LUIZ GUSTAVO HIROKI KOMATSU

LUIZ GUSTAVO HIROKI KOMATSU

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Study of the incorporation of TiO2/Ag nanoparticles in polyamide by casting method aiming for biocide application
2021 - VECCHIA, MARIA E.K.D.; ZAINE, MARIANA A.; KOMATSU, LUIZ G.H.; DIPOLD, JESSICA; FREITAS, ANDERSON Z.; WETTER, NIKLAUS; PARRA, DUCLERC F.
This study consists in the characterization of polyamide (PA6) films charged with different concentrations of silver nanoparticles deposited in titanium dioxide (TiO2) carrier. The silver nanoparticles were synthesized according to the method adapted from Turkevich using a titanium dioxide carrier and inserted, by suspension, in a polyamide solution. The preparation of PA: AgNp films was performed by the casting method by the dissolution of PA pellets in formic acid. The analysis and characterization of the films by the XRD, DSC, TGA and Raman confocal techniques indicated incorporation of nanoparticles into the polymers, a second thermogravimetric decomposition event as the concentration of AgNp-TiO2 increased and there was no significant change in crystallinity.
Preparation of irradiated silver nanoparticles for polypropylene nanocomposites with pineapple fiber
2021 - ZAINE, M.A.; DALLA VECCHIA, M.E.K.; KOMATSU, L.G.H.; OLIANI, W.L.; PARRA, D.F.
Films of polyethylene-AgNPs
2019 - OLIANI, WASHINGTON L.; KOMATSU, LUIZ G.H.; LUGAO, ADEMAR B.; PARRA, DUCLERC F.
In recent years, antimicrobial packaging has attracted much attention from the food industry because of the increase in consumer demand for minimally processed, preservative-free-products. Different grades of polyethylene, LLDPE and LDPE play a major role in the film blowing industry and are widely used for packing applications. In our study, blown films of LLDPE / LDPE, and their blends were produced using a twin screw extruder. The combination of PEs as matrix, and silver nanoparticles with oleic acid solution, improved the AgNPs dispersion in the films. The films were evaluated by Scanning Electron Microscopy (SEM), Energy Dispersive Spectroscopy (EDX), and Ecotoxicity. Further, the antibacterial properties of the films were investigated against Escherichia coli (Gram-negative) and Staphylococcus aureus (Gram-positive) bacteria.
Aplicação de ZnO como carregador de prata em uma blenda de HMSPP/SEBS visando ação biocida
2019 - KOMATSU, LUIZ G.H.; OLIANI, WASHINGTON L.; LUGAO, ADEMAR B.; PARRA, DUCLERC F.
Este estudo consiste em utilizar o óxido de zinco (ZnO) como carregador de nanoprata metálica (Ag°). Foi testado um método para síntese das partículas com a prata, o método de Turkevich. A confecção dos filmes poliméricos em matriz de HMSPP/SEBS foi realizada via processamento no estado fundido em extrusora. Os materiais obtidos foram caracterizados pelas técnicas de DLS, MEV e ensaios biocidas. As partículas apresentaram-se em tamanhos variando entre 100 à 200 nm, juntamente a isso, elas também apresentaram resultados de morte celular nos ensaios biocidas com as bactérias E.coli e S.aureus de acordo com a norma JIZ 2801.
Study of stability in gamma irradiation of luminescent film of PMMA with Eu(3+)/AG nanoparticles
2019 - LIMA, VINICIUS da S.; KOMATSU, LUIZ G.H.; LUGAO, ADEMAR B.; PARRA, DUCLERC F.
Lanthanides, which are part of rare earths, have attracted attention due to their optical properties not only in research field, but also, in industrial and technological areas. Eu3+ ions are among the most studied of the rare earth complexes because they present higher luminescence, due to the structures of their energy levels. The combination with ligands of high molar absorptivity can promote a higher emission of the rare earth ions. The luminescent polymer system used as markers was obtained from doping with rare earth complexes, incorporating a Europium complex containing tenoyltrifluoroacetonate (TTA) and triphenylphosphine oxide (TPPO) anion in the process of encapsulating silver nanoparticles in methyl polymethacrylate (PMMA). The luminescent and thermal properties of the material were analyzed in the luminescent films before and after exposure to ionizing radiation in a 60Co source at doses of 10, 30 and 50 kGy. The TTA ligand undergoes decay of the luminescence when the precursor complex is exposed to ionizing radiation. Once doped in the PMMA polymer matrix it will be possible to protect stabilizing the luminescence of the complex. The study of the luminescence properties was performed by the spectrofluorimetry technique. The thermal properties and the decomposition profile of the material were obtained by the Thermogravimetric Analysis (TGA / DTG) in N2 atmosphere. To investigate the enthalpic variations of the samples, the Differential Exploration Calorimetry (DSC) technique was used in N2 atmosphere.
Antibacterial effect of silver incorporated polyethylene blown film for active packaging use
2017 - OLIANI, WASHINGTON L.; PARRA, DUCLERC F.; KOMATSU, LUIZ G.H.; LINCOPAN, NILTON; RANGARI, VIJAYA K.; LUGAO, ADEMAR B.
Food packaging is used to maintain the quality and safety of food products during storage and transportation, and to extend the shelf-life of food products. This is done by preventing unfavourable factors or conditions such as oxygen, light, moisture, spoilage microorganisms, chemical contaminants, mechanical resistance, etc. To be able to do so, packaging materials provide physical protection and also create the proper physicochemical conditions for each product necessary to obtain adequate shelf life and maintain food quality and safety. We report the preparation of polyethylene blown films containing silver nanoparticles by using the ultrasound technique. The silver nitrate was mixed with the surfactant oleic acid (AO) and sonicated for 30 minutes. This solution was mixed with polyethylene using a rotary mixer for 12 hours. Nanocomposites of low density polyethylene (LDPE) with linear low density polyethylene (LLDPE) blends and silver nanoparticles were prepared under melt in a twin screw extruder, using PE-g-MA as compatibilizer agent, ethylene graft maleic anhydride copolymer. The films were characterized by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDX), field emission scanning electron microscopy (FESEM), differential scanning calorimetry (DSC), percentage reduction of colony-forming units (CFU). The bacterial effect of Escherichia coli and Staphylococcus aureus were assessed in detail.
Thermal-oxidation of HMSPP nanocomposites based on montmorillonite clay
2017 - KOMATSU, LUIZ G.H.; OLIANI, WASHINGTON L.; RODELLA, EVERTON F.; PARRA, DUCLERC F.
Nanocomposites based on high melt strength polypropylene (HMSPP) with montmorillonite clay were submitted to thermal assay. The samples were processed utilizing a twin screw extruder. The dumbbell samples were obtained by thermopressing and mounted in stove with air circulation. The effects of thermal assay on the nanocomposite were evaluated by Melt Flow Index (MFI), Energy Dispersive Scanning (EDS) and differential scanning calorimetry (DSC). It was observed that presence of clay can accelerate the process of thermal aging at lower content of 1wt%.
Nanocomposites based on polypropylene with nanosilver particles and antibacterial behavior – a review
2016 - OLIANI, W.L.; PARRA, D.F.; KOMATSU, L.G.H.; LINCOPAN, N.; RANGARI, V.K.; LUGAO, A.B.
This paper presents a study of polypropylene (PP) films modified by gamma irradiation with insertion of silver nanoparticles (AgNPs) and montmorillonite (MMT) aiming bactericide effect. The use of silver (Ag) gives important antibacterial property since silver is highly toxic for bacteria. The PP matrix was processed in a twin screw extruder and polypropylene nanocomposites (PPNC) were obtained in different concentrations of 0.25%; 0.5%; 1.0%; 2.0% and 4.0% in wt% and 1% of MMT. The material was characterized by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), field emission scanning electron microscopy (FESEM), X-ray diffraction spectroscopy (XRD), cytotoxicity assay and reduction colony-forming-unit (CFU). The analyzed films showed spherical clusters and homogeneous regions with good distribution of the silver nanoparticles. Furthermore, the PP@AgNPs films exhibited a strong antibacterial efficiency against S. aureus, E. coli and P. aeruginosa due to the presence of the biocidal silver nanoparticles.
Processing and antimicrobial efficacy of polypropylene/montmorillonite/silver nanocomposites as food packaging films
2016 - OLIANI, WASHINGTON L.; KOMATSU, LUIZ G.H.; LINCOPAN, NILTON; RANGARI, VIJAYA K.; LUGAO, ADEMAR B.; PARRA, DUCLERC F.
The aim this study was to use nanocomposites of polypropylene (PP), montmorillonite (MMT) and silver nanoparticles (AgNPs), prepared by melt intercalation in a twin-screw extruder, as a food packaging bactericide material. The use of nanoclay and nanosilver as additives for polymer matrices requires, in some cases (with non-polar matrices) the use of a compatibilizer agent which will act as a bridge or permanent buffer for nanoclay-nanosilver-matrix interaction. As compatibilizer agent it has been used a propylene graft maleic anhydride copolymer (PP-g-MA). The nanocomposites were evaluated by differential scanning calorimetry (DSC), X-Rays diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and determination of antibacterial activity. The results indicate the formation of microstructures predominantly exfoliated. Further, the antibacterial properties of the films were investigated against Escherichia coli (Gram-negative) and Staphylococcus aureus (Gram-positive) bacteria.
Thermal-oxidation behaviour of modified polypropylene nanocomposites obtained in molten state
2014 - KOMATSU, L.G.H.; OLIANI, W.L.; LUGAO, A.B.; PARRA, D.F.