good thermal stability with two stage decomposition. The molecular weight of mucilage was determined to be 8760, by gel permeation chromatography, while the viscosity of mucilage was observed to be 219.1 cP. The XRD pattern of the mucilage indicated a complete amorphous nature. Elemental analysis of the gum revealed specific contents of carbon, hydrogen, nitrogen and sulfur. The major functional groups identified from FT-IR spectrum include 3441 cm-1 (-OH), 1632 cm-1 (-COO-), 1414 cm-1 (-COO-) and 1219 cm-1 (-CH3CO). Analysis of mucilage by paper chromatography and 1D NMR indicated the presence of sugars.

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“…As atribuições "no plano" ou "fora do plano" referem-se ao plano do anel benzeno. 2 A atribuição "deformação" ("bending") referese à deformação angular. Se "scissoring" ou "rocking" (deformações no plano), "wagging" ou "twisting" (deformações fora do plano), não se pode precisar na literatura.…”

Section: Estudo Da Eletroatividade Dos Filmes Contendo Gomas Naturaisunclassified

Nanocompósitos eletroativos de poli-o-metoxianilina e polissacarídeos naturais

Eiras¹,

Passos²,

Brito³

et al. 2007

Quím. Nova

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Recebido em 27/6/06; aceito em 8/12/06; publicado na web em 30/7/07 ELECTROACTIVE NANOCOMPOSITES MADE OF POLY(O-METHOXYANILINE) AND NATURAL POLYSACCHARIDES.In this work we take advantage of the polyelectrolyte character of some Brazilian native gums to fabricate electrically conductive, nanostructured films. The gums Sterculia urens, (caraia), Sterculia striata (chicha) or Anadenanthera macrocarpa Benth were assembled in conjunction with poly(o-methoxyaniline) (POMA) in the form of layered nanostructured films using the layer-bylayer (LbL) technique. All the LbL films displayed a well-defined electroactivity, as confirmed via cyclic voltammetry. In comparison to POMA LbL films fabricated with conventional polyelectrolytes (viz. poly(vinyl sulfonic acid)-PVS), the presence of the gums in the LbL films increased remarkably the electrochemical stability of the films.Keywords: natural gums; poly-o-methoxyaniline; layer-by-layer films. INTRODUÇÃOPolissacarídeos naturais têm sido amplamente investigados nos últimos anos em relação às suas características físico-químicas e aplicações. Algumas de suas propriedades são biodegrabilidade, abundância na natureza e versatilidade de aplicações em engenharia, biotecnologia e medicina, além de serem geralmente atóxicos. A formação de filmes finos de polissacarídeos sobre superfícies sólidas pode gerar nova aplicação em sensores ou biossensores. Filmes de quitosana 1 , galactomananas 2 e de carboximetilcelulose 3 vêm sendo usados para fins variados. As gomas naturais são polissacarídeos obtidos de exsudatos de tronco de árvore, sementes, algas ou por fermentação microbiológica. Esses materiais podem ser hidratados em água fria ou quente formando dispersões coloidais, soluções altamente viscosas ou até mesmo géis. Os exsudatos são obtidos do tronco de árvores como resposta do mecanismo de proteção da planta 4,5 . A liberação do exsudato ocorre de forma espontânea ou exploratória, como é o caso do látex da seringueira. Condições climáticas desfavoráveis e solos pobres também estimulam esta produção 4,5 . No entanto, a formação de exsudato pode também ser causada pela indução de agentes químicos, como o óxido de etileno e derivados de ácido benzóico.A árvore angico (Anadenanthera macrocarpa Benth) pertence à família das leguminosas e exsuda uma goma com as mesmas características das gomas arábica (Acacia senegal) e do cajueiro (Anacardium occidentale). A composição da goma do angico, um heteropolissacarídeo, contém arabinose (67,8%), galactose (24,1%), ácido urônico (5,9%) e traços de ramnose, além de apresentar baixa viscosidade, semelhante às gomas do cajueiro e arábica 6,7 . A goma extraída da árvore do chichá (Strerculia striata) é encontrada no norte e no nordeste do Brasil. As gomas obtidas das árvores da família das Sterculias são conhecidas por apresentarem teores elevados de ácidos e alta viscosidade, além de serem capazes de formar géis em água. Um exemplo da goma que apresenta estas características é a exsudada pela árvore caraia (Sterculia urens), nativa da Índia, utili...

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On the physico-chemical and dielectric properties of glutaraldehyde crosslinked galactomannan–collagen films

Cited by 185 publications

References 8 publications

Microstructure and magneto-dielectric properties of the chitosan/gelatin-YIG biocomposites

Microstructure and magneto-dielectric properties of the chitosan/gelatin-YIG biocomposites

Physico-chemical and structural characterization of mucilage isolated from seeds of Diospyros melonoxylon Roxb.

Nanocompósitos eletroativos de poli-o-metoxianilina e polissacarídeos naturais

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