Papers by Carlos Toshiyuki Hiranobe
Clean technologies, Jun 3, 2024
This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
Journal of materials research and technology/Journal of Materials Research and Technology, May 1, 2024
Polymers, Feb 8, 2024
This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
Materials Research-ibero-american Journal of Materials, Dec 31, 2022
In juice and pulp extraction, about 10% of fruit waste is generated, which often ends up in landf... more In juice and pulp extraction, about 10% of fruit waste is generated, which often ends up in landfills that can cause environmental damage, serve as food for insects and rodents, and cause health problems for humans. In this work, micronized guava waste was used as a filler in vulcanized compounds in natural rubber. Mechanical properties such as hardness, tensile strength, tear resistance, and abrasion resistance were evaluated, as well as thermal properties such as thermogravimetric analysis, in addition to scanning electron microscopy, X-ray fluorescence, elemental analysis, and infrared spectroscopy. According to the results of the mechanical properties tests, the addition of up to 20 phr of the filler tends to improve the tensile strength of the composites, resulting in an increase in the density of crosslinks obtained through the Flory-Rehner method. The thermal behavior analyzed by TGA and FTIR spectra were not affected by the incorporation of fillers.
Polymers
Nowadays, biocomposites represent a new generation of materials that are environmentally friendly... more Nowadays, biocomposites represent a new generation of materials that are environmentally friendly, cost-effective, low-density, and not derived from petroleum. They have been widely used to protect the environment and generate new alternatives in the polymer industry. In this study, we incorporated untreated jute fibers (UJFs) and alkaline-treated jute fibers (TJFs) at 1–5 and 10 phr into TSR 10 natural rubber as reinforcement fillers. These composites were produced to be used in countersole shoes manufacturing. Untreated fibers were compared to those treated with 10% sodium hydroxide. The alkali treatment allowed the incorporation of fibers without compromising their mechanical properties. The TJF samples exhibited 8% less hardness, 70% more tensile strength, and the same flexibility compared to their pure rubber counterparts. Thanks to their properties and ergonomic appearance, the composites obtained here can be useful in many applications: construction materials (sound insulatin...
Engineering & Technology Scientific Journal
A preocupação com a atual matriz energética do mundo provocou muitos países a buscarem formas mai... more A preocupação com a atual matriz energética do mundo provocou muitos países a buscarem formas mais sustentáveis de produzir energia, uma dessas forma é através da utilização da biomassa proveniente de resíduos urbanos e agrícolas. Através da briquetagem, há uma maneira de transformar os resíduos, que não seriam reutilizados nem descartados de forma correta, em briquetes que é um biocombustível sólido e compactado. Nesta pesquisa, os briquetes foram feitos em laboratório utilizando misturas de Pinus sp. e bagaço de cana de açúcar. Com um total de sete tratamentos, T1(100% Bagaço), T2(25% Pinus + 75% Bagaço), T3(75% Pinus + 25% Bagaço), T4(100% Pinus), enquanto que "T5", "T6" e "T7" foram feitos com uma proporção de 50% Pinus e 50% Bagaço, todos os tratamentos têm uma granulometria de 10 mesh. O objetivo do presente projeto foi analisar a resistência mecânica das misturas. Os briquetes foram produzidos com uma máquina de briquetagem manual com uma pressão...
Engineering & Technology Scientific Journal
O aproveitamento de resíduos agroindustriais é uma solução para um grande problema da humanidade ... more O aproveitamento de resíduos agroindustriais é uma solução para um grande problema da humanidade que é o descarte de resíduos. A densificação energética é uma forma muito eficiente de mitigar esse problema, pois ela transforma um resíduo de descarte em energia útil. Resíduos como os têxtis e os agroflorestais possuem em sua grande maioria um poder calorífico interessante. Neste estudo foi realizada a confecção de briquetes utilizando misturas de resíduo têxtil e de cepa de mandioca.Quanto aos parâmetros de qualidade, no teste de durabilidade todas as blendas obtiveram resultados satisfatórios obtendo valores de durabilidade superiores a 97%, porém em resistência ao impacto o briquete feito de 100% têxtil obteve o pior resultado o que indica que ele não tem uma resistência a quedas desejável, já as outras blendas foram excelentes neste teste também, com destaque a blenda de 25% têxtil e 75% cepa que obteve o melhor desempenho. Dessa forma, pode se afirmar que as misturas de material ...
Engineering & Technology Scientific Journal
A definição de biochar é dada como sendo um resíduo biológico produzido a partir de uma pirólise ... more A definição de biochar é dada como sendo um resíduo biológico produzido a partir de uma pirólise com baixos níveis de oxigênio, o que resulta num material poroso e com baixa densidade de carbono (Beesley et al., 2011). Considerando que o Biochar é um biocarvão, composto por resíduos orgânicos (palha de cana-de-açúcar, mandiocas, e entre outros) e residuos animais sendo formado através da pirólise lenta (temperatura inferior a 500°) com baixos níveis e sem controle no oxigênio. A pesquisa em questão traz um reaproveitamento no agro com o intuito de reutilização dos resíduos como casca de mandioca para formação de biochar. Com este aspecto foi desenvolvida a pesquisa em torno de bibliografias e documentos, trazendo uma contextualização para o aprofundamento no assunto e iniciando as discussões como as análises da pirólise, análise química imediata, densidade a granel. O PCS do material in natural foi de 11,35 MJ/Kg. Com a pirólise a uma temperatura de 450°C, com tempos diferentes co...
Polymers
Nowadays, biocomposites represent a new generation of materials that are environmentally friendly... more Nowadays, biocomposites represent a new generation of materials that are environmentally friendly, cost-effective, low-density, and not derived from petroleum. They have been widely used to protect the environment and generate new alternatives in the polymer industry. In this study, we incorporated untreated jute fibers (UJFs) and alkaline-treated jute fibers (TJFs) at 1–5 and 10 phr into TSR 10 natural rubber as reinforcement fillers. These composites were produced to be used in countersole shoes manufacturing. Untreated fibers were compared to those treated with 10% sodium hydroxide. The alkali treatment allowed the incorporation of fibers without compromising their mechanical properties. The TJF samples exhibited 8% less hardness, 70% more tensile strength, and the same flexibility compared to their pure rubber counterparts. Thanks to their properties and ergonomic appearance, the composites obtained here can be useful in many applications: construction materials (sound insulatin...
Research Square (Research Square), Feb 23, 2021
The present research aimed to develop natural rubber (NR) hybrid composites reinforced with treat... more The present research aimed to develop natural rubber (NR) hybrid composites reinforced with treated ultra ne calcium carbonate/carbon black (CC/CB). The in uence of CC/CB with various ller ratios (50/0, 40/10, 30/20, 20/30, 10/40 and 0/50) on mechanical properties and cure characteristics of the vulcanizates was investigated and their reinforcing e ciency was compared aiming to achieve the best ratio for CB partial substitution as compared to composites with CC and CB incorporated separately. The CC 30 /CB 20 composites reached around to 17 MPa similar strength at break response compared to CC 0 /CB 50 (16.83 MPa). Elongation at break increased 48% in relation to CC 0 /CB 50. Hardness maintain similar values compare to high concentration of CB composites. Crosslink density results revealed similar chain number in rubber matrix representing better interaction between CC/CB. Scanning electron microscopy studies also reveal a good ller dispersion between ller particles and matrix. The results shown that the new material can be an alternative ller for partial substitution of CB conserving mechanical properties.
Journal of Material Cycles and Waste Management
Materials Research
The biodiversity of plant resources is a renewable source that can use as a sustainable component... more The biodiversity of plant resources is a renewable source that can use as a sustainable component in various applications. The use of vegetable waste as a filler element in polymeric composites is part of the solid waste management policy and the sustainable development of agribusiness. In this work, the natural rubber composites were prepared with acai seed in proportions of 0, 10, 20, 30, 40, and 50 phr (per hundred rubber). The composites were homogenized in an open cylinder mixer and characterized by rheometric, morphological, mechanical, and thermal tests. The addition of the organic fillers significantly reduced the vulcanization process time. Thermogravimetric analysis and infrared spectroscopy showed that the composites were thermally stable and showed no structure changes after the vulcanization process, respectively. The Lorenz-Parks method's evaluation of matrix/filler interactions showed a strong interaction between NR/Acai. The new biocomposite can replace nonecological composites economically and sustainably.
Science of The Total Environment
In this study, we determined the Cr(VI) in samples of tanned leather residues by differential pul... more In this study, we determined the Cr(VI) in samples of tanned leather residues by differential pulse voltammetry (DPV) using graphite/paraffin composite electrodes modified with reduced graphene oxide nanosheets (referred to as GPEs/nsRGO). After the modification, the composite electrodes were characterized by two electrochemical techniques (i.e., cyclic voltammetry, CV, and electrochemical impedance spectroscopy, EIS), scanning electron microscopy, and Raman spectroscopy. The electroanalytical method was applied using the GPEs/nsRGO. An analytical curve was obtained in a Clark-Lubs buffer solution (pH = 1), with a linear concentration range from 25.0 to 392.0 μmol L-1 and a limit of detection (LOD) of 1.01 μmol L-1. The GPEs/nsRGO showed good reproducibility in their manufacturing process and good response repeatability with an RSD of 4.59% over twelve measurements. These composite electrodes showed excellent selectivity, which was demonstrated by analyses in the presence of metal ions (Ca2+, Zn2+, Mg2+, Fe3+, Co2+, Na+, and Cu2+) that did not interfere in the analysis of Cr(VI). The GPEs/nsRGO were applied to the determination of Cr(VI) in real samples of wet-blue leather and leather ash using DPV. This approach was validated using the sample recovery method, where it presented values from 95.6 to 108.2%. The proposed method showed satisfactory results compared to the literature and can be considered a good alternative for the determination of Cr(VI) in aqueous samples.
Journal of Applied Polymer Science
Universidade Estadual Paulista (UNESP), Jan 31, 2020
Crystals
In this work investigated the possibility of applying a superficial treatment to ultra-fine calci... more In this work investigated the possibility of applying a superficial treatment to ultra-fine calcium carbonate aiming to improve its interaction with the polymer chains of natural rubber so it does not act just as a filler. Commercial processes commonly use 40 phr of Silica as reinforcement filler. Here, we have evaluated the partial replacement of Silica by two types of calcium carbonate into hybrid natural rubber composites, untreated ultra-fine calcium carbonate and with ultra-fine calcium carbonate treated with 2% Chartwell C-515.71HR®. We added calcium carbonate fillers to the composite mixtures (as replacements for commercial silica treated with silane) and studied their influence on the vulcanization process. According to our findings, between 25% and 75% of the silica can be replaced with treated calcium carbonate, and up to 30 parts of CaCO3 can be combined with 100 parts of NR without compromising the properties of the polymer matrix (NR), which generates economic advantage...
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Papers by Carlos Toshiyuki Hiranobe