LUIZ GUSTAVO HIROKI KOMATSU

LUIZ GUSTAVO HIROKI KOMATSU

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Film of the blend of HMSPP/SEBS with TiO2@Ag for biocide activity against Candida albicans and Aspergillus niger for medical applications
2022 - KOMATSU, LUIZ G.H.; COSTA, FERNANDA A.T. da; FERREIRA, BARBARA V.; CAJADO, GIUSEPPE M.; LUGAO, ADEMAR B.; PARRA, DUCLERC F.
One of the most promising ways to overcome the biocide infections on medical materials is the use of metal oxides. The nanoparticle of Titanium Dioxide doped with Silver (TiO2@Ag) is one of the most promising materials due to the biocide properties against the Candida albicansand Aspergillus niger. With these observations, in the present work, the nanoparticles of TiO2@Ag were synthesized by adapting the method of Turkevich [1] and in the sequence, they were incorporated in the polymeric blend of High Melt Strength Polypropylene (HMSPP)[1]/Styrene-Ethylene/Butadiene-Styrene (SEBS). Following that incorporation, it was obtained thin films of 0,3 and 1 %wt concentrations (based in previous results[1]) for characterization tests. The films were evaluated by Biocide tests following the JIS 2801-10 norm with Candidaalbicans ATCC 10231 and Aspergillus niger ATCC 6275, X-ray Diffraction (DRX), Raman Spectroscopy. On biocide tests were observed biocide activity of the film with 0,3wt% of TiO2@Ag showed, in the logarithmic reduction of the bacteria, count upward the standard normalized by the norm (≥2), value of 3,24 of logarithmic reduction. In the Raman Spectroscopy and DRX were confirmed the presence of the Ag on the TiO2: DRX the peak of θ = 23,81 ° was attributed to TiO2@Ag on the film and on Raman Spectroscopy the peak of 1048 cm-1refered to the NO3 -residual of the the silver nitrate, other peaks at 1334 and 1459 cm-1of the silver indicating the presence in the film [2].
Ionizing radiation compatibilization in bio-based blends from PBAT/PLA reinforced with bio-eggshell
2020 - CARDOSO, E.C.; PARRA, D.F.; SCAGLIUSI, S.R.; KOMATSU, L.G.; LUGAO, A.B.
Plastics global annual production exceeds 300 million tons and 99% is originated from oil or fossil combustibles. The amount of plastics wastes utilized exceeds the amount into landfills, prejudicing effectively the environment. As an alternative, they are being slowly replaced by bioplastics, as PLA (poly-lactic acid) and PBAT (butylene adipate co-terephthalate). Food and dairy industries produce annually huge amounts of avian eggshells residues and their disposition presents a serious environmental risk. Bio-load from avian eggshells as polymers reinforcement is based in their higher benefits as resistance and rigidity besides being a friendly environmental material, degradable and renewable. PLA and PBAT are thermoplastics capable to be processed by conventional methods: nevertheless, due to their high interfacial tension, it is required the use of compatibilizers. In this work, additives and heat generally used as compatibilizers were replaced by e-beam radiation, at 150 kGy dose. PBAT/PLA blends were prepared at the weight ratio of 82 / 18 and 5.0 phr of PLA 150 kGy e-beam radiated, at 2.5, 5.0 and 10.0 phr of bio-eggshells. Samples were homogeneized in a co-rotating twin-screw extruder and further characterized for: DSC, TGA, FTIR, XRD and Mechanical essays.
Biocide effects of f nanoparticles of ZnO and ZnO-doped-Ag application in polymeric blend of HMSPP/SEBS
2020 - PARRA, D.F.; BASSETTI, C.; KOMATSU, L.G.
In this study, the nanoparticles of Zinc oxide (ZnO) and Zinc oxide doped with Silver (ZnO/Ag) were synthesized in laboratory. The incorporation of these nanoparticles in the blend of High Melt Strength Polypropylene (HMSPP) and Styrene-Ethylene/Butadiene-Styrene (SEBS) was carried by melting process. The obtained materials were evaluated by X-ray diffraction (XRD), Raman Spectroscopy, Differential Scanning Calorimetry (DSC), biocidal tests against the bacteria E.coli and S.aureus following the JIZ 2801 standard. The nanoparticles sized between 100-200nm have spherical form. HMSPP / SEBS / films incorporated with the nanoparticles AgNPs / ZnO showed biocidal effect against the bacteria E.coli and S.aureus.
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).
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).
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.
Photo-oxidation of modified Polypropylene nanocomposite
2016 - KOMATSU, LUIZ G.H.; OLIANI, WASHINGTON L.; LUGAO, ADEMAR B.; PARRA, DUCLERC F.
All polymers when exposed to the environment suffer diverses alterations due to the action of diverse factors such UV light, poluition, acid rain and others. In this study, the modified polypropylene by gamma irradiation (HMSPP – high melt strength polypropylene) was blended with Cloisite 20A to obtain HMSPP nanocomposite. The PP-g-MA, polypropylene graft maleic anhydride, was utilized as compatibilizant agent [1]. The samples were processed in twin-screw extruder and the dumbbell samples were obtained by thermopressing. The samples was exposed in environment by 6 months [1,2]. The chemical analysis was evaluate by Carbonyl Index (CI) and Melt Flow Index (MFI). With increase of time, the CI also increased, indicating the chain scission process, principally in the chain backbone, as observed in MFI, which value has increased very fast with increasing of time.
Irradiation influence on the properties of HMS-polypropylene CLAY/AGNPS compound masterbatches
2016 - OLIANI, W.L.; PARRA, D.F.; KOMATSU, L.G.H.; RANGARI, V.K.; LINCOPAN, N.; LUGAO, A.B.
High melt strength polypropylene (HMSPP) nanocomposite under photo and thermal ageing
2016 - KOMATSU, L.G.H.; PARRA, D.F.; OLIANI, W.L.; LUGAO, A.B.
Microscopy, a vital technique for the study of microgels and nanogels polypropylene modified by gamma irradiation
2011 - OLIANI, W.; PARRA, D.F.; KOMATSU, L.G.; RIELLA, H.G.; LIMA, L.F.C.P.; LUGAO, A.B.