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- ItemSomente MetadadadosMultifunctional green nanostructured composites: preparation and characterization(Iop Publishing Ltd, 2018) Montagna, Larissa Stieven [UNIFESP]; Oishi, Silvia Sizuka; Diniz, Milton Faria; Montanheiro, Thais Larissa do Amaral [UNIFESP]; Silva, Fabio Santos; Passador, Fabio Roberto [UNIFESP]; Rezende, Mirabel Cerqueira [UNIFESP]The present research had as main purpose to develop and characterize multifunctional green nanocomposites based on poly(furfuryl alcohol) resin (PFA bioresin), derived from sugarcane bagasse reinforced with different contents of graphite nanosheets (GNS) (0.5, 1.0, 1.5 and 2.0 wt%) which were dispersed in PFA bioresin using an ultrasonic processor. The mixture was poured into silicone molds and cured at room temperature during 24 h followed by a post-cure at preheated oven in cycles of different temperatures. TEM analysis of GNS showed this filler consist of ultrathin and layered sheets. SEM micrographs of the cryogenic fracture of the nanocomposite presented the good interfacial adhesion between PFA bioresin and GNS. Moreover, upon GNS addition in the PFA bioresin, PFA/GNS nanocomposites demonstrated superior mechanical performance and better electrical conductivity than neat PFA bioresin.
- ItemSomente MetadadadosProcessing and characterization of composites of poly(3-hydroxybutyrate-co-hydroxyvalerate) and lignin from sugar cane bagasse(Sage Publications Ltd, 2012-02-01) Camargo, Francisco A.; Innocentini-Mei, Lucia H.; Lemes, Ana Paula [UNIFESP]; Moraes, Sandra G.; Duran, Nelson; Universidade Estadual de Campinas (UNICAMP); Universidade Federal de São Paulo (UNIFESP); Univ Metodista PiracicabaA biodegradable polymer composite containing lignin from sugarcane bagasse and poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) was produced and characterized in terms of its thermal, morphological, and mechanical properties. for comparison with the properties of the composites, the properties of the isolated composite components (lignin and PHBV) were also determined. the characterizations were carried out by Fourier transformed infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), scanning electron microscopy (SEM) and mechanical properties. in the micrograph images, no physical contact between filler and matrix was verified. the thermal decomposition profiles of composites depend on the lignin/PHBV proportions, and their residual mass increased as a function of lignin amount. Higher temperatures were necessary to promote PHBV crystallization in the presence of lignin. However, the crystalline degree of composites was not affected by the lignin. the results obtained in the mechanical tests showed that the lignin addition caused a decrease of mechanical properties.
- ItemSomente MetadadadosPurification, biochemical and functional characterization of miliin, a new thiol-dependent serine protease isolated from the latex of Euphorbia milii(Bentham Science Publ Ltd, 2008-07-01) Moro, L. P.; Murakami, M. T.; Cabral, H.; Vidotto, A.; Tajara, E. H.; Arni, R. K.; Juliano, L. [UNIFESP]; Bonilla-Rodriguez, G. O.; UNESP; Ctr Struct Mol Biol; Universidade de São Paulo (USP); Universidade Federal de São Paulo (UNIFESP)Miliin, a new thiol-dependent serine protease purified from the latex of Euphorbia milii possesses a molecular weight of 79 kDa, an isoelectric point of 4.3 and is optimally active at 60 degrees C in the pH range of and 7.5-11.0. Activity tests indicate that milliin is a thiol-dependent serine protease.
- ItemSomente MetadadadosStructural, morphological, and thermal characterization of kraft lignin and its charcoals obtained at different heating rates(Iop Publishing Ltd, 2018) Brazil, Tayra Rodrigues [UNIFESP]; Costa, Rogeria Nunes [UNIFESP]; Massi, Marcos [UNIFESP]; Rezende, Mirabel Cerqueira [UNIFESP]Biomass is a renewable resource that is becoming more import due to environmental concerns and possible oil crisis. Thus, optimizing its use is a current challenge for many researchers. Lignin, which is a macromolecule with complex chemical structure, valuable physicochemical properties, and varied chemical composition, is available in large quantities in pulp and paper companies. The objective of this work is the physicochemical characterization of two Kraft lignin samples with different purities, and the study of its thermal conversion into charcoal. The lignin characterization was based on chemical, TGA, DSC, FT-IR, particle sizes, and FEG-SEM analyses. These analyses show that the lignins are mainly composed of guaiacyl and syringyl units, with residues of 30-36 wt.%, in inert atmosphere, depending on the lignin purity. From these results, the more purified lignin with higher carbon yield (%C) was selected for charcoal production. The heat treatment (HT) for carbonization of lignin, at different times (90, 180, and 420 min), resulted in different %C (41-44 wt.%). Longer HT resulted in higher %C and in charcoals with smaller pore sizes. Nanopores (similar to 50 nm) are observed for the charcoal obtained with the longest HT.
- ItemSomente MetadadadosSynthesis and Characterization of Fe3O4 Nanoparticles with Perspectives in Biomedical Applications(Univ Fed Sao Carlos, Dept Engenharia Materials, 2014-05-01) Mamani, Javier Bustamante; Gamarra, Lionel Fernel [UNIFESP]; Brito, Giancarlo Esposito de Souza; Hosp Israelita Albert Einstein HIAE; Universidade Federal de São Paulo (UNIFESP); Fac Ciencias Med Santa Casa São Paulo FCMSCSP; Universidade de São Paulo (USP)Nowadays the use of magnetic nanoparticles (MNP) in medical applications has exceeded expectations. in molecular imaging, MNP based on iron oxide coated with appropriated materials have several applications in vitro and in vivo studies. for applications in nanobiotechnology these MNP must present some characteristics such as size smaller than 100 nanometers, high magnetization values, among others. Therefore the MNP have physical and chemical properties that are specific to certain studies which must be characterized for quality control of the nanostructured material. This study presents the synthesis and characterization of MNP of magnetite (Fe3O4) dispersible in water with perspectives in a wide range of biomedical applications. the characterization of the colloidal suspension based on MNP stated that the average diameter is (12.6 +/- 0.2) nm determined by Transmission Electron Microscopy where the MNP have the crystalline phase of magnetite ( Fe3O4) that was identified by Diffraction X-ray and confirmed by Mossbauer Spectroscopy. the blocking temperature of (89 +/- 1) K, Fe3O4 MNP property, was determined from magnetic measurements based on the Zero Field Cooled and Field Cooled methods. the hysteresis loops were measured at different temperatures below and above blocking temperature. the magnetometry determined that the MNP showed superparamagnetic behavior confirmed by ferromagnetic resonance.
- ItemSomente MetadadadosTheoretical study of the XP3 (X = Al, B, Ga) clusters(Elsevier B.V., 2012-05-03) Ueno, Leonardo T.; Lopes, Cinara; Malaspina, Thaciana [UNIFESP]; Roberto-Neto, Orlando; Canuto, Sylvio; Machado, Francisco B. C.; Universidade de São Paulo (USP); Universidade Federal de Uberlândia (UFU); Inst Tecnol Aeronaut; Universidade Federal de São Paulo (UNIFESP); Inst Estudos AvancadosThe lowest singlet and triplet states of AlP3, GaP3 and BP3 molecules with C-s, C-2v and C-3v symmetries were characterized using the B3LYP functional and the aug-cc-pVTZ and aug-cc-pVQZ correlated consistent basis sets. Geometrical parameters and vibrational frequencies were calculated and compared to existent experimental and theoretical data. Relative energies were obtained with single point CCSD(T) calculations using the aug-cc-pVTZ, aug-cc-pVQZ and aug-cc-pV5Z basis sets, and then extrapolating to the complete basis set (CBS) limit. (C) 2011 Elsevier B.V. All rights reserved.