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Aouada F.A.,Sao Paulo State University | De Moura M.R.,University of Sao Paulo | Orts W.J.,U.S. Department of Agriculture | Mattoso L.H.C.,National Nanotechnology Laboratory for Agriculture
Journal of Agricultural and Food Chemistry | Year: 2011

The main objective of this article was to report a simple, fast, and low cost strategy for the synthesis of micro- and nanocomposites by adding cellulose nanofibers, obtained by acid hydrolysis, and added to hydrogels as reinforcing agents. Specifically, when cellulose nanofibers were added to hydrogels, morphologic analyses showed significant decreases in pore size and formation of three-dimensional well-oriented porous microstructure. It was also observed that cellulose nanoparticles improved the mechanical and structural network properties without negatively impacting their thermal and hydrophilic properties. The value of maximum compressive stress was 2.1 kPa for the PAAm-MC, and it increased to 4.4 kPa when the cellulose nanofiber was incorporated into the hydrogel. By investigation of XRD patterns, it was found that the incorporation of cellulose nanofiber affected the crystallinity of PAAm-MC hydrogels, thus contributing to improvements in mechanical, structural, and hydrophilic properties of the PAAm-MC hydrogels. © 2011 American Chemical Society. Source

Pereira L.,Federal University of ABC | Mafalda R.,Federal University of ABC | Marconcini J.M.,National Nanotechnology Laboratory for Agriculture | Mantovani G.L.,Federal University of ABC
Smart Innovation, Systems and Technologies | Year: 2015

This paper simulates the environmental impact of a design alternative choice based on materials selection. Applying an interdisciplinary research approach, we have used lab results of a nanocomposite material obtained from the mixture with sugarcane bagasse in order to simulate the carbon footprint and energy consumed in a Solidworks Sustainability design experiment. This practice can offer useful insights both for material and design engineers demonstrating quantitative and qualitatively the implications of eco design alternatives in early life cycle, including the life cycle of a new material. © Springer India 2015. Source

Santos A.S.F.,Federal University of Paraiba | Pereira-Da-Silva M.A.,University of Sao Paulo | Pereira-Da-Silva M.A.,Paulista University | Oliveira J.E.,Federal University of Lavras | And 2 more authors.
Journal of Nanoscience and Nanotechnology | Year: 2016

Studies on sonochemical hydrolysis of cellulose have been suggested as an alternative route to obtaining cellulose nanoparticles. In this work, the potential use of acid hydrolysis assisted by sonication to obtain cellulose whiskers was studied. Parameters such as acid concentration, hydrolysis time and temperature were investigated to evaluate their effect on the morphological properties of the nanowhiskers, as compared to the conventional extraction process by acid hydrolysis with mechanical stirring. Morphology and degree of crystallinity of the nanowhiskers were studied by atomic force microscopy (AFM) and X-ray diffraction (XRD). Results indicated that the extraction time was reduced from about 45 min to less than 3 min using the same acid concentration and temperature used in conventional acid hydrolysis treatment. Likewise, it was possible, within the range of 30 min, to extract whiskers at room temperature or using half the concentration of acid by raising the temperature to about 80°C. These are promising results towards a more economically viable and ecologically friendly extraction procedure used to obtain cellulose nanowhiskers, since both extraction time and acid concentration, used in nanowhisker extraction, were significantly reduced by replacing mechanical with sonochemical stirring. Copyright © 2016 American Scientific Publishers All rights reserved. Source

Martelli M.R.,National Nanotechnology Laboratory for Agriculture | Barros T.T.,National Nanotechnology Laboratory for Agriculture | De Moura M.R.,National Nanotechnology Laboratory for Agriculture | De Moura M.R.,University of Sao Paulo | And 2 more authors.
Journal of Food Science | Year: 2013

Puree prepared from over-ripe peeled bananas was used as raw material for films processing in a laboratory padder. Pectin and glycerol as plasticizer were added in small concentrations and chitosan nanoparticles (88.79 ± 0.42 nm medium size) incorporated at 0.2% (dry weight basis) as reinforcement material. The mechanical properties, water vapor transmission, thermal stability, and scanning electron microscopy of fractured film surfaces were characterized. Both pectin and glycerol demonstrated an important role in promoting elongation and film handability as was expected. The incorporation of nanoparticles promoted noticeable improvement of the mechanical properties and acted in reducing the water vapor permeation rate, by 21% for films processed with pectin and up to 38% for films processed without pectin, when compared to the control (puree films with no pectin and nanoparticles additions). Microscopic observation revealed a denser matrix when nanoparticles are incorporated into the films. Practical Application: The development of films from fruit purees head to a new strategy for plastic processing from natural resources. The over-ripe or even waste banana can be adequately prepared for batch films processed with reasonable mechanical and barrier properties, suitable for applications in the food segment. The addition of small fractions of chitosan nanoparticles, form nanocomposites enhancing mechanical and thermal stability broadening potential film applications. © 2012 Institute of Food Technologists®. Source

de Moura M.R.,University of Sao Paulo | de Moura M.R.,National Nanotechnology Laboratory for Agriculture | Aouada F.A.,Sao Paulo State University | Aouada F.A.,National Nanotechnology Laboratory for Agriculture | And 2 more authors.
Polymer - Plastics Technology and Engineering | Year: 2011

In this work, clay-based nanocomposites films were prepared by addition of clay-Na+ natural montmorillonite in pectin and hydroxypropyl methylcellulose (HPMC) matrices. Mechanical (tensile strength, elastic modulus, and elongation) and barrier (Water Vapor Permeability (WVP), and Oxygen permeability (O2P)) properties were investigated. From results, it was observed that the WVP and O2P decreased when nanoclay was included into the HPMC and pectin matrix films. Additionally, the incorporation of nanoclay in the films significantly improved the mechanical properties because the reinforcing effect of clay from its high aspect ratio and its enormous surface area. These results are very important in packaging area. © Taylor & Francis Group, LLC. Source

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