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24 results on '"Hiranobe, Carlos Toshiyuki"'

1. Sustainable construction materials for low-cost housing: Thermal insulation potential of expanded SBR composites with leather waste

Author

Ribeiro, Gabriel Deltrejo, Hiranobe, Carlos Toshiyuki, Araújo, Samara da Silva, Filgueira, Matheus da Silva, Rocha, José Afonso, Mukuno, Jefferson Shiguemi, Salmazo, Leandra Oliveira, Gomes, Andressa Silva, Tolosa, Gabrieli Roefero, Gennaro, Elmer Mateus, Job, Aldo Eloizo, Pérez, Miguel Angel Rodríguez, and Santos, Renivaldo José dos

Published
2024
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4. Kinetics of Supercritical CO 2 Extraction from Burrito (Aloysia polystachya) Leaves and Sucupira-Preta (Bowdichia virgilioides) Seeds.

Author

Vieira, Gabrielle Vaz, Souza, Michel Rubens dos Reis, Hiranobe, Carlos Toshiyuki, Goncalves, José Eduardo, Moritz, Cristiane Mengue Feniman, Sakai, Otávio Akira, e Silva, Leila Maria Sotocorno, da Silva, Michael Jones, da Silva, Erivaldo Antônio, dos Santos, Renivaldo José, da Silva, Edson Antônio, Cardozo-Filho, Lucio, and Ferreira-Pinto, Leandro

Subjects
VITAMIN E, EXTRACTION techniques, FACTORIAL experiment designs, CHOICE (Psychology), VEGETABLE oils
Abstract

This study investigated the application of supercritical carbon dioxide (CO2) for the extraction of essential oils from plant materials with anxiolytic potential, focusing on the leaves of burrito (Aloysia polystachya) and the seeds of sucupira-preta (Bowdichia virgilioides). The supercritical extraction technique was chosen for its ability to produce high-purity extracts without residual solvents and to reduce the environmental impact. This study evaluated the influence of temperature (40 °C, 50 °C, and 60 °C) and pressure (22 MPa, 25 MPa, and 28 MPa) on extraction efficiency using a 22 factorial design with triplicates at the central point. The maximum yields were 1.2% for burrito leaves and 4.2% for sucupira-preta seeds. Despite their relatively low yields, the extracts contained a diverse range of chemical compounds, including fatty acids (oleic, linoleic, and palmitic acids), squalene, β-carotene, vitamin E, and other bioactive molecules with antioxidant, anti-inflammatory, and immunomodulatory properties. Statistical analysis demonstrated that pressure was the most influential factor affecting yield, whereas temperature played a secondary role. The Sovová kinetic model provided a good fit for the extraction curves, with determination coefficients (R2) above 0.95, thus validating the efficiency of the method. These results highlight the pharmaceutical potential of these extracts, particularly for therapeutic and anxiolytic purposes. [ABSTRACT FROM AUTHOR]

Published
2025
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5. Evaluation of the Antioxidant Properties of Black Acacia (Acacia mearnsii) Tannin in Vulcanized Natural Rubber Using Different Vulcanization Systems.

Author

Filgueira, Matheus da Silva, Pinto, Leandro Ferreira, Hiranobe, Carlos Toshiyuki, de Freitas, Amanda de Sousa Martinez, Rodrigues, Jéssica de Souza, de Oliveira, André Luis, Ferreira, Marystela, Kawall, Samara Araújo, Souza, Dener da Silva, da Silva, Erivaldo Antonio, Nascimento, Eduardo Soares, Silva, Michael Jones da, Cabrera, Flávio Camargo, Gennaro, Elmer Mateus, and dos Santos, Renivaldo José

Abstract

Given the growing interest of the rubber industry in seeking alternatives that contribute to environmental sustainability, this work aims to present a study of the mechanical, thermal, and structural properties of natural rubber composites using tannin extracted from Acacia mearnsii as an antioxidant agent. Tannin is a natural and biodegradable product, rich in polyphenols and known for its antioxidant properties. The analyses assessed the effectiveness of incorporating tannins (0, 1, 1.5, and 2 parts per hundred rubber) into sulfur-crosslinked natural rubber composites using a binary accelerator system across three distinct vulcanization schemes: conventional, semi-efficient, and efficient. Initially, tannin characterization tests were conducted, revealing characteristic polyphenol bands of proanthocyanidin catechins, a high total phenolic content, and a substantial reduction in antioxidant activity. These findings highlight the significant antioxidant potential of tannins, particularly for industrial and biological applications. The analyses of the characteristics of natural rubber composites with tannin incorporation indicated that the type of vulcanization process directly affects the antioxidant action of the plant tannin, with the tannins being most effective in the efficient system due to the formation of monosulfidic and disulfidic bonds. Furthermore, the incorporation of tannin did not compromise the physical and chemical properties of the materials, highlighting it as a viable additive for the rubber industry. [ABSTRACT FROM AUTHOR]

Published
2024
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6. DETERMINAÇÃO DA DENSIDADE DE LIGAÇÕES CRUZADAS EM BORRACHA NATURAL PARA DIFERENTES SISTEMAS DE VULCANIZAÇÃO

Author

Carvalho, Arthur Pimentel de, primary, Santos, Harison França do, additional, Hiranobe, Carlos Toshiyuki, additional, Budemberg, Eduardo Roque, additional, Ribeiro, Gabriel Deltrejo, additional, Torres, Giovanni Barrera, additional, Resende, Jose Francisco, additional, Paim, Leonardo Lataro, additional, Salmazo, Leandra Oliveira, additional, Pérez, Miguel Ángel Rodríguez, additional, and Santos, Renivaldo José dos, additional

Published
2022
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7. DETERMINAÇÃO DA DENSIDADE DE LIGAÇÕES CRUZADAS EM BORRACHA DE ESTIRENO-BUTADIENO (SBR) PARA DIFERENTES SISTEMAS DE VULCANIZAÇÃO

Author

Santos, Harison Franca do, primary, Carvalho, Arthur Pimentel de, additional, Hiranobe, Carlos Toshiyuki, additional, Budemberg, Eduardo Roque, additional, Ribeiro, Gabriel Deltrejo, additional, Torres, Giovanni Barrera, additional, Resende, Jose Francisco, additional, Paim, Leonardo Lataro, additional, Salmazo, Leandra Oliveira, additional, Pérez, Miguel Ángel Rodríguez, additional, and Santos, Renivaldo José dos, additional

Published
2022
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8. Artificial neural network modeling for predicting the carbon black content derived from unserviceable tires for elastomeric composite production.

Author

Cruz, Marco Antônio Galindo, Hiranobe, Carlos Toshiyuki, Cardim, Guilherme Pina, Cabrera, Flávio Camargo, Ribeiro, Gabriel Deltrejo, Tolosa, Gabrieli Roefero, Garcia, Rogério Eduardo, and dos Santos, Renivaldo José

Subjects
ARTIFICIAL neural networks, CARBON-black, WASTE tires, VULCANIZATION, CARBON emissions, RUBBER
Abstract

Given the increasing need for sustainable solutions and the large amount of improperly discarded end‐of‐life tires, recovered carbon black (rCB) from tire pyrolysis was investigated as a filler for rubber composites. This study considered rCB as an alternative to commercial carbon black due to its sustainability and CO2 emissions reduction. Composites with varying rCB contents (0 to 50 per 100 rubber) were produced and assessed for mechanical properties, such as hardness, abrasion resistance, and rheometric tests. The findings were used to train artificial neural networks (ANNs) with MATLAB software to predict rCB contents. Input parameters included optimal curing time, minimum and maximum torque, and results of mechanical tests like Shore A hardness and abrasion loss. The model was trained on data from 90 samples, with 10 reserved for validation. The predicted outcomes closely matched the experimental data, with a maximum prediction error of less than 3%. This indicates that ANNs are effective tools for intelligently modeling the curing process of natural rubber mixtures, minimizing material waste, optimizing production time, and determining suitable carbon black contents for desired mechanical properties. [ABSTRACT FROM AUTHOR]

Published
2024
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9. Analyzing the Reinforcement of Multiwalled Carbon Nanotubes in Vulcanized Natural Rubber Nanocomposites Using the Lorenz–Park Method.

Author

Melo, Diego Silva, Hiranobe, Carlos Toshiyuki, Tolosa, Gabrieli Roefero, Malmonge, José Antônio, Cena, Cicero Rafael, Job, Aldo Eloizo, Santos, Renivaldo José, and Silva, Michael Jones

Subjects
MULTIWALLED carbon nanotubes, DYNAMIC mechanical analysis, GLASS transition temperature, ELECTROMAGNETIC shielding, ABRASION resistance
Abstract

In this study, multiwalled carbon nanotubes (MWCNTs) were incorporated into vulcanized natural rubber (VNR) matrixes to create nanocomposites with improved mechanical, thermal, and electrical properties. The interfacial interaction of the MWCNTs with the VNR matrix was quantitatively evaluated based on the crosslink density value calculated using the Flory–Rehner methodology. Various rheometric parameters were influenced by the addition of the MWCNTs, including minimum torque (ML), maximum torque (MH), and scorch time (tS1). The MWCNTs significantly enhanced the vulcanization of the composites based on the VNR matrix. This study highlights the impact of MWCNTs on crosslink density, improving mechanical properties and reducing swelling in the VNR matrix. We discovered that the MWCNTs and the VNR matrix interact strongly, which improved the mechanical properties of the matrix. The MWCNTs improved the hardness, tensile strength, and abrasion resistance of the VNR/MWCNT nanocomposites. Based on dynamic mechanical analysis, MWCNT incorporation improved stiffness as indicated by a change in storage modulus and glass transition temperatures. The addition of MWCNTs to the VNR/MWCNT nanocomposites significantly improved their electrical properties, reaching a percolation threshold where conductive pathways were formed, enhancing their overall conductivity. Overall, this study demonstrates the versatility and functionality of VNR/MWCNT nanocomposites for a variety of applications, including sensors, electromagnetic shielding, and antistatic blankets. [ABSTRACT FROM AUTHOR]

Published
2024
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10. Sustainable Composites: Analysis of Filler–Rubber Interaction in Natural Rubber–Styrene–Butadiene Rubber/Polyurethane Composites Using the Lorenz–Park Method and Scanning Electron Microscopy

Author

De Carvalho, Arthur Pimentel, primary, Dos Santos, Harison Franca, additional, Ribeiro, Gabriel Deltrejo, additional, Hiranobe, Carlos Toshiyuki, additional, Goveia, Danielle, additional, Gennaro, Elmer Mateus, additional, Paim, Leonardo Lataro, additional, and Dos Santos, Renivaldo José, additional

Published
2024
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12. A Review of EPDM (Ethylene Propylene Diene Monomer) Rubber-Based Nanocomposites: Properties and Progress.

Author

Costa, Naiara Lima, Hiranobe, Carlos Toshiyuki, Cardim, Henrique Pina, Dognani, Guilherme, Sanchez, Juan Camilo, Carvalho, Jaime Alberto Jaramillo, Torres, Giovanni Barrera, Paim, Leonardo Lataro, Pinto, Leandro Ferreira, Cardim, Guilherme Pina, Cabrera, Flávio Camargo, dos Santos, Renivaldo José, and Silva, Michael Jones

Subjects
*NANOCOMPOSITE materials, *ARTIFICIAL rubber, *PROPENE, *ETHYLENE, *MONOMERS
Abstract

Ethylene propylene diene monomer (EPDM) is a synthetic rubber widely used in industry and commerce due to its high thermal and chemical resistance. Nanotechnology has enabled the incorporation of nanomaterials into polymeric matrixes that maintain their flexibility and conformation, allowing them to achieve properties previously unattainable, such as improved tensile and chemical resistance. In this work, we summarize the influence of different nanostructures on the mechanical, thermal, and electrical properties of EPDM-based materials to keep up with current research and support future research into synthetic rubber nanocomposites. [ABSTRACT FROM AUTHOR]

Published
2024
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13. Recycling waste polyurethane from the refrigeration industry as filler in SBR / NR composites for industrial applications

Author

Hiranobe, Carlos Toshiyuki, primary, Tolosa, Gabrieli Roefero, additional, Santos, Gleyson Tadeu de Almeida, additional, de Oliveira, João Pedro Jenson, additional, Budemberg, Eduardo Roque, additional, Silva, Michael Jones da, additional, Cabrera, Flávio Camargo, additional, Job, Aldo Eloizo, additional, Paim, Leonardo Lataro, additional, Torres, Giovanni Barrera, additional, and Santos, Renivaldo José dos, additional

Published
2023
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14. Physical-Mechanical Properties of Chartwell® Coupling Agent-Treated Calcium Carbonate and Silica-Reinforced Hybrid Natural Rubber Composites

Author

Ribeiro, Gabriel Deltrejo, primary, Hiranobe, Carlos Toshiyuki, additional, da Silva, José Francisco Resende, additional, Torres, Giovanni Barrera, additional, Paim, Leonardo Lataro, additional, Job, Aldo Eloizo, additional, Cabrera, Flávio Camargo, additional, and dos Santos, Renivaldo José, additional

Published
2022
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15. Recycling waste polyurethane from the refrigeration industry as filler in SBR/NR composites for industrial applications.

Author

Hiranobe, Carlos Toshiyuki, Tolosa, Gabrieli Roefero, de Almeida Santos, Gleyson Tadeu, de Oliveira, João Pedro Jenson, Budemberg, Eduardo Roque, da Silva, Michael Jones, Cabrera, Flávio Camargo, Job, Aldo Eloizo, Paim, Leonardo Lataro, Torres, Giovanni Barrera, and dos Santos, Renivaldo José

Subjects
POLYURETHANES, RUBBER, POLYBUTADIENE, SHOE soles, STRESS-strain curves, INDUSTRIAL applications, WASTE recycling
Abstract

The refrigeration industry produces millions of tons of waste polyurethane (PU) every year, which can cause environmental damage and human health problems. This article analyzes the use of waste PU as filler in composites made of styrene butadiene rubber (SBR) and natural rubber (NR) to produce shoe soles. The interfacial interaction of said filler was evaluated by the Flory–Rehner method (swelling) using the equation developed by Lorenz–Park. The results of this evaluation were later compared with those obtained by the Mooney–Rivlin method using the data from stress–strain tests. According to the results of the tensile strength tests, the composites filled with waste PU present stress–strain curves that are like those of metallic materials that have low elastic strength but high plastic strength. Using the Lorenz–Park equation, the filled composites examined in this study exhibited values above 0.7, which means a strong filler–rubber interaction. Scanning Electron Microscopy and Fourier‐Transform Infrared Spectroscopy were used to investigate the morphology of the composites in detail. [ABSTRACT FROM AUTHOR]

Published
2023
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16. Fluid Phase Behavior of the Licuri (Syagrus coronata) Fatty Acid Ethyl Ester + Glycerol + Ethanol Mixtures at Different Temperatures—Experimental and Thermodynamic Modeling.

Author

Toledo, Iza Estevam Pedrosa, Coêlho, Dayana de Gusmão, Meili, Lucas, Hiranobe, Carlos Toshiyuki, Corazza, Marcos Lúcio, Arce, Pedro, da Silva, Erivaldo Antônio, de Carvalho, Sandra Helena Vieira, dos Santos, Renivaldo José, Soletti, João Inácio, and Ferreira-Pinto, Leandro

Subjects
FATTY acid esters, STANDARD deviations, PHASE equilibrium, ATMOSPHERIC pressure, MANUFACTURING processes, ETHANOL
Abstract

This study provides experimental insights into the liquid–liquid equilibrium (LLE) of a system consisting of fatty acid ethyl ester (FAEE) derived from licuri oil, glycerol, and ethanol, evaluated at various temperatures and standard atmospheric pressures. FAEE was synthesized through transesterification of licuri oil using NaOH as a catalyst. The liquid phase compositions were assessed via titration, and the results were consistent with the solubility curves and overall compositions. Data reliability was confirmed using Hand and Othmer-Tobias correlations, with a determination coefficient (R2) of 1, validating the dependability of the results. The NRTL model was employed to correlate the LLE data, yielding a root-mean-square deviation (RMSD) of approximately 1.20%, signifying a strong correlation with experimental uncertainties. The selectivity (S) and distribution (D) parameters indicated the efficacy of glycerol in the system, with S values exceeding 1 under all conditions tested. This investigation is crucial for biodiesel production, highlighting the potential of licuri oil as a renewable feedstock and the importance of phase equilibrium studies in the separation processes of biodiesel production products. [ABSTRACT FROM AUTHOR]

Published
2024
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18. Residuos sólidos urbanos de la poda de césped como fuente de energía alternativa: un estudio de caso en la ciudad de Rosana

Author

Mendonça, Caio, Oliveira, João Pedro Jenson de, Hiranobe, Carlos Toshiyuki, Santos, Renivaldo José dos, and Paim, Leonardo Lataro

Subjects
Urban Solid Waste, PCS, Potencial energético, Bioenergia, Biomasa, HHV, Bioenergy, Biomass, Residuos Sólidos Urbanos, Biomassa, Energy potential, Resíduo Sólido Urbano
Abstract

The aim of this work was to study urban solid waste from grass pruning (RSPG) at District of Primavera, in Rosana-SP, using gravimetric and calorimetric methods to evaluate the feasibility of using it as an energy source in direct combustion processes. RSPG samples were collected, washed, dried in air for 24h, fractionated in a knife mill and selected in a granulometric sieve before gravimetric and calorimetric analyses. Analyzes of moisture, total solids, aqueous and alcoholic extractives, ash, structural and non-structural inorganics, total inorganics, and higher heating value (HHV) were carried out. The aqueous and alcoholic extraction processes were carried out in an ultrasonic bath and presented values of 14.32 ± 0.28% for aqueous extractives and 6.65 ± 0.40% for alcoholic extracts. The samples showed values of structural inorganics and non-structural inorganics of 2.97±0.17% and 1.26±0.12%, respectively. RSPG proved to be an alternative as solid fuel by presenting a HHV value of 17.59±0.43 MJ kg-1 which is like other solid wastes. El objetivo de este trabajo fue estudiar los residuos sólidos urbanos de la poda de gramíneas (RSPG) en el Distrito de Primavera, en Rosana-SP, utilizando métodos gravimétricos y calorimétricos para evaluar la factibilidad de utilizarlos como fuente de energía en procesos de combustión directa. Las muestras de RSPG se recolectaron, lavaron, secaron al aire durante 24 h, se fraccionaron en un molino de cuchillas y se seleccionaron en un tamiz granulométrico antes de los análisis gravimétricos y calorimétricos. Se realizaron análisis de humedad, sólidos totales, extractos acuosos y alcohólicos, cenizas, inorgánicos estructurales y no estructurales, inorgánicos totales y poder calorífico superior (PCS). Los procesos de extracción acuosa y alcohólica se realizaron en baño ultrasónico y presentaron valores de 14,32 ± 0,28% para extractos acuosos y 6,65 ± 0,40% para extractos alcohólicos. Las muestras presentaron valores de inorgánicos estructurales e inorgánicos no estructurales de 2.97 ± 0.17% y 1.26 ± 0.12%, respectivamente. El RSPG demostró ser una alternativa como combustible sólido al presentar un valor de PCS de 17,59 ± 0,43 MJ kg-1 que es similar a otros residuos sólidos. O objetivo deste trabalho foi estudar os resíduos sólidos urbanos de poda de gramíneas (RSPG) do Distrito de Primavera, no município de Rosana-SP através de métodos gravimétricos e calorimétrico para avaliar a viabilidade de utilização como fonte de energia em processos de combustão direta. As amostras de RSPG foram coletadas, lavadas, secas ao ar por 24h, fracionadas em moinho de facas e selecionadas em peneira granulométrica antes das análises gravimétricas e calorimétrica. Foram realizadas análises de umidade, sólidos totais, extrativos aquoso e alcoólico, cinzas, inorgânicos estruturais e não-estruturais, inorgânicos totais e poder calorífico superior (PCS). O processo de extração aquosa e alcoólica foram realizados em banho ultrassônico e apresentaram os valores de 14,32 ± 0,28 % para os extrativos aquosos e 6,65 ± 0,40 % para os extrativos alcoólicos. As amostras apresentaram valores de inorgânicos estruturais e inorgânicos não estruturais de 2,97±0,17% e 1,26±0,12%, respectivamente. O RSPG apresentou ser alternativa como combustível sólido ao apresentar um valor de PCS de 17,59±0,43 MJ kg-1 que é similar a outros resíduos sólidos.

Published
2021

20. Mechanical and rheological properties of partial replacement of carbon black by treated ultrafine calcium carbonate in natural rubber compounds

Author

de Maria, Vitor Peixoto Klienchen, primary, de Paiva, Fábio Friol Guedes, additional, Cabrera, Flávio Camargo, additional, Hiranobe, Carlos Toshiyuki, additional, Ribeiro, Gabriel Deltrejo, additional, Paim, Leonardo Lataro, additional, Job, Aldo Eloizo, additional, and dos Santos, Renivaldo José, additional

Published
2021
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21. Physical-Mechanical Properties of Chartwell ® Coupling Agent-Treated Calcium Carbonate and Silica-Reinforced Hybrid Natural Rubber Composites.

Author

Ribeiro, Gabriel Deltrejo, Hiranobe, Carlos Toshiyuki, da Silva, José Francisco Resende, Torres, Giovanni Barrera, Paim, Leonardo Lataro, Job, Aldo Eloizo, Cabrera, Flávio Camargo, and dos Santos, Renivaldo José

Subjects
CALCIUM carbonate, RUBBER, REINFORCEMENT of rubber, VULCANIZATION, BIOPOLYMERS
Abstract

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 advantages for this industry. Treated calcium carbonate was able to link the inorganic and organic parts of the composite due to its bifunctionality; hence, it can be used as a filler to partially replace silica in hybrid NR composites. [ABSTRACT FROM AUTHOR]

Published
2022
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24. Density evaluation of crosslinking in natural rubber in different vulcanization systems using mechanical tests

Author

Hiranobe, Carlos Toshiyuki, Universidade Estadual Paulista (Unesp), Santos, Renivaldo José dos [UNESP], and Paim, Leonardo Lataro [UNESP]

Subjects
Borracha natural, Crosslinking, Inchamento, Ressonância magnética nuclear, Mechanical properties, Reticulação, Swelling, Propriedades mecânicas, Natural rubber, Nuclear magnetic resonance
Abstract

Submitted by Carlos Toshiyuki Hiranobe (carlos.hiranobe@unesp.br) on 2020-04-02T16:27:02Z No. of bitstreams: 1 Dissertação Carlos Toshiyuki Hiranobe.pdf: 2623057 bytes, checksum: 6b153d860f93b85d6ffe16d9ed0c4251 (MD5) Submitted by Carlos Toshiyuki Hiranobe (carlos.hiranobe@unesp.br) on 2020-04-02T16:27:02Z No. of bitstreams: 1 Dissertação Carlos Toshiyuki Hiranobe.pdf: 2623057 bytes, checksum: 6b153d860f93b85d6ffe16d9ed0c4251 (MD5) Approved for entry into archive by Lucilene Cordeiro da Silva Messias null (lubiblio@bauru.unesp.br) on 2020-04-02T17:17:41Z (GMT) No. of bitstreams: 1 hiranobe_ct_me_bauru.pdf: 2534090 bytes, checksum: 5b47ca82b59753805d1d45fd5819e0f3 (MD5) Submitted by Carlos Toshiyuki Hiranobe (carlos.hiranobe@unesp.br) on 2020-04-02T16:27:02Z No. of bitstreams: 1 Dissertação Carlos Toshiyuki Hiranobe.pdf: 2623057 bytes, checksum: 6b153d860f93b85d6ffe16d9ed0c4251 (MD5) Approved for entry into archive by Lucilene Cordeiro da Silva Messias null (lubiblio@bauru.unesp.br) on 2020-04-02T17:17:41Z (GMT) No. of bitstreams: 1 hiranobe_ct_me_bauru.pdf: 2534090 bytes, checksum: 5b47ca82b59753805d1d45fd5819e0f3 (MD5) Submitted by Carlos Toshiyuki Hiranobe (carlos.hiranobe@unesp.br) on 2020-04-02T16:27:02Z No. of bitstreams: 1 Dissertação Carlos Toshiyuki Hiranobe.pdf: 2623057 bytes, checksum: 6b153d860f93b85d6ffe16d9ed0c4251 (MD5) Approved for entry into archive by Lucilene Cordeiro da Silva Messias null (lubiblio@bauru.unesp.br) on 2020-04-02T17:17:41Z (GMT) No. of bitstreams: 1 hiranobe_ct_me_bauru.pdf: 2534090 bytes, checksum: 5b47ca82b59753805d1d45fd5819e0f3 (MD5) Made available in DSpace on 2020-04-02T17:17:41Z (GMT). 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No. of bitstreams: 1 hiranobe_ct_me_bauru.pdf: 2534090 bytes, checksum: 5b47ca82b59753805d1d45fd5819e0f3 (MD5) Previous issue date: 2020-01-31 Approved for entry into archive by Lucilene Cordeiro da Silva Messias null (lubiblio@bauru.unesp.br) on 2020-04-02T17:17:41Z (GMT) No. of bitstreams: 1 hiranobe_ct_me_bauru.pdf: 2534090 bytes, checksum: 5b47ca82b59753805d1d45fd5819e0f3 (MD5) Made available in DSpace on 2020-04-02T17:17:41Z (GMT). No. of bitstreams: 1 hiranobe_ct_me_bauru.pdf: 2534090 bytes, checksum: 5b47ca82b59753805d1d45fd5819e0f3 (MD5) Previous issue date: 2020-01-31 Submitted by Carlos Toshiyuki Hiranobe (carlos.hiranobe@unesp.br) on 2020-04-02T16:27:02Z No. of bitstreams: 1 Dissertação Carlos Toshiyuki Hiranobe.pdf: 2623057 bytes, checksum: 6b153d860f93b85d6ffe16d9ed0c4251 (MD5) Made available in DSpace on 2020-04-02T17:17:41Z (GMT). No. of bitstreams: 1 hiranobe_ct_me_bauru.pdf: 2534090 bytes, checksum: 5b47ca82b59753805d1d45fd5819e0f3 (MD5) Previous issue date: 2020-01-31 Made available in DSpace on 2020-04-02T17:17:41Z (GMT). No. of bitstreams: 1 hiranobe_ct_me_bauru.pdf: 2534090 bytes, checksum: 5b47ca82b59753805d1d45fd5819e0f3 (MD5) Previous issue date: 2020-01-31 Approved for entry into archive by Lucilene Cordeiro da Silva Messias null (lubiblio@bauru.unesp.br) on 2020-04-02T17:17:41Z (GMT) No. of bitstreams: 1 hiranobe_ct_me_bauru.pdf: 2534090 bytes, checksum: 5b47ca82b59753805d1d45fd5819e0f3 (MD5) Approved for entry into archive by Lucilene Cordeiro da Silva Messias null (lubiblio@bauru.unesp.br) on 2020-04-02T17:17:41Z (GMT) No. of bitstreams: 1 hiranobe_ct_me_bauru.pdf: 2534090 bytes, checksum: 5b47ca82b59753805d1d45fd5819e0f3 (MD5) Approved for entry into archive by Lucilene Cordeiro da Silva Messias null (lubiblio@bauru.unesp.br) on 2020-04-02T17:17:41Z (GMT) No. of bitstreams: 1 hiranobe_ct_me_bauru.pdf: 2534090 bytes, checksum: 5b47ca82b59753805d1d45fd5819e0f3 (MD5) Approved for entry into archive by Lucilene Cordeiro da Silva Messias null (lubiblio@bauru.unesp.br) on 2020-04-02T17:17:41Z (GMT) No. of bitstreams: 1 hiranobe_ct_me_bauru.pdf: 2534090 bytes, checksum: 5b47ca82b59753805d1d45fd5819e0f3 (MD5) Made available in DSpace on 2020-04-02T17:17:41Z (GMT). No. of bitstreams: 1 hiranobe_ct_me_bauru.pdf: 2534090 bytes, checksum: 5b47ca82b59753805d1d45fd5819e0f3 (MD5) Previous issue date: 2020-01-31 Made available in DSpace on 2020-04-02T17:17:41Z (GMT). No. of bitstreams: 1 hiranobe_ct_me_bauru.pdf: 2534090 bytes, checksum: 5b47ca82b59753805d1d45fd5819e0f3 (MD5) Previous issue date: 2020-01-31 Submitted by Carlos Toshiyuki Hiranobe (carlos.hiranobe@unesp.br) on 2020-04-02T16:27:02Z No. of bitstreams: 1 Dissertação Carlos Toshiyuki Hiranobe.pdf: 2623057 bytes, checksum: 6b153d860f93b85d6ffe16d9ed0c4251 (MD5) Approved for entry into archive by Lucilene Cordeiro da Silva Messias null (lubiblio@bauru.unesp.br) on 2020-04-02T17:17:41Z (GMT) No. of bitstreams: 1 hiranobe_ct_me_bauru.pdf: 2534090 bytes, checksum: 5b47ca82b59753805d1d45fd5819e0f3 (MD5) Approved for entry into archive by Lucilene Cordeiro da Silva Messias null (lubiblio@bauru.unesp.br) on 2020-04-02T17:17:41Z (GMT) No. of bitstreams: 1 hiranobe_ct_me_bauru.pdf: 2534090 bytes, checksum: 5b47ca82b59753805d1d45fd5819e0f3 (MD5) Made available in DSpace on 2020-04-02T17:17:41Z (GMT). No. of bitstreams: 1 hiranobe_ct_me_bauru.pdf: 2534090 bytes, checksum: 5b47ca82b59753805d1d45fd5819e0f3 (MD5) Previous issue date: 2020-01-31 Made available in DSpace on 2020-04-02T17:17:41Z (GMT). No. of bitstreams: 1 hiranobe_ct_me_bauru.pdf: 2534090 bytes, checksum: 5b47ca82b59753805d1d45fd5819e0f3 (MD5) Previous issue date: 2020-01-31 Made available in DSpace on 2020-04-02T17:17:41Z (GMT). No. of bitstreams: 1 hiranobe_ct_me_bauru.pdf: 2534090 bytes, checksum: 5b47ca82b59753805d1d45fd5819e0f3 (MD5) Previous issue date: 2020-01-31 Made available in DSpace on 2020-04-02T17:17:41Z (GMT). No. of bitstreams: 1 hiranobe_ct_me_bauru.pdf: 2534090 bytes, checksum: 5b47ca82b59753805d1d45fd5819e0f3 (MD5) Previous issue date: 2020-01-31 Approved for entry into archive by Lucilene Cordeiro da Silva Messias null (lubiblio@bauru.unesp.br) on 2020-04-02T17:17:41Z (GMT) No. of bitstreams: 1 hiranobe_ct_me_bauru.pdf: 2534090 bytes, checksum: 5b47ca82b59753805d1d45fd5819e0f3 (MD5) Approved for entry into archive by Lucilene Cordeiro da Silva Messias null (lubiblio@bauru.unesp.br) on 2020-04-02T17:17:41Z (GMT) No. of bitstreams: 1 hiranobe_ct_me_bauru.pdf: 2534090 bytes, checksum: 5b47ca82b59753805d1d45fd5819e0f3 (MD5) Made available in DSpace on 2020-04-02T17:17:41Z (GMT). No. of bitstreams: 1 hiranobe_ct_me_bauru.pdf: 2534090 bytes, checksum: 5b47ca82b59753805d1d45fd5819e0f3 (MD5) Previous issue date: 2020-01-31 Made available in DSpace on 2020-04-02T17:17:41Z (GMT). No. of bitstreams: 1 hiranobe_ct_me_bauru.pdf: 2534090 bytes, checksum: 5b47ca82b59753805d1d45fd5819e0f3 (MD5) Previous issue date: 2020-01-31 Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Pró-Reitoria de Pós-Graduação (PROPG UNESP) Propriedades mecânicas e térmicas da borracha natural (BN) podem ser modificadas no processo de vulcanização, variando-se as quantidades de enxofre e acelerador para atender as especificações desejadas. A influência da taxa acelerador/enxofre foi analisada e suas propriedades mecânicas foram comparadas de acordo com o desempenho de cada uma nos respectivos sistemas de reticulação. Preparou-se compostos de BN reticulados com enxofre por três sistemas de vulcanização: convencional (CV), semieficiente (SEV) e eficiente (EV). Os sistemas foram processados utilizando MBTS (dissulfeto de dibenzotiazol), TMTD (dissulfeto de tetrametiltiuram) e CBS (n-ciclohexil 2-benzotiazol sulfenamida). As misturas foram preparadas em misturador aberto de rolos, de acordo com a norma ASTM D3182. A caracterização foi realizada por meio da reometria (ASTM D2084), ensaios mecânicos e térmicos, envelhecimento acelerado e determinação das densidades de ligações cruzadas por inchamento, análise dinâmico mecânica, ensaio de tração e por ressonância magnética nuclear utilizando hidrogênio em baixo campo magnético (RMN1H). O sistema SEV, utilizando TMTD e CBS, foi o que apresentou resultados superiores nos tempos de cura e nas propriedades mecânicas como a rigidez, dureza, abrasão e resistência à tração. Quando utilizado o MBTS, obteve-se vulcanizados com grande resistência quanto à deformação, além de apresentar pós-cura no processo de envelhecimento acelerado. O sistema de cura não alterou a estrutura físico-química dos vulcanizados. Observou-se, ainda, por meio dos ensaios de DMA que o aumento da densidade de reticulação aumenta a temperatura de transição vítrea do composto vulcanizado. The vulcanization process can modify mechanical and thermal properties of natural rubber (NR) by varying the amount of sulfur and accelerator to meet the preferred specifications. The influence of the accelerator/sulfur rate was analyzed and its mechanical properties were compared according to the performance of each one on the respective crosslinking systems. NR composites crosslinked with sulfur were prepared by three systems: conventional (CV), semi-efficient (SEV) and efficient (EV). The systems were processed using MBTS (dibenzothiazole disulfide), TMTD (tetramethyltiuram disulfide) and CBS (n-cyclohexyl 2-benzothiazole sulfenamide). The mixtures were prepared in an open rolled mixer, following the ASTM D3182 standard. The characterization was carried out by rheometry (ASTM D2084), mechanical and thermal tests, accelerated aging and crosslinking density determination by swelling, dynamic mechanical analysis, tensile tests and nuclear magnetic resonance tests using hydrogen in low magnetic field (NMR1H). The SEV system, using TMTD and CBS, was the one that has presented superior results in curing times and mechanical properties, such as rigidity, hardness, abrasion and tensile strength. Vulcanized composites with great resistance to deformation and presenting post-cure in the accelerated aging process were obtained using MBTS. The curing system did not alter their physical-chemical structure. It was also observed, through DMA tests, that the increasing in the crosslinking density increases the glass transition temperature of the vulcanized composites. CAPES 23038.017963/2017-77 PROPG UNESP número 244/2018

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2020

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