National Nanotechnology Laboratory for Agriculture

São Carlos, Brazil

National Nanotechnology Laboratory for Agriculture

São Carlos, Brazil
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Martelli-Tosi M.,University of Sao Paulo | Assis O.B.G.,National Nanotechnology Laboratory for Agriculture | Silva N.C.,University of Sao Paulo | Esposto B.S.,University of Sao Paulo | And 2 more authors.
Carbohydrate Polymers | Year: 2017

This work investigated changes in the chemical composition and structure of soybean straw (SS) treated with alkali (NaOH 5% and 17.5%) and bleached with hydrogen peroxide (H2O2) or sodium hypochlorite (NaOCl). Removal of the amorphous constituents increased the degree of crystallinity and the content of cellulose fibers particularly after reaction with high concentrations of alkali. Treatment with NaOH 17.5% contributed to the allomorph transition from cellulose I to II regardless of the bleaching agent, but H2O2 as bleaching agent promoted more effective delignification. This work also evaluated the potential use of treated and non-treated SS as reinforcement filler in soy protein isolate film (SPI). Films added with treated SS presented higher mechanical resistance, lower elongation at break, and lower solubility in water. Addition of non-treated SS did not affect the properties of the SPI film significantly. The low solubility and the reasonable water vapor permeability of the composite films make them suitable packaging materials for fresh fruit and vegetables. © 2016 Elsevier Ltd

Corradini E.,Federal University of São Carlos | Corradini E.,National Nanotechnology Laboratory for Agriculture | Marconcini J.M.,National Nanotechnology Laboratory for Agriculture | Agnelli J.A.M.,Federal University of São Carlos | Mattoso L.H.C.,National Nanotechnology Laboratory for Agriculture
Carbohydrate Polymers | Year: 2011

Corn gluten meal/starch (CGM/Starch), corn gluten meal/polyvinyl alcohol (CGM/PVAl), and corn gluten meal/poly (hydroxybutyrate-co-hydroxyvalerate) (CGM/PHB-V) blends were prepared in different proportions. Glycerol was used as plasticizer. The blends were prepared by melting in a Haake torque rheometer, followed by hot compression molding. The morphology of the blends containing CGM showed changes as a function of variations in blend composition. Water absorption at equilibrium did not vary to any significant extent in response to the addition of PVAl or Starch to CGM, and decreased with increasing PHB-V content. Tensile tests showed that the addition of PVAl increased the flexibility of the blends, while the presence of PHB-V enhanced their rigidity, but slight changes in mechanical properties were observed with the addition of Starch to CGM. The dynamic mechanical analysis (DMA) results revealed that all the blends exhibited two different glass transitions, one for each component, indicating that these blends are immiscible in the compositional range of this study. © 2010 Elsevier Ltd. All rights reserved.

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®.

Martelli-Tosi M.,University of Sao Paulo | Torricillas M.D.S.,University of Sao Paulo | Martins M.A.,National Nanotechnology Laboratory for Agriculture | Assis O.B.G.D.,National Nanotechnology Laboratory for Agriculture | Tapia-Blacido D.R.,University of Sao Paulo
Journal of Nanomaterials | Year: 2016

This study used commercial enzymes to isolate cellulose nanofibrils (CN) and produce sugars from chemically pretreated soybean straw (SS) (stem, leaves, and pods) by alkali (NaOH 5 or 17.5% v/v at 90°C for 1 h or at 30°C for 15 h) and bleaching (NaClO2 3.3% or H2O2 4%) pretreatments. Depending on the pretreatment applied to the soybean straw, the yield of CN varied from 6.3 to 7.5 g of CN/100 g of SS regardless of the concentration of the alkaline solution (5 or 17.5%). The CN had diameter of 15 nm, measured over 300 nm in length, and had high electrical stability (zeta potentials ranged from -20.8 to -24.5). Given the XRD patterns, the crystallinity index (CrI) of CN ranged from 45 to 68%, depending on the chemical pretreatment the starting material was submitted to. CN obtained from SS treated with NaOH 17.5% and H2O2 (CrI = 45%) displayed better thermal stability probably because a lignin-cellulose complex emerged. The soluble fraction obtained in the first step of CN production contained a large amount of reducing sugars (11.2 to 30.4 g/100 g of SS). SS seems to be a new promising industrial source to produce CN via enzymatic-mechanical treatment, leading to large amounts of reducing sugars for use in bioenergy production. © 2016 Milena Martelli-Tosi et al.

de Moura M.R.,University of Sao Paulo | de Moura M.R.,National Nanotechnology Laboratory for Agriculture | Aouada F.A.,São 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.

Aouada F.A.,São 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.

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.

PubMed | National Nanotechnology Laboratory for Agriculture and University of Sao Paulo
Type: | Journal: Carbohydrate polymers | Year: 2016

This work investigated changes in the chemical composition and structure of soybean straw (SS) treated with alkali (NaOH 5% and 17.5%) and bleached with hydrogen peroxide (H

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.

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