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Microstructural analysis of carbon nanomaterials produced from pyrolysis/combustion of Styrene-Butadiene-Rubber (SBR)

ALVES, Joner Oliveira; ZHUO, Chuanwei; LEVENDIS, Yiannis Angelo; TENÓRIO, Jorge Alberto Soares
Fonte: ABM, ABC, ABPol Publicador: ABM, ABC, ABPol
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
70.47457%
Styrene-Butadiene-Rubber (SBR) is a synthetic rubber copolymer used to fabricate several products. This study aims to demonstrate the use of SBR as feedstock for carbon nanomaterials (nanofibers and nanotubes) growth, and therefore to establish a novel process for destination of waste products containing SBR. A three stage electrically heated flow reactor was used. Small pellets of rubber were pyrolyzed at a temperature of 1000 ºC. The pyrolyzates were mixed with oxygen-containing gases and were burned. The products of combustion were used to synthesize the carbon nanomaterials (CNMs) at the presence of a catalyst. CNMs have a wide range of potential applications due to their extraordinary mechanical, thermal and electrical properties. Produced materials were characterized by SEM and TEM, whereas combustion products were assessed using GC. Results showed that CNMs with outer diameters of 30-100 nm and lengths of about 30 µm were formed. Therefore, it was demonstrated that waste products containing SBR can be used to generate CNMs which are value-added products of intense technological interest.; CNPQ; Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior (CAPES)

Effect of the processing conditions and the addition of trans-polyoctenylene rubber on the properties of natural rubber/styrene-butadiene rubber blends

BIZI, Claudia Maria Pena; DEMARQUETTE, Nicole R.
Fonte: JOHN WILEY & SONS INC Publicador: JOHN WILEY & SONS INC
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
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In this study, the influence of the processing conditions and the addition of trans-polyoctenylene rubber (TOR) on Mooney viscosity, tensile properties, hardness, tearing resistance, and resilience of natural rubber/styrene-butadiene rubber blends was investigated. The results obtained are explained in light of dynamic mechanical and morphological analyses. Increasing processing time produced a finer blend morphology, which resulted in an improvement in the mechanical properties. The addition of TOR involved an increase in hardness, a decrease in tear resistance, and no effect on the resilience. It resulted in a large decrease in the Mooney viscosity and a slight decrease in the tensile properties if the components of the compounds were not properly mixed. The results indicate that TOR acted more as a plasticizer than a compatibilizer. (c) 2008 Wiley Periodicals, Inc.

Chemical Modifications in Styrene-Butadiene Rubber after Microwave Devulcanization

Hirayama, Denise; Saron, Clodoaldo
Fonte: AMER CHEMICAL SOC; WASHINGTON Publicador: AMER CHEMICAL SOC; WASHINGTON
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
80.632017%
Microwave devulcanization has been studied as a method for elastomer recycling, which is based on the conversion of the reticulated and infusible structure of thermosetting rubbers in free polymeric chains able to be remolded by thermomechanical processing in recycling operations for the manufacture of other products. Elastomeric wastes are often irregularly discarded in nature, producing serious environmental damage, and their mechanical recycling is still considered a challenge. Thus, the development of alternatives for elastomer recycling is directly related to the actions of sustainable development and economic benefits to companies that pay to discard their wastes. The aim of this work is to evaluate the chemical modifications occurring in styrene butadiene rubber (SBR) after microwave devulcanization. Compounds of SBR were vulcanized in the presence of vulcanization agents and variable amounts of carbon black, and then the rubbers were milled and submitted to microwave treatment. Only the SBR with high carbon black content shows some portion of devulcanized material. However, the rubber with lower content of carbon black which was devulcanized by microwave radiation shows an increase in cross-link density. The microwave treatment also causes cross-link breaks mainly in polysulfidic bonds as well as decomposition of chemical groups containing sulfur attached to the chemical structure of SBR...

Efeito das condições de processamento e da adição de borracha trans-polioctenileno nas propriedades de blendas de borracha natural/estireno butadieno.; Effect of processing ponditions and addition of trans-polyoctenylene rubber on the properties of natural rubber/styrene butadiene rubber blends.

Bizi, Claudia Maria Pena
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 04/10/2007 PT
Relevância na Pesquisa
59.654243%
Blendas poliméricas são largamente utilizadas nas indústrias de pneus por causa de seu baixo custo e das melhores propriedades que podem ser obtidas. Quando os componentes da blenda não são miscíveis entre si, métodos de compatibilização química (utilizando agentes compatibilizantes) ou mecânica (aumentando o tempo de mistura dos elastômeros) são necessários para melhorar a compatibilidade dos componentes da mistura. Neste trabalho, o Trans-Polioctenileno (TOR) foi usado como agente compatibilizante da blenda de NR/SBR. A viscosidade Mooney, a Carga e o Alongamento na Ruptura de diversas blendas foram avaliados, utilizando um planejamento fatorial. Os resultados obtidos mostraram que o TOR tem maior influência na alteração da viscosidade Mooney, seguido pelo tempo de premix e de repasse. No caso das propriedades dinamométricas, a carga e o alongamento na ruptura são mais sensíveis às alterações do tempo de processamento dos polímeros. O TOR leva a uma ligeira diminuição destas propriedades. Baseado nos resultados estatísticos, equações de regressão para avaliar as propriedades estudadas em função da concentração de TOR e do tempo de processamento foram propostos e posteriormente verificados, utilizando blendas que não estavam incluídas no planejamento original. Os resultados foram bastante satisfatórios...

Caracterização da sílica amorfa extraída da casca de arroz obtida por pré-hidrólise ácida e calcinação, e sua aplicação em borracha de estireno-butadieno (SBR); Characterization of amorphous rice husk silica obtained by acidic prehydrolysis and calcination, and its application in styrene-butadiene rubber (SBR)

Budemberg, Eduardo Roque
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 14/06/2013 PT
Relevância na Pesquisa
101.19411%
O crescimento dos países em desenvolvimento aumentará em várias vezes o consumo de energia, materiais e alimentos. Para suprir essa demanda é necessário o aproveitamento racional dos resíduos gerados por processos industriais, agrícolas e lixo urbano, transformando-os em energia economicamente competitiva com as outras formas de energia, e em materiais com propriedades otimizadas. O objetivo do presente trabalho foi comparar o comportamento da sílica da casca de arroz obtida por pré-hidrólise ácida seguida de calcinação controlada (Sil-PH) com sílicas de casca de arroz comerciais obtidas simplesmente pela queima da casca (Sil-B e Sil-C) e com a sílica comercial obtida da areia quartzítica (Sil-Z), como carga de reforço em borracha de estireno-butadieno (SBR), que é a mais usada na indústria de fabricação de pneus. Estudos foram conduzidos em SBR 1502, preparados conforme norma ASTM 3191-2010. Foram adicionadas à borracha as sílicas em concentrações de 0, 10, 20 e 40 ppcb. Foram conduzidos testes físicos, químicos, mecânicos, reométricos, dinâmico-mecânicos e análise térmica, bem como ensaios de inchamento dos corpos de prova em toluol e análise microestrutural das sílicas e dos compostos por microscopia eletrônica de varredura...

NMR study of styrene-butadiene rubber (SBR) and TiO2 nanocomposites

Arantes, Tatiane M.; Leao, Katyuscya V.; Tavares, Maria Ines B.; Ferreira, Antonio Gilberto; Longo, Elson; Camargo, Emerson R.
Fonte: Elsevier B.V. Publicador: Elsevier B.V.
Tipo: Artigo de Revista Científica Formato: 490-494
ENG
Relevância na Pesquisa
70.12031%
Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP); Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES); The chemical behavior of styrene-butadiene rubber (SBR) and of the SBR/TiO2 and photodegraded SBR/TiO2 nanocomposites was investigated through nuclear magnetic resonance spectroscopy (NMR) in the solid state with magic angle spinning (MAS). The C-13 cross polarization/magic angle spinning (CP/MAS) routine spectrum allowed us to obtain information on the polymer microstructure and also to evaluate the domain mobilities. The variation contact time and the proton spin-lattice relaxation time in the rotating frame (T,pH) were determinant factors to evaluate the dynamic molecular motion. The NMR spectrum of the nanocomposites was dislocated 5 ppm to higher chemical shift, indicating the presence of a strong interaction between the polymer chains and the TiO2 nanoparticles. The VTC experiment showed a rigid domain in the SBR/TiO2 photodegraded nanocomposite due to cross-linking reactions. (C) 2009 Elsevier Ltd. All rights reserved.

Nanocomposites of Styrene-Butadiene Rubber and Synthetic Anatase Obtained by a Colloidal Route and Their Photooxidation

Arantes, Tatiane M.; Leite, Edson R.; Longo, Elson; Camargo, Emerson R.
Fonte: John Wiley & Sons Inc Publicador: John Wiley & Sons Inc
Tipo: Artigo de Revista Científica Formato: 1898-1904
ENG
Relevância na Pesquisa
80.60745%
Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP); Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq); Photodegradable styrene-butadiene rubber (SBR)/TiO(2) nanocomposites were prepared by a colloidal route through the simple mixing of a commercial polymer latex and synthetic anatase nanoparticles. Stable colloids of pure anatase TiO(2) nanoparticles with an average diameter of 7 nm were prepared by a solvothermal route from the hydrolysis of titanium alkoxide by hydrogen peroxide in the presence of oleic acid. The photocatalytic degradation of the SBR-TiO(2) nanocomposites was carried out in ambient air at room temperature under a UV lamp and was monitored by Fourier transform infrared and UV-visible spectroscopies and differential scanning calorimetry. The results show that the SBR-TiO(2) nanocomposites were photocatalytically degraded under UV light, which indicate that the butadiene chains in the nanocomposite were oxidized during UV irradiation. Thermal analysis measurements indicated that crosslinking reactions occurred. The presence of anatase TiO(2) nanoparticles was found to accelerate the photocatalytic process, and the degradation mechanism was similar to that of the pure SBR polymer. (C) 2009 Wiley Periodicals...

Comparison of the nanoparticles performance in the photocatalytic degradation of a styrene-butadiene rubber nanocomposite

Arantes, Tatiane M.; Sala, Renata L.; Leite, Edson R.; Longo, Elson; Camargo, Emerson R.
Fonte: Universidade Estadual Paulista Publicador: Universidade Estadual Paulista
Tipo: Artigo de Revista Científica Formato: 2368-2374
ENG
Relevância na Pesquisa
101.07815%
Much has been talking about the advantages of polymeric nanocomposites, but little is known about the influence of nanoparticles on the stability of these materials. In this sense, we studied the influence of both oxides of zirconium and titanium, known to have photocatalytic properties, as well as the influence of synthetic clay Laponite on the photodegradation of styrene-butadiene rubber (SBR). SBR nanocomposites were prepared by the colloidal route by mixing commercial polymer lattices and nanometric anatase TiO2, monoclinic ZrO2 or exfoliated Laponite clays colloidal suspensions. To better understand the degradation mechanisms that occur in these nanocomposites, the efficiency of different photocatalysts under ultraviolet radiation was monitored by FT-IR and UV-vis spectroscopies and by differential scanning calorimetric. It was observed that TiO2 and ZrO2 nanoparticles undoubtedly acted as catalysts during the photodegradation process with different efficiencies and rates. However, when compared to pure SBR samples, the polymer degradation mechanism was unaffected. Unlike studies with nanocomposites montmorillonite, exfoliated laponite clay effectively acts as a photostabilizer of polymer UV photodegradation. Copyright © 2012 Wiley Periodicals...

The use of styrene-butadiene rubber waste as a potential filler in nitrile rubber: order of addition and size of waste particles

Baeta,D. A.; Zattera,J. A.; Oliveira,M. G.; Oliveira,P. J.
Fonte: Brazilian Society of Chemical Engineering Publicador: Brazilian Society of Chemical Engineering
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/03/2009 EN
Relevância na Pesquisa
70.632017%
Styrene-butadiene rubber (SBR) has large applications in the shoe industry, especially as expanded sheets used to produce insoles and inner soles. According to TG analysis, the rubber content in SBR residues (SBR-r) was found to be around 26-wt%. Based on that data, a cost-effective technique for the reuse of SBR-r in Nitrile rubber (NBR) was developed. Later, the effect of SBR-r on the cure behavior, mechanical performance, swelling, and crosslink density of reused rubber was investigated, with more emphasis placed on the effect of both particle size and loading of waste filler. Cure characteristics such as optimum cure time and scorch time were then reduced by the increasing amount of SBR-r filler. Owing to the reinforced nature of the largest particle size SBR-r, the best results for the mechanical properties of NBR were those in which SBR-r was added at the end of the cure process. The study has thus shown that SBR residue (SBR-r) can be used as an economical alternative filler in NBR.

Microstructural analysis of carbon nanomaterials produced from pyrolysis/combustion of Styrene-Butadiene-Rubber (SBR)

Alves,Joner Oliveira; Zhuo,Chuanwei; Levendis,Yiannis Angelo; Tenório,Jorge Alberto Soares
Fonte: ABM, ABC, ABPol Publicador: ABM, ABC, ABPol
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/12/2011 EN
Relevância na Pesquisa
70.47457%
Styrene-Butadiene-Rubber (SBR) is a synthetic rubber copolymer used to fabricate several products. This study aims to demonstrate the use of SBR as feedstock for carbon nanomaterials (nanofibers and nanotubes) growth, and therefore to establish a novel process for destination of waste products containing SBR. A three stage electrically heated flow reactor was used. Small pellets of rubber were pyrolyzed at a temperature of 1000 ºC. The pyrolyzates were mixed with oxygen-containing gases and were burned. The products of combustion were used to synthesize the carbon nanomaterials (CNMs) at the presence of a catalyst. CNMs have a wide range of potential applications due to their extraordinary mechanical, thermal and electrical properties. Produced materials were characterized by SEM and TEM, whereas combustion products were assessed using GC. Results showed that CNMs with outer diameters of 30-100 nm and lengths of about 30 µm were formed. Therefore, it was demonstrated that waste products containing SBR can be used to generate CNMs which are value-added products of intense technological interest.

Assessment of 1,3-butadiene exposure in polymer production workers using HPRT mutations in lymphocytes as a biomarker.

Ammenheuser, M M; Bechtold, W E; Abdel-Rahman, S Z; Rosenblatt, J I; Hastings-Smith, D A; Ward, J B
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /12/2001 EN
Relevância na Pesquisa
50.552974%
1,3-Butadiene (BD), which is used to make styrene-butadiene rubber, is a potent carcinogen in mice and a probable carcinogen, associated with leukemia, in humans. We have previously used HPRT mutation as a biomarker to evaluate exposures to BD in a monomer production plant. We now report on a study of 49 workers in a styrene-butadiene rubber plant in which we used the concentration of the BD metabolite 1,2-dihydroxy-4-(N-acetylcysteinyl-S)-butane (M1) in urine as a biomarker of exposure and the frequency of HPRT variant (mutant) lymphocytes (Vf) as a biomarker of effect. Workers were assigned to high- and low-exposure groups based on historical information about work areas and jobs. Personal exposure to BD for one work shift was measured using a passive badge dosimeter. Each participant provided a urine specimen and blood sample at the end of the work shift and completed a questionnaire providing information on lifestyle, health, and work activities. The average BD exposures in the high- and low-exposure groups were significantly different, even after excluding two extreme values, (high 1.48 ppm; low 0.15 ppm, p < 0.002). This study was done in 1994 and 1995 before the establishment, in 1996, of the new permissible exposure limit of 1 ppm. Both the mean M1 and the HPRT Vf were more than three times greater in the high-exposure group than in the low-exposure group (p < 0.0005). The three end points correlated with each other...

Carcinogenicity of 1,3-butadiene.

Melnick, R L; Shackelford, C C; Huff, J
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /04/1993 EN
Relevância na Pesquisa
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1,3-Butadiene, a high-production volume chemical used largely in the manufacture of synthetic rubber, is a multiple organ carcinogen in rats and mice. In inhalation studies conducted in mice by the National Toxicology Program, high rates of early lethal lymphomas occurring at exposure levels of 625 ppm or higher reduced the development and expression of later developing tumors at other sites. Use of survival-adjusted tumor rates to account for competing risk factors provided a clearer indication of the dose responses for 1,3-butadiene-induced neoplasms. An increase in lung tumors in female mice was observed at exposure concentrations as low as 6.25 ppm, the lowest concentration ever used in a long-term carcinogenicity study of this gas. Human exposures to 1,3-butadiene by workers employed at facilities that produce this chemical and at facilities that produce styrene-butadiene rubber have been measured at levels higher than those that cause cancer in animals. Furthermore, epidemiology studies have consistently revealed associations between occupational exposure to 1,3-butadiene and excess mortality due to lymphatic and hematopoietic cancers. In response to the carcinogenicity findings for 1,3-butadiene in animals and in humans, the Occupational Safety and Health Administration has proposed lowering the occupational exposure standard for this chemical from 1000 ppm to 2 ppm. Future work is needed to understand the mechanisms of tumor induction by 1...

Assessment of 1,3-butadiene epidemiology studies.

Ott, M G
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /06/1990 EN
Relevância na Pesquisa
50.387524%
Positive carcinogenicity studies in mice and rats have led to concerns that 1,3-butadiene may be carcinogenic in humans under exposure conditions that have existed in occupational settings and perhaps exist today. The principal settings of interest are the styrene-butadiene rubber (SBR) manufacturing industry, which uses large quantities of 1,3-butadiene, and the 1,3-butadiene monomer industry. The potential for 1,3-butadiene exposure is highest during monomer transfer operations and is lowest in finishing areas of polymerization plants where the polymer products are processed. Three large cohort mortality studies have been conducted in the SBR and monomer producing industries since 1980. These studies, which examined the mortality experience of over 17,000 men employed in one monomer and 10 SBR facilities, are the subject of this review. All but one of the facilities began operations during the early 1940s. The mortality experience observed within these employee cohorts is comparable to that seen in other long-term studies of men employed in the petroleum, chemical, and rubber industries for all causes of death, total malignant neoplasms, and for the specific cancers seen in excess in the toxicologic studies. This paper discusses discrepant findings observed in more detailed analyses within individual cohorts and among employment subgroups...

The industrial production and use of 1,3-butadiene.

Morrow, N L
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /06/1990 EN
Relevância na Pesquisa
50.198193%
This presentation provides a brief overview of the production and use of 1,3-butadiene in the United States. Starting as a coproduct of ethylene, the 1,3-butadiene monomer is extracted and purified, then transferred to consumers. Major uses of 1,3-butadiene include the manufacture of styrene-butadiene rubber, polybutadiene rubber, and adiponitrile.

High Performance Graphene Oxide Based Rubber Composites

Mao, Yingyan; Wen, Shipeng; Chen, Yulong; Zhang, Fazhong; Panine, Pierre; Chan, Tung W.; Zhang, Liqun; Liang, Yongri; Liu, Li
Fonte: Nature Publishing Group Publicador: Nature Publishing Group
Tipo: Artigo de Revista Científica
Publicado em 26/08/2013 EN
Relevância na Pesquisa
50.47457%
In this paper, graphene oxide/styrene-butadiene rubber (GO/SBR) composites with complete exfoliation of GO sheets were prepared by aqueous-phase mixing of GO colloid with SBR latex and a small loading of butadiene-styrene-vinyl-pyridine rubber (VPR) latex, followed by their co-coagulation. During co-coagulation, VPR not only plays a key role in the prevention of aggregation of GO sheets but also acts as an interface-bridge between GO and SBR. The results demonstrated that the mechanical properties of the GO/SBR composite with 2.0 vol.% GO is comparable with those of the SBR composite reinforced with 13.1 vol.% of carbon black (CB), with a low mass density and a good gas barrier ability to boot. The present work also showed that GO-silica/SBR composite exhibited outstanding wear resistance and low-rolling resistance which make GO-silica/SBR very competitive for the green tire application, opening up enormous opportunities to prepare high performance rubber composites for future engineering applications.

Effects of the Amount of Fillers and of the Crosslink Density on the Mechanical Behavior of Carbon-Black Filled Styrene Butadiene Rubbers

MERCKEL, Yannick; DIANI, Julie; BRIEU, Mathias; CAILLARD, Julien
Fonte: Wiley Publicador: Wiley
EN
Relevância na Pesquisa
59.70163%
Several carbon-black filled styrene-butadiene rubbers are subjected to monotonic uniaxial tension tests in order to investi-gate the effects of the amount of fillers and of the crosslink density on their mechanical properties. The Young modulus, the volume changes associated with material damage and the stretch to failure are extracted and discussed. Results compare well to the literature results when exist and quantitative analysis are proposed when possible. Results show that filled rubbers are not incompressible when submitted to uniaxial tension tests and their volume changes are strongly dependent of the amount of fillers but are unaffected by the crosslink density. The latter shows strong impact on the filled rubbers stretch to failure but more interestingly this impact is com-parable to what is encountered in unfilled rubbers. The stretch to failure is improved by the addition of fillers with an optimum for material filled around 30 phr.

Micromechanical modeling of the linear viscoelasticity of carbon-black filled styrene butadiene rubbers: the role of the rubber-filler interphase

DIANI, Julie; GILORMINI, Pierre; MERCKEL, Yannick; VION-LOISEL, Fabien
Fonte: Elsevier Publicador: Elsevier
EN
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Version éditeur : http://www.sciencedirect.com/science/article/pii/S0167663612002190; Micromechanics modeling of the linear viscoelasticity of carbon-black filled styrene butadiene rubbers (SBR) shows that a simple representation of a spherical rigid-phase surrounded by rubber gum and embedded in an homogeneous equivalent medium provides access to the effective volume fraction of fillers. This simple representation is successful for a significant range of filler amount, and for materials in the glassy state. For materials in the rubbery state, experimental results support the existence of a filler-rubber interphase with reduced mobility due to confinement. The 4-phase micromechanics model, which accounts for a bounded rubber layer coating the fillers, provides satisfactory estimates of the linear viscoelasticity of filled rubbers from the rubbery state to the glassy state. It also provides access to the filler rubber interphase behavior that appears viscoelastic, and to an estimate of the interphase thickness.; ANR MATETPRO AMUFISE

Mortality from cancer and other causes of death among synthetic rubber workers

Sathiakumar, N.; Delzell, E.; Hovinga, M.; Macaluso, M.; Julian, J. A.; Larson, R.; Cole, P.; Muir, D. C.
Fonte: BMJ Group Publicador: BMJ Group
Tipo: Artigo de Revista Científica
Publicado em /04/1998 EN
Relevância na Pesquisa
51.778315%
OBJECTIVES: This study evaluated the mortality experience of workers from the styrene-butadiene rubber industry. Concerns about a possible association of 1,3-butadiene and styrene with lymphohaematopoietic, gastrointestinal, and lung cancers prompted the investigation. METHODS: A retrospective follow up study was conducted of 15,649 men employed for at least one year at any of eight North American styrene-butadiene rubber plants. Analyses used standardised mortality ratios (SMRs) to compare styrene-butadiene rubber workers' cause specific mortalities (1943-91) with those of the United States and Ontario general populations. RESULTS: On average, there were 25 years of follow up per subject. The standardised mortality ratio (SMR) was 87 (95% confidence interval (95% CI) 85 to 90) for all causes of death combined and was 93 (95% CI 87 to 99) for all cancers. There was an excess of leukaemia (SMR 131, 95% CI 97 to 174), restricted to hourly workers (SMR 143, 95% CI 104 to 191). For causes of death other than leukaemia, SMRs were close to or below the null value of 100. Results by work area (process group) were unremarkable for non-Hodgkin's lymphoma, multiple myeloma, and stomach cancer. Maintenance workers had a slight increase in deaths from lung cancer...

Influencia de la microestructura en las propiedades mecánicas y térmicas de mezclas de caucho natural y caucho estireno butadieno; Influence of the microstructure on the mechanical an thermal properties of Natural Rubber and Styrene Butadiene Rubber

Mansilla, Marcela Angela
Fonte: Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires Publicador: Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires
Tipo: info:eu-repo/semantics/doctoralThesis; tesis doctoral; info:eu-repo/semantics/publishedVersion Formato: application/pdf
Publicado em //2012 SPA
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101.14418%
El trabajo de Tesis aquí expuesto representa la investigación de un tema de gran interés tanto científico como tecnológico como es el estudio de mezclas elastoméricas vulcanizadas compuestas por caucho natural NR y caucho estireno butadieno SBR. Se tratan de dos de los elastómeros más utilizados a escala global para distintas aplicaciones industriales, en particular como compuestos en diferentes tipos de neumáticos. Se ha desarrollado una técnica para preparar mezclas a escala de laboratorio utilizando la técnica de disolución en un solvente adecuado de ambos elastómeros, incorporación de curativos, mezclado y posterior evaporación. De esta forma se fabricaron 11 compuestos con diferentes proporciones de NR/SBR. También se utilizaron mezclas similares preparadas en un molino de laboratorio. Justamente la diferencia en el método de mezclado de estas muestras llevó a diferentes comportamientos mecánicos y térmicos, producto de las subestructuras obtenidas. Los compuestos fueron preparados con un sistema de cura basado en azufre y acelerante, y vulcanizados a 160 °C que es una temperatura de interés tecnológico. De esta forma, en función de las distintas composiciones estudiadas se lograron diferentes subestructuras...

Application of Artificial Neural Networks in Predicting Abrasion Resistance of Solution Polymerized Styrene-Butadiene Rubber Based Composites

Li, Hao; Yang, Dazuo; Chen, Fudi; Zhou, Yibing; Xiu, Zhilong
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 21/05/2014
Relevância na Pesquisa
70.12031%
Abrasion resistance of solution polymerized styrene-butadiene rubber (SSBR) based composites is a typical and crucial property in practical applications. Previous studies show that the abrasion resistance can be calculated by the multiple linear regression model. In our study, considering this relationship can also be described into the non-linear conditions, a Multilayer Feed-forward Neural Networks model with 3 nodes (MLFN-3) was successfully established to describe the relationship between the abrasion resistance and other properties, using 23 groups of data, with the RMS error 0.07. Our studies have proved that Artificial Neural Networks (ANN) model can be used to predict the SSBR-based composites, which is an accurate and robust process.