LUIZ GUSTAVO HIROKI KOMATSU
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Artigo IPEN-doc 28261 Preparation of irradiated silver nanoparticles for polypropylene nanocomposites with pineapple fiber2021 - ZAINE, M.A.; DALLA VECCHIA, M.E.K.; KOMATSU, L.G.H.; OLIANI, W.L.; PARRA, D.F.Capítulo IPEN-doc 27630 Processing and characterization of polyethylene-AgNPs films2020 - 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.Artigo IPEN-doc 23185 Fabrication of polypropylene/silver nanocomposites for biocidal applications2017 - 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.Artigo IPEN-doc 23614 Nanocomposites based on polypropylene with nanosilver particles and antibacterial behavior – a review2016 - 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.Resumo IPEN-doc 23613 Análise da degradação dos nanocompósitos de polipropileno modificado sob condições de envelhecimento acelerado em estufa e natural2016 - KOMATSU, L.G.H.; OLIANI, W.L.; LUGAO, A.B.; PARRA, D.F.O entendimento dos mecanismos de degradação que agem sob os nanocompósitos polimericos frente ao intemperismo (luz UV, calor, chuva ácida e entre outros), é o ponto chave para o desenvolvimento de novos aditivos. Para esta análise, as amostras de nanocompósitos de polipropileno modificado por radiação gamma foram obtidos por meio de processamento em extrusora de dupla rosca. Posteriormente estas amostras foram submetidas a ensaios de envelhecimento acelerado em estufa e envelhecimento natural. Os efeitos dos ensaios de envelhecimento foram avaliados por meio das técnicas de, Calorimetria Exploratória Diferencial (DSC), Espectroscopia de Infravermelho pela Transformada de Fourier (FT-IR), Índice Carbonila (IC), Índice de Fluidez (IF), Espectroscopia de Energia Dispersiva (EDS) e Microscopia Eletrônica de Varredura (MEV). Com o decorrer do ensaio de envelhecimento foi possível realizar uma correlação entre o índice de carbonila e índice de fluidez durante o processo degradativo.Artigo IPEN-doc 22812 Processing and antimicrobial efficacy of polypropylene/montmorillonite/silver nanocomposites as food packaging films2016 - 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.Artigo IPEN-doc 22323 Thermal-oxidation behaviour of modified polypropylene nanocomposites obtained in molten state2014 - KOMATSU, L.G.H.; OLIANI, W.L.; LUGAO, A.B.; PARRA, D.F.Artigo IPEN-doc 22156 Nanocomposites of irradiated polypropylene with clay are degradable ?2016 - KOMATSU, L.G.H.; OLIANI, W.L.; LUGAO, A.B.; PARRA, D.F.Artigo IPEN-doc 22128 Fabrication of gamma-irradiated polypropylene and AgNPs nanocomposite films and their antimicrobial activity2016 - BERENGUER, ISABELLE O.; OLIANI, WASHINGTON L.; PARRA, DUCLERC F.; KOMATSU, LUIZ G.H.; SANTOS, VINICIUS J.; LINCOPAN, NILTON; LUGAO, ADEMAR B.; RANGARI, VIJAYA K.Artigo IPEN-doc 22012 Degradation study of High Melt Sterngt Polypropylene/Clay nanocomposites in environmental and accelerated conditions2016 - KOMATSU, LUIZ G.H.; PARRA, DUCLERC F.; OLIANI, WASHINGTON L.; LUGAO, ADEMAR B.; RANGARI, VIJAYA K.