LUIZ GUSTAVO HIROKI KOMATSU

LUIZ GUSTAVO HIROKI KOMATSU

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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.
Synthesis of TiO2-doped- Ag for biocide activity on SEBS/PP applications
2020 - KOMATSU, L.G.; OLIANI, W.L.; LUGAO, A.B.; PARRA, D.F.
Antimicrobial activity represents a challenge for scientific community. Polymer processing conditions impose temperature limitation for stability of biocide nanoparticles. In the present work, we evaluate TiO2-doped-Ag synthesized in laboratory, utilizing P25 Degussa Titanium Dioxide as precursor. The main proposal is to improve the incorporation of Ag on TiO2. The nanoparticles was tested by reduction of colony units formation (CFU)(%), Dynamical Light Scattering (DLS) and Zeta potential values. On CFU tests, all samples showed biocide properties. The samples showed biocide effect on E.coli and S.aureus bacteriae. The same nanoparticle was tested after sterilization under gamma irradiation, and showed an increase on biocide effect against S.aureus bacteria. The obtained biocide material was processed in SEBS/PP to obtain biocide polymeric films. The new material was characterized by: forming colony units (CFU)(%), Differential Scanning Calorimetry (DSC), and Fourier Transformed Infrared (FT-IR).
Processing and characterization of polyethylene-AgNPs films
2020 - OLIANI, WASHINGTON L.; KOMATSU, LUIZ G.H.; LUGAO, ADEMAR B.; RANGARI, VIJAYA K.; PARRA, DUCLERC F.
Low-density-polyethylene (LDPE) and Linear-low-density-polyethylene (LLDPE) nanocomposites films containing silver nitrate (AgNO3) and surfactant oleic acid (AO) were manufactured via extrusion and subsequently characterised. The films were evaluated by scanning electronmicroscopy (SEM), energy dispersive spectroscopy (EDX), differential scanning calorimetry (DSC), transmission electron microscopy (TEM), and infrared spectroscopy (FTIR). Further, the antibacterial properties of the films were investigated against Escherichia coli (Gram-negative) and Staphylococcus aureus (Gram-positive) bacteria.The results indicated that LDPE nanocomposite films containing AgNPs have the potential to be used in antimicrobial packaging for food applications.
Nanopartículas de Ag/TiO2 e Ag/CaCO3 aplicados em matrizes polímericas de HMSPP/SEBS visando atividade biocida
2018 - KOMATSU, L.G.H.; OLIANI, W.L.; RODELLA, E.F.; LUGAO, A.B.; PARRA, D.F.
As propriedades e a atividade biocida do compósito nanoestruturado de Polipropileno com Alta Resistência do Fundido (iPP) com o Elastômero Termoplástico estirenoetileno/ butadieno-estireno (SEBS), utilizando as nanopartículas de prata com dióxido de titânio (Ag/TiO2) e nanopartículas de prata com carbonato de cálcio (Ag/CaCo3) foram avaliadas por Espalhamento de Luz Dinâmico (DLS), Difração de Raios-X (DRX), Calorimetria Diferencial Expolratória (DSC), Espectroscopia de Raman, e ensaios biocidas. As nanopartículas de Ag/TiO2 e Ag/CaCO3 foram sintetizadas em laboratório, tendo como precursor metálico o nitrato de prata (AgNO3). Tanto os corpos de prova para os testes quanto o processamento dos compósitos, foram realizados em uma máquina inejetora de bancada. Investigou-se a formação de halo de inibição em ambos os materiais PP/SEBS/Ag/ TiO2 e PP/SEBS/Ag/CaCO3 frente a bactéria E. coli, afim de avaliar a dispersão e o tamanho da partícula que promova uma melhor interação com as celúlas das bactérias.
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.
Synthesis of ZnO for biocide activity on SEBS/PP applications
2017 - KOMATSU, LUIZ G.H.; OLIANI, WASHINGTON L.; RANGARI, VIJAYA K.; PARRA, DUCLERC F.; LUGAO, ADEMAR B.
Antimicrobial activity represents a challenge for scientific community. Polymer processing conditions impose temperature limitation for stability of biocide nanoparticles. In the present work, we evaluate ZnO synthesized in laboratory, utilizing Zn(NO3)26H2O as precursor. The main proposal is to improve the incorporation of this nanoparticle on SEBS/PP resulting on biocide material films. Before application on SEBS/PP, the nanoparticles was tested by reduction of forming colony units (CFU)(%), Dynamical Light Scattering (DLS) and Zeta potential. On CFU tests, all samples showed biocide properties. The samples with concentration of 1% showed the higher biocide effect on E.coli bacteria, in comparison of lower concentrations. The obtained material biocide was processed on SEBS/PP for obtaining of polymeric films with biocide activity and the new material was characterized by: forming colony units (CFU)(%), Differential Scanning Calorimetry (DSC), and Fourier Transformed Infrared (FTIR).
Preparation and characterization of polyethylene nanocomposites with clay and silver nanoparticles
2017 - OLIANI, WASHINGTON L.; FERMINO, DANILO M.; KOMATSU, LUIZ G.H.; LUGAO, ADEMAR B.; RANGARI, VIJAYA K.; LINCOPAN, NILTON; PARRA, DUCLERC F.
Polyethylene is widely used for packing applications. Different grades of polyethylene, LLDPE and LDPE play a major role in the film blowing industry. The use of nanoclay in polymer matrices (non-polar) requires the use of a compatibilizer agent, ethylene graft maleic anhydride copolymer (PE-g-MA), which acts as a bridge for nanoclay-matrix-interaction. In our study, blown films of LLDPE, LDPE, and their blends were produced using a twin screw extruder. The combination of PEs as matrix, montmorillonite (MMT) and silver nanoparticles (AgNPs) intended to improve mechanical and thermal properties. Nanocomposites films with 1 wt% of montmorillonite and 0.5–1.0 wt% silver nanoparticles were prepared by blow extrusion and evaluated. Nanoclay intercalation/exfoliation degree was investigated by X-ray diffraction spectroscopy (XRD) and scanning electron microscopy (SEM). Mechanical and thermal properties were evaluated. The results showed optimum dispersion at intercalation/exfoliation levels for polyethylene nanocomposite (PENC), slight increasing in mechanical and especially improvement in thermal properties.
Fabrication of polypropylene/silver nanocomposites for biocidal applications
2017 - OLIANI, WASHINGTON L.; PARRA, DUCLERC F.; KOMATSU, LUIZ G.H.; LINCOPAN, NILTON; RANGARI, VIJAYA K.; LUGAO, ADEMAR B.
This paper presents a study on biocidal effect of polymer nanocomposite films of gamma irradiated polypropylene (PP) and silver nanoparticles. The modified polypropylene was obtained from isotactic polypropylene (iPP) in pellets form by irradiation with gamma rays in the presence of acetylene. A new morphology with long chain branching of PP and distinct rheology is obtained by this process. The blend of 50/50 wt neat PP and PP modified by gamma radiation were further mixed using a twin screw extruder. The AgNPs were infused into this polymer blend at different concentrations of: 0.1%; 0.25%; 05%; 1.0%; 1.0% (PVP), 2.0% and 4.0% by wt%. These polymer nanocomposites were characterized by Raman spectroscopy, scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), thermogravimetric analysis (TG), differential scanning calorimetry (DSC), X-ray diffraction (XRD), transmission electron microscopy (TEM), cytotoxicity test and Kirby-Bauer disk diffusion techniques. The bactericidal effect of Pseudomonas aeruginosa (P. aeruginosa) and Staphylococcus aureus (S. aureus) were assessed in detail.
Nanogels of the polypropylene modified by gamma irradiation and incorporation of AgNPs biocide
2016 - OLIANI, WASHINGTON L.; KOMATSU, LUIZ G.H.; LUGAO, ADEMAR B.; PARRA, DUCLERC F.
The objective of this work is to study the formation of nanogel and microgel in modified polypropylene (PP) and incorporation of silver nanoparticles. The PP in pellets was modified by gamma irradiation of pristine PP under a crosslinking atmosphere of acetylene in doses of 5, 12.5 and 20 kGy, followed by thermal treatment for radical recombination and annihilation of the remaining radicals. Thin film of polypropylene gel was obtained by extraction in boiling xylene for period of 12 hours at 138 °C, followed by decantation in beaker at room temperature of 25°C with the total volatilization of the xylene. Deposition of dried material on fine glass blades under agitation by settling process formed films containing nanosilver. The thin films of gel AgNPs formed of pristine PP, as well as, modified (i.e., irradiated) were characterized using Scanning Electron Microscopy (SEM), Energy Dispersive Spectroscopy (EDX), Atomic Force Microscopy (AFM), X-Ray diffraction (DRX), Differential Scanning Calorimetry (DSC) other than determination of antibacterial activity. The PP morphology indicated the nanogels and microgel formation with increase of spherulites concentration and crystallinity at dose 12.5 kGy. Further, the antibacterial properties of the gel-AgNPs polypropylene were investigated against Escherichia coli (Gram-negative) and Staphylococcus aureus (Gram-positive) bacteria.