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Euchler, Eric, Radek Stocek, Michael Gehde, Jörg-Michael Bunzel, Wolfgang Saal, and Reinhold Kipscholl. "Fracture behavior of rubber powder modified rubber blends applied for conveying belt top covers." Universitätsbibliothek Chemnitz, 2016. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-qucosa-198136.
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The aim of this study is concentrated on the experimental investigation of wear resistance of rubber powder modified rubber blends. Styrene-Butadiene-Rubber (SBR) blends applied for conveying belt top covers have been modified by ground rubber (rubber powder) based on SBR. We theoretically described the rubber wear mechanism due to loading conditions occurring at conveyor belts in the field, to simulate wear behavior of top cover rubber materials. An own developed testing equipment based on gravimetric determination of mass loss of rubber test specimen was used investigating dynamic wear with respect to fracture properties of top cover materials. Furthermore we investigated fatigue crack growth (FCG) data over a broad range of tearing energy by Tear Analyzer to characterize crack propagation behavior of rubber powder modified rubber blends. Thus, we demonstrate the influence of rubber powder on resistance against occurrence of fracture as well as dynamic wear as a function of the rubber powder content in rubber blends applied for conveying belt top covers.
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Euchler, Eric, Radek Stocek, Michael Gehde, Jörg-Michael Bunzel, Wolfgang Saal, and Reinhold Kipscholl. "Fracture behavior of rubber powder modified rubber blends applied for conveying belt top covers." Technische Universität Chemnitz, 2014. https://monarch.qucosa.de/id/qucosa%3A20409.
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The aim of this study is concentrated on the experimental investigation of wear resistance of rubber powder modified rubber blends. Styrene-Butadiene-Rubber (SBR) blends applied for conveying belt top covers have been modified by ground rubber (rubber powder) based on SBR. We theoretically described the rubber wear mechanism due to loading conditions occurring at conveyor belts in the field, to simulate wear behavior of top cover rubber materials. An own developed testing equipment based on gravimetric determination of mass loss of rubber test specimen was used investigating dynamic wear with respect to fracture properties of top cover materials. Furthermore we investigated fatigue crack growth (FCG) data over a broad range of tearing energy by Tear Analyzer to characterize crack propagation behavior of rubber powder modified rubber blends. Thus, we demonstrate the influence of rubber powder on resistance against occurrence of fracture as well as dynamic wear as a function of the rubber powder content in rubber blends applied for conveying belt top covers.
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Bacigalupo, Lauren N. "Fracture behavior of nano-scale rubber-modified epoxies." Thesis, Lehigh University, 2013. http://pqdtopen.proquest.com/#viewpdf?dispub=3598871.
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The primary focus of the first portion of this study is to compare physical and mechanical properties of a model epoxy that has been toughened with one of three different types of rubber-based modifier: a traditional telechelic oligomer (phase separates into micro-size particles), a core-shell latex particle (preformed nano-scale particles) and a triblock copolymer (self-assembles into nano-scale particles). The effect of modifier content on the physical properties of the matrix was determined using several thermal analysis methods, which provided insight into any inherent alterations of the epoxy matrix. Although the primary objective is to study the role of particle size on the fracture toughness, stiffness and strength were also determined since these properties are often reduced in rubber-toughened epoxies. It was found that since the CSR- and SBM-modified epoxies are composed of less rubber, thermal and mechanical properties of the epoxy were better maintained. In order to better understand the fracture behavior and mechanisms of the three types of rubber particles utilized in this study, extensive microscopy analysis was conducted. Scanning transmission electron microscopy (STEM) was used to quantify the volume fraction of particles, transmission optical microscopy (TOM) was used to determine plastic damage zone size, and scanning electron microscopy (SEM) was used to assess void growth in the plastic zone after fracture. By quantifying these characteristics, it was then possible to model the plastic damage zone size as well as the fracture toughness to elucidate the behavior of the rubber-modified epoxies. It was found that localized shear yielding and matrix void growth are the active toughening mechanisms in all rubber-modified epoxies in this study, however, matrix void growth was more prevalent. The second portion of this study investigated the use of three acrylate-based triblocks and four acrylate-based diblocks to modify a model epoxy system. By varying block lengths and the polarity of the epoxy-miscible blocks, a variety of morphologies were generated (such as spherical micelles, layer particles and worm-like micelles). It was found that in some cases, the epoxy-miscible block did not yield domains substantial enough to facilitate increases in toughness. Overall, the thermal and mechanical properties of the acrylate-based triblock- and diblock-modified epoxies were found to be similar to CTBN-modified epoxy, which was used as a control. However, there were properties that were improved with the acrylate-based diblock-modified epoxies when compared to the acrylate-based triblock modified epoxies. Specifically, the viscosity penalty of the diblock-modified epoxies was shown to be a marked improvement over the triblock-modified epoxies, especially given that the fracture toughness values are similar. This reduction in the viscosity penalty becomes an important criterion when considering processing procedures and applications. Additionally, comparing the morphology of the resulting modified-epoxies utilizing atomic force microscopy (AFM) and scanning electron microscopy (SEM) led to a better understanding of the relationship between the particle morphology obtained and the physical properties of the acrylate-based rubber-modified epoxy systems in this research.
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JARAMILLO, NATALIA ANDREA DURÁN. "MECHANICAL BEHAVIOR OF SOILS REINFORCED WITH TIRES RUBBER." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2016. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=27554@1.
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PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIROCOORDENAÇÃO DE APERFEIÇOAMENTO DO PESSOAL DE ENSINO SUPERIOR
PROGRAMA DE EXCELENCIA ACADEMICA
O volume de pneus inservíveis continua aumentando a cada ano, se tornando um tema de grande preocupação para a sociedade. Motivados por esta problemática ambiental, o presente estudo experimental propõe utilizar a borracha de pneu triturada como reforço de solos, em duas diferentes granulometrias (chips e fibras), como material alternativo para o reforço de dois tipos de solos (areia e solo argiloso). Com este fim realizaram-se ensaios mecânicos, tais como ensaios de compactação proctor standard, ensaios triaxiais do tipo consolidado e isotropicamente drenado e ensaios de adensamento unidimensional, para avaliar os efeitos da granulometria da borracha de pneu, triturada em chips e fibras (com os tamanhos médios de 4,6 mm e 2 mm, respectivamente) e do teor de borracha de pneu (5, 10 por cento e 15 por cento em relação à massa de solo seco), no comportamento mecânico de misturas de areia-borracha e de misturas solo argiloso-borracha. Os resultados mostraram que tanto os chips como as fibras de pneu de borracha contribuem no aumento dos parâmetros de resistência ao cisalhamento de ambos os solos e aumentam a energia de deformação absorvida durante o cisalhamento. Ao analisar a resposta obtida em ambos os solos, se evidencia que, tanto para a argila quanto para a areia, foi mais efetivo o reforço com 10 por cento de fibras de borracha de pneu. Todos os compósitos estudados possuem características de resistência que poderiam cumprir as exigências de determinadas obras geotécnicas (aterros sobre solos moles, reforço de taludes, solo de base de fundações superficiais), portanto o uso da borracha de pneu como reforço de solos contribuiria com o menor consumo de material natural e redução dos custos de transporte e volume de material mobilizado.
The volume of discarded tires continues to increase each year, becoming a major topic of concern for society. Motivated by this environmental issue, this experimental study proposes using tire chips and tire buffings as an alternative material to improve the shear strength of two types of soil (sand and clayey soil). Because of this, standard Proctor compaction tests, consolidated-drained triaxial tests and compressibility tests were performed to assess the influence of tire rubber particle size, (with average sizes of 4.6 mm and 2 mm, respectively) and tire rubber content (5, 10 percent and 15 percent by dry weight of soil) into the mechanical behavior of sand and clayey soil. The tests results showed that both, chips and buffings contribute increasing the shear strength parameters of both the soil and increase the strain energy absorbed during the shear phase. By analyzing, the mechanical response both for clayey soil and for sand was found that the best shear strength improvement was obtained at 10 percent of tire buffings. All the composites showed resistance characteristics that would ensure the requirements for many geotechnical applications (embankments over soft soils, slope reinforcement and surface foundations), so the use of waste tires as a reinforcement material would help solve problems associated with natural resources and reducing transportation costs and earthmoving.
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Euchler, Eric, Gert Heinrich, Hannes Michael, Michael Gehde, Radek Stocek, Ondrej Kratina, Reinhold Kipscholl, Jörg-Michael Bunzel, and Wolfgang Saal. "Fundamental studies on dynamic wear behavior of SBR rubber compounds modified by SBR rubber powder." Universitätsbibliothek Chemnitz, 2016. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-qucosa-198870.
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The aim of this study is focused on the experimental investigation of dynamic wear behavior of carbon black filled rubber compounds comprising pristine styrene butadiene rubber (SBR) together with incorporated SBR ground rubber (rubber powder). We also analyzed and described quantitatively the service conditions of some dynamically loaded rubber products, which are liable to wear (e.g. conveyor belts, tires). Beside the well-known standard test method to characterize wear resistance at steady-state conditions, we used an own developed testing equipment based on gravimetric determination of mass loss of rubber test specimen to investigate the influence of rubber powder content on dynamic wear depending on varying impact energy levels. Incorporation of SBR rubber powder in SBR rubber compounds increases wear. With increasing rubber powder content the wear at steady-state conditions progressively increases. However, the level of wear at dynamic loading conditions increases only once, but stays constant subsequently even with contents of incorporated rubber powder.
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Euchler, Eric, Gert Heinrich, Hannes Michael, Michael Gehde, Radek Stocek, Ondrej Kratina, Reinhold Kipscholl, Jörg-Michael Bunzel, and Wolfgang Saal. "Fundamental studies on dynamic wear behavior of SBR rubber compounds modified by SBR rubber powder." Deutsche Kautschuk-Gesellschaft e.V, 2015. https://monarch.qucosa.de/id/qucosa%3A20419.
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The aim of this study is focused on the experimental investigation of dynamic wear behavior of carbon black filled rubber compounds comprising pristine styrene butadiene rubber (SBR) together with incorporated SBR ground rubber (rubber powder). We also analyzed and described quantitatively the service conditions of some dynamically loaded rubber products, which are liable to wear (e.g. conveyor belts, tires). Beside the well-known standard test method to characterize wear resistance at steady-state conditions, we used an own developed testing equipment based on gravimetric determination of mass loss of rubber test specimen to investigate the influence of rubber powder content on dynamic wear depending on varying impact energy levels. Incorporation of SBR rubber powder in SBR rubber compounds increases wear. With increasing rubber powder content the wear at steady-state conditions progressively increases. However, the level of wear at dynamic loading conditions increases only once, but stays constant subsequently even with contents of incorporated rubber powder.
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Suttipong, Angthong. "Role of the Rubber Cooperatives in Thailand in Improving Smallholders' Incomes: Empirical Study in Traditional and Non-traditional Rubber Production Areas." Doctoral thesis, Kyoto University, 2021. http://hdl.handle.net/2433/263768.
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RIBEIRO, PHILLIPE MOURAO. "MECHANICAL BEHAVIOR OF BENTONITE REINFORCED WITH GROUND RUBBER AND PET FLAKES." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2018. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=36542@1.
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PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIROCOORDENAÇÃO DE APERFEIÇOAMENTO DO PESSOAL DE ENSINO SUPERIOR
PROGRAMA DE EXCELENCIA ACADEMICA
As atuais técnicas propostas para a destinação final dos pneus não são 100 por cento eficientes, existindo um grande déficit do material em questão. Um outro material que necessita de uma destinação final é o PET (polietileno tereftalato), que hoje em dia, apesar da grande quantidade reciclada, necessita de mais opções de destinação. O estudo apresentado propõe a utilização da borracha triturada (em forma de fibras e em pó - granulometria inferior a 2mm) em diferentes teores (de 5 por cento e 10 por cento, em relação ao peso seco da bentonita) e do PET triturado (na forma de fibras e em pó), como reforço de uma bentonita, para aumento dos parâmetros de resistência desta. O objetivo da pesquisa consiste em avaliar a possibilidade da utilização da borracha e do PET como melhoramento de bentonita em obras geotécnicas, como por exemplo em camadas impermeabilizantes para aterros sanitários, visto que com a utilização da borracha e do PET em obras geotécnicas seria possível a destinação de um grande volume desses materiais. Para o desenvolvimento do estudo experimental foram realizados ensaios de caracterização física e de caracterização mecânica, como ensaios de cisalhamento direto e adensamento. Com resultados obtidos a partir dos ensaios de cisalhamento direto e ensaio de adensamento, pode se perceber que as misturas B90BF10 e B90PETT10 se mostraram mais favoráveis a utilização como barreira impermeabilizando para aterros sanitários, tendo em vista o aumento nas resistências de Pico, pós pico e residual, além do aumento do coeficiente de adensamento (cv) e redução da permeabilidade (k).
The current techniques proposed for the final destination of the tires are not 100 percent efficient, and there is a great deficit of the material in question. Another material that needs an end destination is the PET (polyethylene terephthalate), which nowadays, despite the large amount recycled, needs more disposal options. the present study proposes the use of crushed rubber (in the form of fibers and powder - granulometry of less than 2 mm) in different contents (5 percent and 10 percent, in relation to the dry weight of bentonite) and crushed PET (in the form of fibers and powder), as reinforcement of a bentonite, to increase the resistance parameters of this one. The objective of the research is to evaluate the possibility of using rubber and PET as an improvement of bentonite in geotechnical works, such as waterproofing layers for sanitary landfills, since with the use of rubber and PET in geotechnical works it would be possible to allocate a large volume of these materials. For the development of the experimental study, physical characterization and mechanical characterization tests were performed, such as direct shear tests and densification. With results obtained from the direct shear tests and the densification test, it can be seen that the mixtures B90BF10 and B90PETT10 were more favorable to use as a waterproofing barrier for sanitary landfills, in view of the increase in peak and residual, besides the increase of the coefficient of densification (cv) and reduction of the permeability (k).
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Warley, Russell Lee. "Silica-silicone interactions: Non-linear viscoelastic behavior of silica-filled silicone rubber." Case Western Reserve University School of Graduate Studies / OhioLINK, 1993. http://rave.ohiolink.edu/etdc/view?acc_num=case1057089336.
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Broussard, Dylan W. "Cyclic Behavior of Small Scale Shear Panels Containing Fiber Reinforced Rubber Concrete." Thesis, University of Louisiana at Lafayette, 2016. http://pqdtopen.proquest.com/#viewpdf?dispub=10002460.
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Shear beams and shear walls were constructed using varying amounts of steel fibers and rubber to determine the effect of these constituents on concrete when subject to shear loads and reversed cyclic loadings. 22 concrete beams were tested using mixes with differing amounts of fibers and rubber. The beams were designed to fail in shear by applying a single downward point load at midspan using a MTS Universal Testing Machine. Using the recorded load and displacement data the behavior of each beam and the shear strength contribution for each mix were determined. For all mixes that included fibers and/or rubber the shear strengths increased 12% to 56% in comparison to the plain concrete mixes. Four concrete walls were also tested using four of the 22 beam mixes. The four selected mixes were chosen based on the comparable compressive strengths and mix constituents. The walls were designed to fail in shear by applying a lateral load to a top block cast on top of the shear wall. The walls were tested on a modular strong-block test system within a rigid steel frame so that the load could be applied by a hydraulic actuator. During testing, the displacement at 10 selected locations, the loads placed on the walls at each displacement, and the behavior were recorded and analyzed. The walls containing rubber experienced lower strengths, a brittle failure with severe spalling and damage, and dissipated a low amount of energy. The walls containing fibers exhibited strain hardening characteristics leading to a ductile failure mode, higher strengths, and little web damage. Using the findings from this study, it can be concluded that both fibers and rubber can be used to increase shear strength but only fibers were found to be a viable option for application in walls subject to reverse cyclic loadings.
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Pole, Sandeep. "Constitutive Modeling of the Rheological Behavior of Rubber Compounds and Plastic Composites." University of Akron / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=akron155567239888512.
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Ohlemacher, Crittenden John. "Double Network Formation During Aging of a Natural Rubber Vulcanizate." University of Akron / OhioLINK, 2005. http://rave.ohiolink.edu/etdc/view?acc_num=akron1132327518.
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Sujarwo, Rakhma [Verfasser]. "Palm Oil and Rubber Price and Trader’s Behavior at International towards Local Level / Rakhma Sujarwo." Göttingen : Niedersächsische Staats- und Universitätsbibliothek Göttingen, 2021. http://d-nb.info/1235757137/34.
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ITOH, Yoshito, Haosheng GU, Kazuya SATOH, Yukihiro KUTSUNA, 義人 伊藤, 浩声 顧, 和也 佐藤, and 幸浩 忽那. "EXPERIMENTAL INVESTIGATION ON AGEING BEHAVIORS OF RUBBERS USED FOR BRIDGE BEARINGS." 土木学会, 2006. http://hdl.handle.net/2237/8622.
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Musigamart, Natedao. "Study of the role of lipids from maturated coagula from Hevea brasiliensis latex on natural rubber behavior in oxidative conditions." Thesis, Montpellier, SupAgro, 2015. http://www.theses.fr/2015NSAM0004/document.
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Le caoutchouc naturel (CN), un produit dérivé du latex d'Hevea brasiliensis, est connu pour ses propriétés mécaniques supérieures pour certaines à celles de ses concurrents synthétiques. Néanmoins, le haut degré d'insaturation du poly(cis-1,4-isoprene) le rend susceptible à la thermo-oxydation. Heureusement, le CN est doté de composés non-isoprènes dont certains ont des propriétés antioxydantes. Les lipides sont les plus importants non-isoprènes retenus dans le caoutchouc et contiennent des molécules à activité antioxydante en particulier les tocotriènols. Il est connu que durant la maturation de coagula de latex, la composition chimique et les propriétés du caoutchouc obtenu sont altérées, mais les mécanismes complexes de cette altération ne sont pas encore complètement élucidés. Dans cette étude, l'évolution de certaines molécules antioxydantes natives pendant la maturation a été suivie en relation avec certaines propriétés physiques du caoutchouc. Deux expérimentations de maturation ont été mises en œuvre. La première mettait en jeu des conditions non contrôlées de maturation suivies d'un procédé de confection du caoutchouc basé sur celui des feuilles fumées (RSS) ou non (USS). La seconde a été conduite dans un dispositif expérimental dédié permettant le contrôle des facteurs de l'environnement tels que l'humidité relative, la température et la concentration en oxygène. Le procédé de confection du caoutchouc était dans ce cas basé sur celui des caoutchoucs spécifiés techniquement (TSR). L'évolution des échantillons pendant la maturation a été étudiée à différentes échelles : propriétés en masse (P0, P30 et PRI), mésostructure (% gel, Mw and Mn) et composition biochimique (lipides). En parallèle, l'activité antioxydante in vitro des extraits lipidiques correspondants a été mesurée en utilisant une méthode DPPH optimisée. La quantité et la qualité des lipides extraits évoluent pendant la maturation, en particulier en aérobiose. La quantité totale de lipides décroit, avec, en début de maturation, une libération d'acides gras dont la quantité diminue ensuite, avec une disparation des espèces insaturées en premier. La quantité de γ-tocotrienol libres extraits change peu au cours de la maturation alors que sa forme estérifiée montre un enrichissement en acides gras saturés. L'activité antioxydante de l'extrait lipidique mesurée in vitro est corrélée avec la concentration de γ-tocotrienol libre mais pas avec les valeurs de P30 et PRI qui estiment la résistance du caoutchouc à la thermo-oxydation. Cette absence de corrélation pourrait être due à la différence des conditions de mesure in-vitro de celles existantes au sein du matériau caoutchouc. La localisation des antioxydants dans le caoutchouc et en particulier leur possibilité physique d'interagir avec les doubles liaisons du poly(cis-1,4-isoprene) ou avec des espèces oxydantes reste à étudier afin de comprendre ce qui régit la chute de P30 au cours de la maturation. Des lipides non extractibles ou des molécules non-isoprènes plus polaires (protéines, polyphénols, …) pourraient également influencer la résistance du caoutchouc à la thermo-oxydationNatural rubber (NR), a derived product from H. brasiliensis latex, is known for its high mechanical properties that are, for some, superior to those of its synthetic counterparts. However, the high degree of unsaturation of poly(cis-1,4-isoprene) makes it susceptible to thermo-oxidation. Fortunately, NR is endowed with non-isoprene components of which some have antioxidant properties. Especially, lipids, the main non-isoprene component retained in NR, have been reported to contain antioxidant substances, especially tocotrienols. It is well known that during the maturation of latex coagula, both NR physical properties and chemical composition are altered, but the complex mechanisms of this alteration are still to be elucidated. In the present work, the evolution of some native antioxidant molecules during maturation was followed in relation with some physical properties. Two experimental conditions of maturation were chosen. The first experiment involved uncontrolled conditions based on traditional unsmoked (USS) or ribbed smoked sheet (RSS) processing, while the second was performed in a dedicated maturation device with full control of environmental factors (relative humidity, temperature and oxygen content) followed by a processing based on that of Technically Specified Rubber (TSR). The evolution of samples during maturation was studied at different scales: bulk properties (P0, P30 and PRI), mesostructure (% gel content, Mw and Mn) and biochemical composition (lipids components). In parallel, in vitro antioxidant activity of NR lipid extracts was also investigated using an optimized DPPH method. Lipid quantity and quality evolved during maturation, especially under aerobic conditions. The total amount of lipid extract decreased, with a release of free fatty acids at early stage of maturation followed by a later decrease, unsaturated fatty acids being the first to disappear. The amount of extractable free γ-tocotrienol did not change much during maturation, while its esterified form was enriched in saturated fatty acids. The antioxidant activity measured in vitro correlated well with free γ-tocotrienol concentration but not with the resistance of rubber to thermo-oxidation assessed by P30 or PRI. Indeed, the in vitro conditions of measurement were far from those occurring inside rubber material. The localization of antioxidants in rubber and especially their physical possibility to interact with the double bonds of poly(cis-1,4-isoprene) or with oxidant species should be further investigated to understand what drives the drop of P30 along maturation time. Non extractable lipids or more polar non-isoprene molecular species (proteins, polyphenols, etc…) could also influence the resistance to thermo-oxidation
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TESSARI, CIRO LOYOLA. "ANALYSIS OF THE CEMENT-TREATED AGGREGATE BASE MATERIAL BEHAVIOR WITH A TIRE RUBBER ADDITION FOR PAVEMENTS BASE APPLICATIONS." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2017. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=33692@1.
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PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIROCOORDENAÇÃO DE APERFEIÇOAMENTO DO PESSOAL DE ENSINO SUPERIOR
PROGRAMA DE EXCELENCIA ACADEMICA
Este trabalho apresenta um estudo técnico experimental sobre a utilização de borracha moída de pneu (BMP) como adição, juntamente com cimento Portland à brita graduada simples (BGS), no intuito de avaliar a aplicabilidade desse material em camadas de base de pavimentos rodoviários. Como resultado obtémse uma BGTC - Brita graduada tratada com cimento, com adição de BMP. O principal objetivo da adição de borracha na BGTC é reduzir o fissuramento, que é um problema comum em bases cimentadas. Para melhor comparação dos resultados das misturas com adições de borracha foi realizada uma mistura de BGTC sem adições, a qual foi tratada como mistura padrão neste estudo, com 3 por cento, 4 por cento e 5 por cento de cimento. O agregado granítico selecionado para esta pesquisa é proveniente de jazida situada no município de Cariacica/ES e foi escolhido por ter apresentado bom desempenho nos ensaios de caracterização. A partir da análise granulométrica realizada na borracha, selecionou-se para esse estudo a fração passante na peneira de 2,38mm e retida na peneira de 1,19 mm. Foram estuadas as seguintes porcentagens de adição de BMP: 0,5 por cento, 1,0 por cento, 1,5 por cento, 2,5 por cento, 3,5 por cento e 4,5 por cento. As amostras foram submetidas a ensaios de compactação, compressão simples, compressão diametral, triaxial de cargas repetidas e microscopia eletrônica de varredura. Os ensaios de compressão simples foram realizados com tempos de cura de 7, 28 e 56 dias. Os ensaios de compressão diametral foram realizados com tempos de cura de 28 e 56 dias. Os ensaios triaxiais de carga repetida foram realizados com tempo de cura de 56 dias. Os resultados obtidos foram satisfatórios, sendo dependentes do teor de BMP utilizados e do tempo de cura. Dentre as composições de BMP estudadas, a que apresentou o melhor comportamento foi a que possuia adição de 1,5 por cento de borracha e 56 dias de cura. Esta adição apesar de reduzir a RCS e a RTCD em 30 por cento e 28 por cento respectivamente, proporcionou melhoria no comportamento resiliente e menor perda de resistência na região pós pico perante o ensaio de RCS. Tal fato ressalta o emprego positivo de borracha de pneu triturada em camadas de base de pavimentos rodoviários, tanto sob a ótica da engenharia de pavimentos quanto em relação a questões ambientais e econômicas.
This work presents a technical and experimental study on the use of tire rubber as an addition, together with Portland cement, to a simple graded gravel, in order to evaluate the applicability of this material in the base layers of road pavements. As a result, cement-treated graded gravel with the addition of rubber is obtained. The main objective of the addition of rubber is to reduce cracking, which is a common problem in cemented bases. A standard mixture of cement-treated graded gravel was carried out for better comparison between the mixtures with additions of 3 percent, 4 percent and 5 percent of cement. The granitic aggregate selected for this research came from the municipality of Cariacica/ES and was selected because it presented an appropriate performance in the characterization tests. From the granulometric analysis performed on this material, the fraction passing the sieve 2,38 mm and retained in the sieve 1,19 mm, was selected for this study. In this study were selected 0,5 percent, 1,0 percent, 1,5 percent, 2,5 percent, 3,5 percent and 4,5 percent additions of rubber. The blends were subjected to compaction, direct compression, split tensile, cyclic triaxial and scanning electron microscope tests. Direct compression tests were performed with cure times of 7, 28 and 56 days. Split tensile tests were performed with curing time of 28 and 56 days. Cyclic triaxial tests were performed with curing time os 56 days. The results were satisfactory, being dependent on the content of rubber and the curing time. Among the blends that were analyzed, 1,5 percent of addition and 56 days of curing time leaded to the best results. Despite the reduction of 30 percent and 28 percent in the compression and tensile resistances, this amount of rubber addition provided a better resilient behavior and a higher post pick resistance in the compression test. This fact highlights the positive use of tire rubber in pavement base layers, not only from the standpoint of pavement engineering, but promoting gains of sustainability and economy as well.
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Mousa, A., G. Heinrich, and U. Wagenknecht. "Thermal properties of carboxylated nitrile rubber/nylon-12 composites-filled lignocellulose materials." Sage, 2014. https://tud.qucosa.de/id/qucosa%3A35546.
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Organic hybrid composites based on carboxylated nitrile rubber and nylon-12 reinforced with mercerized and diisocyanated lignocellulose residue (LCR) was prepared. The influence of the LCR on the viscoelastic properties of these organic hybrids was investigated by dynamic mechanical analysis and thermal analysis (differential scanning calorimetry (DSC)). It is found that either the position of the damping peak was shifted to higher values or the intensity of the damping peak was significantly increased with LCR. These results could imply that the LCR enhanced the damping properties of the composites. The thermal stability of the composites was evaluated with the mean values obtained using thermogravimetrical analysis. The decomposition rate was investigated using differential thermal gravimetry. The crystallization behavior of the prepared composites was checked by DSC.
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Ivanoska-Dacikj, Aleksandra, Gordana Bogoeva-Gaceva, René Jurk, Sven Wießner, and Gert Heinrich. "Assessment of the dynamic behavior of a new generation of complex natural rubber-based systems intended for seismic base isolation." Sage, 2017. https://tud.qucosa.de/id/qucosa%3A35604.
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This work, conceived as a second step in the development of high-performance damping materials suitable for seismic application, describes the preparation and characterization of complex natural rubber-based composites containing hybrid nano- and conventional fillers. The cluster–cluster aggregation model was used to assess the apparent filler networking energy. The values obtained suggested that the presence of the hybrid nanofiller strengthens the filler networking. The same model was used to understand the mechanisms of energy dissipation. The damping coefficient was found to be in the sought range between 10% and 20% (at 0.5 Hz and high shear strain).
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Jin, Min. "Determination of fracture mechanics behavior of polyethylene sheets." Thesis, Linnéuniversitetet, Institutionen för maskinteknik (MT), 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:lnu:diva-65706.
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Polyethylene is a widely-used material in package industries. The fracture behavior of this material has not been studied in the plastic region in many years. In this thesis work, the J-Integral which is one material property used to represent the plastic material strength is calculated through the numerical analysis. To build a correct numerical model, the material behavior is summarized from previous uniaxial tensile test. The result from the fracture experiment for variable initial crack length is used to validate the reliability of the numerical model. The numerical analysis is done by the software ABAQUS which has the function to get the value of J-Integral directly. The final result contains the comparison between experiments and numerical analysis and the value of J-Integral at the crack initiation.
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Craig, McKinzie King Kimi Lynn. "Rubber stamps and litmus tests the president, the senate, and judicial voting behavior in abortion cases in the U.S. federal district courts /." [Denton, Tex.] : University of North Texas, 2007. http://digital.library.unt.edu/permalink/meta-dc-3985.
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Craig, McKinzie. "Rubber Stamps and Litmus Tests: The President, the Senate, and Judicial Voting Behavior in Abortion Cases in the U.S. Federal District Courts." Thesis, University of North Texas, 2007. https://digital.library.unt.edu/ark:/67531/metadc3985/.
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This thesis focuses on how well indicators of judicial ideology and institutional constraints predict whether a judge will vote to increase abortion access. I develop a model that evaluates a judge's decision in an abortion case in light of ideological factors measured at the time of a judge's nomination to the bench and legal and institutional constraints at the time a judge decides a case. I analyze abortion cases from all of the U.S. Federal District Courts from 1973-2004. Unlike previous studies, which demonstrate that the president and the home state senators are the best predictors of judicial ideology, I find that the Senate Judiciary Committee at the time of the judge's nomination is the only statistically significant ideological indicator. Also, contrary to conventional wisdom, Supreme Court precedent (a legal constraint) is also a significant predictor of judicial voting behavior in abortion cases.
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Subramani, Bhagavatheswaran Eshwaran [Verfasser], Gert [Gutachter] Heinrich, and Jyrki [Gutachter] Vuorinen. "Exploring the Piezoresistive Characteristics of Solution Styrene Butadiene Rubber composites under static and Dynamic Conditions - A Novel Route to Visualize Filler Network Behavior in Rubbers / Eshwaran Subramani Bhagavatheswaran ; Gutachter: Gert Heinrich, Jyrki Vuorinen." Dresden : Technische Universität Dresden, 2019. http://d-nb.info/1226899161/34.
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Merckel, Yannick. "Experimental characterization and modeling of the mechanical behavior of filled rubbers under cyclic loading conditions." Phd thesis, Ecole Centrale de Lille, 2012. http://tel.archives-ouvertes.fr/tel-00736624.
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Rubber-like materials are submitted to cyclic loading conditions in various applications. Fillers are always incorporated within rubber compounds. They improve the mechanical properties but induce a significant stress-softening under cyclic loadings. The physical source of the softening is not yet established and its modeling remains a challenge. For a better understanding of the softening, filled rubbers are submitted to cyclic loadings. In order to quantify the effects of the loading intensity and the number of cycles, original methods are proposed to characterize the softening. To study the influence of the material microstructure on the softening, compounds with various compositions are considered.Non proportional tensile tests including uniaxial and biaxial loading paths are applied in order to highlight the softening induced anisotropy. Such unconventional experimental data are used to provide a general criterion for the softening activation. A constitutive modeling grounded on a thorough analysis of experimental data is proposed. The model is based on a directional approach. The Mullins softening is accounted for by the strain amplification concept and is activated by a directional criterion. The model ability to predict non proportional softened material responses is demonstrated
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Ali, Mahdi. "Study of the bitumen aging effects on the rheological properties and fatigue behavior." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2018. http://amslaurea.unibo.it/16255/.
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A study of bitumen aging effects on the rheological properties and fatigue behavior is carried out on five polymer modified bitumen provided by an oil company. Dynamic Shear Rheometer (DSR), is used to perform advanced experimental investigation. It allows practicing frequency sweep tests, fatigue tests and time sweep tests. Polymer modified bitumen with different percentage of SBS with or without the presence of crumb rubber are tested before and after short and long aging processes.
Master curves were generated based on frequency sweep tests data, they are studied, and a comparison was conducted between each bitumen before and after aging. In this thesis, the DSR is presented, as well as the testing procedure and the tested materials. A fatigue life analysis of the results, based on the use of two different criteria, the first criterion is classically used: it consists in defining the failure as a 50% loss of the initial stiffness. The other criteria based on dissipated energy data.
This thesis provides results which show the effects of several factors on fatigue and healing response such as bitumen type, ageing, the presence of rubber and polymer modification.
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Abebe, Abay Damte, and Qikang He. "Foam Behavior Analysis Based On A Force Measurement System." Thesis, Högskolan i Halmstad, Akademin för ekonomi, teknik och naturvetenskap, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:hh:diva-37250.
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Abstract In the world where every sector of industrial manufacturing is being converted toautomated systems, surface finishing processes like sanding and polishing seem to lag.This phenomenon is not surprising as these processes are complex to optimize. Therehave been projects going on with the support of European Commission to findsolutions under SYMPLEXITY (Symbiotic Human-Robot Solutions for ComplexSurface Finishing Operations). One of the projects in under this include poliMATIC(Automated Polishing for the European Tooling Industry). Halmstad University isinvolved in doing projects. This project took a portion of this study in aim to understand a foam material’s behavior used for sanding tool at the tip of a robotic arm. This is studied using a forcemeasurement system developed at Halmstad University. The project has two sectionsand starts with one; Understanding the force measurement system and upgrading innecessary ways. Two; studying how the foam material compressive hardness propertyis affected when the material is fit with sandpaper for sanding operation using theforce measurement system. The study finally revealed how the combination of thefoam with sandpaper affects the robustness of the material, and significantlyimproved the output of the system with by reducing the noise level with 40%.
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Ozdemir, Gokhan. "Response Of Isolated Structures Under Bi-directional Excitations Of Near-field Ground Motions." Phd thesis, METU, 2010. http://etd.lib.metu.edu.tr/upload/3/12612039/index.pdf.
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Simplified methods of analysis described in codes and specifications for
seismically isolated structures are always used either directly in special cases or for
checking the results of nonlinear response history analysis (RHA). Important
predictions for seismically isolated structures by simplified methods are the
maximum displacements and base shears of the isolation system. In this study, the
maximum isolator displacements and base shears determined by nonlinear RHA are
compared with those determined by the equivalent lateral force (ELF) procedure in
order to assess the accuracy of the simplified method in the case of bi-directional
excitations with near-field characteristics. However, although there are currently
many methods for ground motion selection and scaling, little guidance is available
to classify which method is more appropriate than the others in any applications.
Features of this study are that the ground motions used in analysis are selected and
scaled using contemporary concepts and that the ground excitation is considered biv
directional. The variations in response of isolated structures due to application of
ground motions uni-directionally and bi-directionally are also studied by employing
a scaling procedure that is appropriate for the bi-directional analysis. The proposed
new scaling methodology is an amplitude scaling method that is capable of
preserving the horizontal orthogonal components and it is developed especially for
dynamic analysis of isolated structures. Analyses are conducted for two different
symmetric reinforced concrete isolated structure for two different soil conditions in
structural analysis program SAP2000. Effect of asymmetry in superstructure on
isolator displacement is also investigated with further analyses considering 5% mass
eccentricity at each floor level. Furthermore, once the significance of the orthogonal
horizontal component on the response of isolation system is shown, the biaxial
interaction of hysteretic behavior of lead rubber bearings is implemented in
OpenSees by developing a subroutine which was not readily available.
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Pagoto, Leticia Martelo. "Estudo do comportamento à água em argamassas de revestimento incorporadas com borracha de pneus /." Ilha Solteira, 2018. http://hdl.handle.net/11449/180293.
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Orientador: Cesar Fabiano FioritiResumo: A evolução do processo de industrialização vem desencadeando um consumo desenfreado dos recursos naturais. Diante do exposto, a indústria automobilística contribui em grande escala para a geração de resíduos de pneus, os quais ao serem descartados inadequadamente causam inconvenientes ambientais e de saúde pública. Paralelamente, a borracha proveniente do processo mecânico de recauchutagem de pneus vem sendo utilizada em pesquisas relacionadas ao estudo de variadas propriedades em compósitos cimentícios. Perante isso, este trabalho realizou uma avaliação experimental do comportamento à água de argamassas mistas de revestimento produzidas com a incorporação de duas diferentes granulometrias de borracha de pneus, estudadas segundo a vertente da substituição parcial da areia. O teor de incorporação de borracha de pneus nas argamassas foi de 5%, 10%, 15% e 20%, em volume. As diferentes granulometrias de borracha, provenientes da recauchutagem de pneus, foram doravante denominadas de grossa (passante na peneira #1,19 mm) e fina (passante na peneira #0,60 mm). O programa experimental contou com a execução de ensaios de densidade de massa aparente, retenção de água e índice de consistência nos compósitos no estado fresco; posteriormente, com os compósitos no estado endurecido, foram executados os ensaios de densidade de massa aparente, absorção de água por capilaridade, ensaio de secagem, absorção de água por imersão, permeabilidade ao vapor de água e permeabilidade à água sob press... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: The evolution of the industrialization process has triggered an uncontrolled consumption of natural resources. According to this fact, the automobile industry contributes greatly in generation of waste tires, which, with improper disposal, may cause environmental and public health inconveniences. In parallel, the rubber from the mechanical process of tire retreading has been used in researches related to the study of various properties in cement composites. According to it, this work purposed to carry out an experimental evaluation of the behavior to the water of mixed covering mortars produced with the incorporation of two different grades of tire rubber, studied according to the scope of partial sand replacement. The content of tire rubber incorporation in the mortars was 5%, 10%, 15% and 20% by volume. The different grades of rubber from tire retreading were henceforth referred to as thick (passing through the # 1.19 mm sieve) and fine (passing through the # 0.60 mm sieve). The experimental program consisted in the execution of bulk density tests, tests of water retention and consistency index in the fresh state; subsequently, with the composites in the hardened state, bulk density tests, capillary water absorption tests, drying tests, tests of water absorption by immersion, water vapor permeability and water permeability under pressure. The results showed that the incorporation of rubber could contribute positively in most of the studied properties. Thus, among the gradin... (Complete abstract click electronic access below)
Mestre
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Bates, Griffin Michael. "Characterizing the Cold Temperature Performance of Guayule (Pathenium argetnatum) Natural Rubber and Improving Processing of Guayule and Agronomic Practices of Taraxacum kok-saghyz." The Ohio State University, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=osu1448376403.
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Gough, Julia. "Stress-strain behaviour of rubber." Thesis, Queen Mary, University of London, 2000. http://qmro.qmul.ac.uk/xmlui/handle/123456789/28819.
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Several aspects of the stress-strain behaviour of rubber, important for evaluating its properties for finite element analysis and engineering applications, are investigated. Measurements of the deformation behaviour of an elastomer containing a compressible filler are used to assess theoretical equations for the compression modulus of rubber pads bonded to rigid endplates. The volume fraction of filler is estimated from a simple model. The first cycle stress-strain behaviour of filled and unfilled rubbers is characterised from uniaxial tests and by measuring both non-zero principal stresses with a novel pure shear technique. Various theoretical forms for the strain energy density function are assessed. The results support the assumption that the strain energy of filled natural rubber is a function only of the first strain invariant. Finite element modelling of the behaviour of a hyperelastic material in simple shear reveals that the proximity of the free edges in conventional simple shear testpieces strongly influences the stresses and deflections in the thickness direction. These finding are qualitatively supported by experiment. The effect of free edges on the shear modulus is also assessed. Deviations from hyperelastic behaviour are investigated through experimental studies of stress relaxation, cyclic stress softening and the superposition of a torsion on a uniaxial extension. Anisotropic deformations can result in corresponding differences in the amounts of stress relaxation or stress softening in different directions. Isotropic models cannot model these features but may be adequate for most practical applications. The relationship between the modulus and crystallinity of partially crystalline rubber is determined experimentally. The reinforcing effect of the crystals is found to be approximately independent of their morphology and of the modulus of the amorphous rubber. Studies of yielding of partially crystalline rubber show that the yield stress increases with increasing amounts of crystallization whereas the yield strain remains roughly constant.
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Rush, Jeremy Richard. "Crystal growth, guest ordering and ferroelastic properties of urea inclusion compounds." Diss., Manhattan, Kan. : Kansas State University, 2007. http://hdl.handle.net/2097/526.
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Higgins, Daniel. "Frictional behaviour of rubber on ice." Thesis, University of Edinburgh, 2007. http://hdl.handle.net/1842/14063.
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A study of the friction between styrene butadiene rubber and ice has been undertaken. The instrument used o perform the measurements (a tribometer) was designed, constructed and developed specifically for this task and so has been optimised for this tribosystem. The versatile and compact design is easily accommodated in a domestic freezer and has been utilised to measure friction in both steady-state and transient regimes. The experimental component of the study is comprised of two separate and novel parts. Firstly, steady-state (constant temperature, load and speed) measurements of the sliding friction are placed on a friction map in speed-temperature space. This enables the frictional behaviour of this complex system to be presented in a clear and uncomplicated fashion. As the frictional behaviour of both rubber and ice independently change with the prevalent environmental conditions, presentation of data in this format allows the changes to be observed for all conditions encompassed by the map. Reference to maps of this form is beneficial from both traction and sliding perspectives as the areas of high and low friction are clearly demonstrated. The second experimental section relates to the transient nature of friction as it changes from static to sliding regimes. This study uncovered the temperature and force rate dependencies that can be utilised to increase the (typically) very low friction on ice. Application of this aspect of rubber-ice friction is particularly important to the automotive industry where transient regimes are widely used in safety and performance enhancement systems such as anti-lock braking systems and stability control.
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Wu, Guangchang. "The mechanisms of rubber abrasion." Thesis, Queen Mary, University of London, 2017. http://qmro.qmul.ac.uk/xmlui/handle/123456789/25986.
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Rubber abrasion is one of the most important properties for rubber products, such as tyres. However, due to its complexity rubber abrasion is still a very challenging topic in rubber research. Rubber abrasion is not governed by a single mechanism. Different mechanisms can dominate the abrasion behaviour depending on the rubber compound, base polymer type, loading severity, contact conditions, testing temperature and chemical environment. This study investigates the different mechanisms for rubber abrasion and the transition between these mechanisms using two types of abrasion apparatus, a blade abrader and a surface abrader, respectively. Blade abrasion was used to generate the abrasion pattern. Once the abrasion pattern was formed on the rubber surface under unidirectional sliding, the underlying mechanism was primarily one of fatigue crack growth, which is referred as "fatigue wear" in the literature. An independent pure shear fatigue test with various loading profiles was conducted to predict the crack growth rate using a fracture mechanics approach during these abrasion tests. The tearing energy during blade abrasion was calculated using a fracture mechanics approach. A Finite Element Analysis (FEA) technique using the Virtual Crack Closure Technique (VCCT) was adopted. The VCCT approach was a simpler, faster and more reliable approach to derive the tearing energy under these complicated large strain contact conditions. The prediction of the abrasion rate using this independent measurement of the crack growth resistance of materials worked best for unfilled SBR material. A bespoke surface contact abrasion machine was used to investigate rubber abrasion on silicon carbide sandpaper under both dry and wet conditions. Depending on the materials, contact conditions and sliding velocity, two different mechanisms were observed. The first being a mechanochemical degradation, during which a sticky layer was generated on the rubber surface. This behaviour is also called "smearing wear". The second failure mode resulted from a purely mechanical fracture named "abrasive wear". It seemed that the carbon black filled rubber was more susceptible to smearing wear than the silica filled one. Higher sliding velocities promoted smearing wear, possibly due to higher temperatures being generated at the interface. Alternatively, water lubrication was seen to promote abrasive wear. Therefore, the abrasion mechanism changed to more rapid abrasive wear under wet conditions, which resulted in a significant increase in the rate of weight loss. Finally, the sticky debris generated during the smearing wear was characterised using various different techniques. This revealed that the sticky debris had more oxygen and lower carbon and sulphur content. It contained a greater amount volatiles and generated more char formation during its degradation in the air. The molecular weight of the sticky debris was much lower when compared to the original uncured rubber. It seemed that in the sticky debris the filler network can slowly recover and the degraded polymer chains can re-absorb back onto filler surface forming "bound rubber", which leads to faster rates of weight loss.
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Canevarolo, Sebastiao V. "Melt behaviour of thermoplastic rubbers." Thesis, Loughborough University, 1986. https://dspace.lboro.ac.uk/2134/27871.
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Thermoplastic rubbers have been shown to have unusual solid state properties which must derive from the structure of the melt prior to solidification. The melt phase has been studied in some detail. The molecular architecture of these block copolymers comprises of hard segments (usually polystyrene) connected by a flexible rubbery chain (polybutadiene or polyisoprene) in a linear or radial structure. Their flow characteristics have been studied and the results correlated with measurements in the solid state. They have been modelled mathematically based on two particular theoretical models. A liquid phase transition was recorded for both models, with appreciable reduction in the apparent activation energy of flow above this temperature. The quality of the domain structure depends on the continuity of the polystyrene phase and has been measured by the stress at yield and by the optical birefringence. A change in response was associated with the liquid-liquid transition.
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Wadham-Gagnon, Matthew. "Hyperelastic modelling of rubber behaviour in finite element software." Thesis, McGill University, 2006. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=99797.
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Experimental characterisation of rubber in uniaxial, equi-biaxial and planar tension under cyclic quasi-static loading shows strain-induced stress softening, hysteresis and unrecoverable strain. The objective of this work is to study the applications and limitations involved in predicting the behaviour of rubber with hyperelastic models. To assume a preconditioned perfectly elastic material, the data obtained from experiments must first be simplified. The data is then fitted to popular hyperelastic models in the finite element analysis (FEA) software ANSYS(TM). A single hyperelastic model (with given coefficients) is shown to only provide a good fit to a single characterisation test and level of preconditioning at the time. A two-iteration preconditioning method is developed using different hyperelastic models for a given material to approximate the softening effect of cyclic loading in a static FEA simulation. A biaxiality test is developed, providing information on the dominant mode of simple strain in the elements of a FE model. FEA simulations and experimental tests of a cantilevered rubber plate subjected to a bending load at its free end as well as a rubber guide lug subjected to a transverse deflection are presented and discussed. It is shown that using a single hyperelastic model is insufficient to predict the behaviour of these experiments in FEA simulations. The preconditioning iteration, when applied to these simulations, shows very good agreement with the experiments, both qualitatively and quantitatively. The biaxiality test provides insight on which characterisation test is the most appropriate for curve fitting hyperelastic models for a given analysis.
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Iwnicki, Simon. "The dynamic behaviour of railway vehicles with solid rubber tyres." Thesis, London South Bank University, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.280821.
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Skouvaklis, Gerasimos. "Rubber friction on ice and snow surfaces." Thesis, University of Edinburgh, 2011. http://hdl.handle.net/1842/9582.
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The friction of rubber on ice and snow surfaces is complex. Deeper scientific understanding is important for optimising performance of tyres in winter. Rubber, ice and snow systems exhibit frictional behaviour which depends on their material properties. The viscoelastic nature of rubber results in a higher real contact area compared to most other solids. At temperatures close or below the glass transition temperature, the frictional behaviour of rubber changes and its hardness increases. Thus, the real area of contact decreases, while the dissipation in the bulk of the rubber increases. Sliding of rubber on ice or snow leads to a temperature increase at the interface because of frictional heating, this can cause the surface to melt which decreases friction significantly. In this study we measured the friction of rubber on ice and snow and related the behaviour to mechanisms that occur. Key parameters affecting friction were examined and quantified. For this work a cold room and a new linear tribometer were specially designed and constructed. The rubber samples were made from various compounds and had different geometries. Typically they were the size of a “tread block element”. The geometries were chosen systematically to investigate the effects of surface area, sharp/rounded edges and sipes (small slits in the tread block that are used on snow tyres). A significant part of the work was developing consistent and reproducible ice and snow surfaces. New protocols were devised for these. The ice surfaces were made of de-ionised water, tap water and de-ionised water with salt. For the snow surface production: artificial snow was made and then compacted in a specially manufactured press, resulting in hard packed snow tracks for testing. Static and dynamic friction were investigated. Both were affected by speed, load, temperature and ice composition. The dynamic friction behaviour on ice was explained in terms of melt-water formation and the real area of contact of the rubber. The static friction was significantly affected by the losses inside the rubber bulk, the adhesive forces at the interface, and the time of stationary contact before the test. The investigation of rubber sliding on snow showed some similarities with sliding on ice; the surface of the rubber block slides over snow particles resulting in similar mechanisms as are seen on ice. However with snow there can also be a “ploughing” effect, where snow is cut by the leading edge of a sharp tread block. This effect contributes to friction. Experiments were made with simple rounded edged samples to avoid ploughing; the results showed the same trends as seen on ice, i.e. lower friction with increased speed, load and temperature. Investigations of siped tread blocks showed the same friction at low speeds as tread blocks without sipes. At higher speeds siped blocks exhibited less, or no, decrease in friction; more sipes gave less friction decrease. Our industrial collaborator, Michelin, made vehicle tests on snow using whole tyres with similar tread blocks. The trends they found were identical to our tests despite the dynamics of the system being more complex. This indicates how powerful the approach of using simple systematic experiments is for generating deeper understanding of the processes involved in sliding on ice and snow.
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Pinto, Nayra Alberici [UNESP]. "Compósitos à base de gesso incorporados com resíduos de borracha proveniente do processo de recauchutagem de pneus." Universidade Estadual Paulista (UNESP), 2017. http://hdl.handle.net/11449/151166.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
O gesso é o material sintético construtivo mais antigo que se tem notícia, e sua ampla utilização é devido as suas boas propriedades termoacústicas e de resistência ao fogo. No Brasil, seu emprego concentra-se em forros, revestimentos e paredes divisórias, conhecidas como gesso acartonado. Todavia, o gesso é um material sobre o qual existe pouco conhecimento ao nível da investigação. E este projeto se propõe a estudar mais esse material, através da confecção de compósitos a base de gesso com a incorporação de borracha de pneus, tornando-o assim um material sustentável. A borracha proveniente do processo de recauchutagem de pneus inservíveis tem ampla aplicação em pesquisas com concretos e argamassas; porém pouco se sabe sobre sua aplicação no gesso. Para atingir o objetivo proposto nesse trabalho serão feitos ensaios de microscopia eletrônica de varredura, resistência à ruptura na flexão, resistência à compressão, dureza superficial, absorção de água, densidade superficial de massa, consistência (mini-slump) e comportamento térmico. Dessa maneira, é possível afirmar que a incorporação de borracha pode ser interessante para a produção de placas de gesso, uma vez que pode incorporar um resíduo sem destino totalmente adequado, produzindo placas com características semelhantes das já utilizadas e ainda contribuindo em aspectos como densidade, dureza superficial e isolamento térmico. Sendo assim, dentre as granulometrias utilizadas neste estudo, a borracha grossa pode ser considerada a que teve melhor desempenho, uma vez que apresentou características de ser mais trabalhável, menos absorvente e mais isolante termicamente, além de apresentar resistências à compressão e a flexão adequadas para sua utilização (não estrutural), menores mossas e maior leveza do material.
Gypsum is the oldest constructive synthetic material ever heard, and their widespread use is due to its good thermoacoustic properties and fire resistance. In Brazil, its use is focused on linings, coating and partitions, known as drywall. However, the gypsum is a material on which there is little knowledge in terms of research. And this project aims to study more this material through the production of composite gypsum with tire rubber incorporation, thus making it a sustainable material. The rubber from the retreading process scrap tires has wide application in research on concrete and mortar; but little is known about its application in gypsum. In order to reach the objective proposed in this work, scanning electron microscopy, flexural strength, compressive strength, surface hardness, water absorption, bulk density, consistency (mini-slump) and thermal behavior will be performed. In this way, it is possible to affirm that the incorporation of rubber can be interesting for the production of gypsum boards, since it can incorporate a residue without destination completely, producing plates with characteristics similar to those already used and still contributing in aspects such as density, surface hardness and thermal insulation. Thus, among the granulometries used in this study, the thick rubber can be considered the one that had better performance, since it presented characteristics of being more workable, less absorbent and more thermally insulating, besides presenting resistance to compression and flexion adequate for its use (non-structural), smaller dents and greater lightness of the material.
FAPESP: 2015/17658-4
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Pinto, Nayra Alberici. "Compósitos à base de gesso incorporados com resíduos de borracha proveniente do processo de recauchutagem de pneus /." Ilha Solteira, 2017. http://hdl.handle.net/11449/151166.
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Orientador: Jorge Luís AkasakiResumo: O gesso é o material sintético construtivo mais antigo que se tem notícia, e sua ampla utilização é devido as suas boas propriedades termoacústicas e de resistência ao fogo. No Brasil, seu emprego concentra-se em forros, revestimentos e paredes divisórias, conhecidas como gesso acartonado. Todavia, o gesso é um material sobre o qual existe pouco conhecimento ao nível da investigação. E este projeto se propõe a estudar mais esse material, através da confecção de compósitos a base de gesso com a incorporação de borracha de pneus, tornando-o assim um material sustentável. A borracha proveniente do processo de recauchutagem de pneus inservíveis tem ampla aplicação em pesquisas com concretos e argamassas; porém pouco se sabe sobre sua aplicação no gesso. Para atingir o objetivo proposto nesse trabalho serão feitos ensaios de microscopia eletrônica de varredura, resistência à ruptura na flexão, resistência à compressão, dureza superficial, absorção de água, densidade superficial de massa, consistência (mini-slump) e comportamento térmico. Dessa maneira, é possível afirmar que a incorporação de borracha pode ser interessante para a produção de placas de gesso, uma vez que pode incorporar um resíduo sem destino totalmente adequado, produzindo placas com características semelhantes das já utilizadas e ainda contribuindo em aspectos como densidade, dureza superficial e isolamento térmico. Sendo assim, dentre as granulometrias utilizadas neste estudo, a borracha grossa pode ser consider... (Resumo completo, clicar acesso eletrônico abaixo)
Mestre
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Oba, Takeshi. "The fatigue behaviour of toughened epoxy polymers." Thesis, Imperial College London, 1999. http://hdl.handle.net/10044/1/11431.
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Rahman, Mohd Tahir Bin Abdul. "Further studies of the stress relaxation behaviour of rubber in compression." Thesis, Loughborough University, 1985. https://dspace.lboro.ac.uk/2134/7300.
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Part 1 - The Drying of Natural Rubber: This was the initial research programme to be carried out at the Institute of Polymer Technology as a result of renewed interest in the area following information feed-back from the natural rubber consumers indicating a problem of wet rubber contamination. However, due to the difficulty in producing an acceptable starting material, the work had to be terminated with the compilation of what had been achieved including the literature survey, trials to produce a representative field latex coagulum, dewatering, diffusion and absorption experiments. Part 2 - Further Studies of the Stress Relaxation Behaviour of Rubber in Compression: With the development of stress relaxation measuring equipment at the Institute of Polymer Technology, highly accurate and reproducible results were obtained from the 'ideal curves'. This equipment not only provides measurement of residual force and the instantaneous modulus of a sample but also enables the whole process from 'loading' to the measurement of subsequent relaxed stresses to be made.
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Lind, Petter. "A finite element material modelingtechnique for the hysteretic behaviour of reinforced rubber." Thesis, KTH, Hållfasthetslära (Avd.), 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-223949.
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Reinforced rubber is thanks to its elastic and dissipative properties found in industrialapplications such as isolators, flexible joints and tires. Its dissipative propertied comes from material related losses which have the effect that energy invested when deforming the material is not retained when returning it back to its initial state. The materiallosses are in turn caused by interactions in the material on a level below the micro scale.These interaction forms a macro stress strain response that is dependent on both strainamplitude, strain rate and temperature.It is thus a challenge to accurately model components made of reinforced rubber andand features of interest related to them, such as the rolling resistance for a tire. It is also difficult to device general design guide lines for such components due to rubbers many and complex dependencies and a simple accurate phenomenological model for modeling these properties are highly sought for in industry today.This thesis presents a method for modeling the strain amplitude and strain rate behavior for cyclically loaded rubber along with a method of choosing its material parameters.The proposed modeling technique results in a model with the same frequencydependency over all strain rates. An approximation which is shown to be valid over a few decades of strain amplitudes and rates and is believed useful for many industrialapplications. The material model presented can in addition be implemented in commercial FEsoftwares by using only pre-defined material models. This was achieved by implementationof the overlay method. The thesis also presents a method for how to implement the modeling technique in simulations with purpose to determine the rolling resistance of a truck tyre.Förstärkt gummi används, tack vare sina elastiska och dissipativa egenskaper, i industriella komponenter som exempelvis bussningar i drivlinan, däck och flexibla gummikopplingar. Dissipationen orsakas av materialförluster som i sin tur orsakas av interaktioner på längdskalor kortare än micro-nivå i materialet. Dessa Interaktioner resulterar i ett material som mekaniskt kan klassificeras som ett ickelinjärt material beroende av töjningsamplitud, töjningshastighet och temperatur. Det är därför en utmaning att göra modeller som på ett korrekt sätt förutsäger beteendet för gummikomponenter och egenskaper relaterade till dessa, som exempelvis rullmotståndet i ett däck. Det är även svårt att ge generella design riktlinjer för dessa komponenter på grund gummits många materialberoenden och enkla användvändbara fenomenologiska modeller som kan underlätta vid sådana processer är därför högt efterfrågade av industrin idag. I denna rapport presenteras en materialmodell för att modellera töjningsamplitud och töjningshastighetsberoendet för gummi under cyklisk last samt en metod för att välja dess materialparametrar. Den föreslagna materialmoddeleringstekniken resulterar i en modell med samma töjningshastighetsberoende för alla töjningsamplituder. En approximation som är användbar inom ett antal decader av töjningsamplituder och töjningshastigheter vilket borde vara tillräckligt för de flesta industriella tillämpningar idag. Den föreslagna materialmodellen kan dessutom implementeras i kommersiella FEprogramvaror genom att endast använda i programmet inbyggda materialmodeller. Detta sker genom tillämpning av overlay-metoden. I rapporten presenteras även en metod förhur modelleringstekniken kan implementeras genom en tillämpning i simuleringar med syfte att bestämma rullmotståndet för ett lastbilsdäck.
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Tsunoda, Katsuhiko. "The role of visco-elasticity on the crack growth behaviour of rubber." Thesis, Queen Mary, University of London, 2001. http://qmro.qmul.ac.uk/xmlui/handle/123456789/28950.
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This thesis concerns crack growth phenomena in rubber. It is widely known that a relationship exists between the magnitude of the stored energy release rate available to drive a crack, called the tearing energy (7'), and the resultant crack growth rate. For rubbers this basic relationship is said to be a characteristic of the material. The magnitude of T is related to both the visco-elastic losses and the crack tip diameter (d) However the actual size of d and its relationship with the viscoelastic losses is not clear. This thesis examines the crack growth behaviour in relation to d and the visco-elastic losses for a wide range of rubbers, whose visco-elastic properties are altered either by swelling in a liquid, altering the test temperature or the cross-link density and by the incorporation of fillers. Static, constant T, crack growth tests were carried out. These revealed that two different crack growth processes exist. For the fast crack growth process, T is determined by variations in the visco-elastic losses alone. For the slow crack growth process, T is determined by variations in both the visco-elastic losses and d. It is proposed here that the factors, which alter d, are associated with cavitation ahead of the crack tip for unfilled materials and with strength anisotropy for carbon black filled materials. In cyclic crack growth tests, the crack growth per cycle, dc/dn, can be considered to result from the sum of time and cyclic dependent crack growth components. For the first time, the detailed magnitudes of the contribution of each of these components to dc/dn have been determined, for a wide range of materials and mechanisms responsible for this behaviour are postulated. Also crack growth tests, both static and cyclic, were extended to very large extensions. Lastly this investigation revealed that the tensile strength for both ciystallising and noncrystallising rubber can be predicted using the tearing energy concept for a variety of loading regimes.
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Xiao, Keqin. "Fracture behaviour of rubber-modified epoxies and their carbon fibre-reinforced composites." Thesis, The University of Sydney, 2000. https://hdl.handle.net/2123/27762.
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Shorter, Robert. "The mechanical behaviour of elastomers when hollow microspheres are used as a particulate filler." Thesis, Queen Mary, University of London, 2014. http://qmro.qmul.ac.uk/xmlui/handle/123456789/9092.
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This study aims to understand the behaviour of a novel elastomer where hollow microspheres are used as a particulate filler. The behaviour of elastomers filled with rigid particles, is fairly well understood, where the stiffness increases as the amount of filler material is increased, alternatively, foamed elastomers which are usually produced with either closed cells or open cells, have been shown to become softer as the volume of the voids are increased. When traditional foam materials are compressed they exhibit non-linear behaviour in three distinct phases, the cell walls firstly bend, then they buckle and this is followed by densification. To understand the overall physical behaviour of the material, tensile tests of the elastomer material were conducted using unfilled materials and filled with a range of the hollow sphere filler volume fractions. Compression tests were also conducted on small cylinders, again using unfilled and filled rubbers with a range of filler volume fractions. The physical tests showed that increasing the filler volume fraction increased the reinforcing effect at low strains with an associated increase in stiffness, but the material then became increasingly less stiff at higher strains. To understand the behaviour of the bulk material, the mechanical behaviour of single hollow spheres under strain were investigated, both as a standalone material and then also embedded in an elastomer. To examine the mechanical behaviour of a single hollow plastic sphere a single microsphere was compressed using nano-indentation, the tests were then replicated at a larger scale using model table tennis balls. FEA software was used to model the behaviour of both types of hollow sphere, as well as a wide range of other spheres to better understand their buckling behaviour, to help predict the behaviour of microspheres with different ratios of wall thickness to diameters. To examine the behaviour of hollow spheres in a rubber matrix, simple cylindrical unit cells were made with a single hollow plastic sphere embedded within them. These model cylinders were produced with a translucent elastomer containing a single table tennis ball. Their behaviour in compression and in tension and that of a single hollow plastic sphere embedded in an elastomer was also modelled using FEA software, the effects of debonding and buckling were determined for small and large strains and were used to examine the more complex behaviour of the filled composite. A comparison between the measured behaviour and the various models indicates that the bulk behaviour of the microsphere filled elastomers is primarily determined by a progressive dewetting process of the rubber away from the microsphere in tension and by buckling phenomena of the hollow spheres in compression.
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Kind, David J. "Formulation and burning behaviour of fire retardant polyisoprene rubbers." Thesis, University of Central Lancashire, 2011. http://clok.uclan.ac.uk/2815/.
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This research aimed to develop new fire retardant rubber formulations, by surveying the existing knowledge base for fire retardant approaches for polyisoprene rubber, characterising unmodified compounds, formulating and studying fire retarded compounds for use within suspension and anti-vibration mounting systems. Materials have been prepared on a bench scale and evaluated for physical properties. Thermal decomposition has been studied using Thermogravimetric Analysis (TGA) in both air and nitrogen. Burning behaviour has been studied using a horizontal burning rate method, Limiting Oxygen Index (LOI) and the cone calorimeter. Basic rubber mixtures were prepared to investigate the interactions between the polymer and additives, under TGA conditions. Zinc oxide was found to have little effect on the polymer decomposition, while silica reduced thermal stability. When decomposed in air, increasing levels of carbon black reduce the rate of mass loss in the polymer. Comparing formulations with different cross-linking types, sulphur without cross-linking increases the heat release in a cone calorimeter; but when low levels of sulphur form efficient cross-links, heat release is suppressed, as also occurs with organic peroxide cross-linking. The effect of carbon black on burning behaviour was compared with inorganic fillers. Within the cone calorimeter, material containing carbon black formed a char-like residue which provides some reduction in the rate heat release, and did not contribute to the fuel load. The use of inorganic fillers yielded more rapid burning behaviour. Any level of carbon black addition gives a reduction in the rates of heat, smoke, CO, and CO2 release, confirming that carbon black had a stabilising effect. Intumescent formulations were prepared using ammonium polyphosphate (APP), pentaerythritol and melamine, and separately using expandable graphite (EG). Within the cone calorimeter both systems yielded a significant reduction in the first peak of heat release rate, but a much higher second peak than for the unmodified compound. This second peak value is associated with the significant levels of intumescence observed. The use of EG gave a greater level of fire retardance compared to the APP formulation. Hydrated fillers, and blends thereof, were investigated; an equal blend of aluminium hydroxide (ATH) and magnesium hydroxide (MH) was found to yield the lowest peak release rate on the cone calorimeter. Hydrated fillers were investigated with synergists proposed in the literature. Little benefit was noted for these additives when used as partial replacements for the filler.
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Caborgan, Rodica. "Contribution à l’analyse expérimentale du comportement thermomécanique du caoutchouc naturel." Thesis, Montpellier 2, 2011. http://www.theses.fr/2011MON20203/document.
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Une analyse du comportement thermomécanique du caoutchouc naturel est réalisée en combinant deux techniques d'imagerie quantitative. La corrélation d'images visibles sert à estimer les déformations puis l'énergie de déformation alors que des images infrarouges permettent d'estimer, via l'équation de diffusion, les quantités de chaleur mise en jeu. La construction de bilans d'énergie montre alors l'importance relative des mécanismes dissipatifs et de couplage thermomécanique. A basse fréquence pour de faibles déformations, les résultats permettent de retrouver le fameux effet d'inversion thermoélastique. A déformation plus importante, les résultats montrent une compétition sur le plan énergétique entre élasticité entropique et mécanismes de cristallisation/fusion sous contrainte. Aucun effet dissipatif significatif n'est détecté à basse comme en haute fréquence alors que dans chaque cas, sur le plan mécanique, une aire d'hystérésis caractérise la réponse cyclique du matériauAn analysis of the thermomechanical behavior of the natural rubber is carried out by combining two quantitative imaging techniques. The digital image correlation of visible images is used to estimate the strain and then the deformation energy whereas infrared images make it possible to estimate, via the heat equation, the amounts of heat involved in the material transformation. The construction of energy balance enables us to determine the relative importance of the dissipative and thermomechanical coupling mechanisms. For low frequency and low extension ratio, the results show the famous thermoelastic inversion effect. From an energy standpoint, a competition between entropic elasticity and stress-induced crystallization/fusion mechanisms is observed for more significant extension ratios. No significant dissipative effect can be detected at low or high loading frequency whereas in each case, a stress-strain hysteresis characterizes the cyclic response of the material
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Nehr, Jonas Christian. "Damping and Thermomechanical behaviour of CFRP laminates modified with rubbery nanofibers." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2020. http://amslaurea.unibo.it/21702/.
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Nanofibrous membranes are a promising material for tailoring the properties of laminated CFRP composites by embedding them into the structure. This project aimed to
understand the effect of number, position and thickness of nanofibrous modifications specifically on the damping behaviour of the resulting nano-modified CFRP composite
with an epoxy matrix. An improvement of damping capacity is expected to improve a composites lifetime and fatigue resistance by prohibiting the formation of microcracks
and consequently hindering delamination, it also promises a rise in comfort for a range of final products by intermission of vibration propagation and therefore diminution of
noise. Electrospinning was the technique employed to produce nanofibrous membranes from a blend of polymeric solutions. SEM, WAXS and DSC were utilised to
evaluate the quality of the obtained membranes before they were introduced, following a specific stacking sequence, in the production process of the laminate. A suitable curing cycle in an autoclave was applied to mend the modifications together with the matrix material, ensuring full crosslinking of the matrix and therefore finalising the production process. DMA was exercised in order to gain an understanding about the effects
of the different modifications on the properties of the composite. During this investigation it became apparent that a high number of modifications of laminate CFRP
composites, with an epoxy matrix, with thick rubbery nanofibrous membranes has a positive effect on the damping capacity and the temperature range the effect applies in. A suggestion for subsequent studies as well as a recommendation for the production of nano-modified CFRP structures is included at the end of this document.
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Najim, Khalid Battal. "Determination and enhancement of mechanical and thermo-physical behaviour of crumb rubber-modified structural concrete." Thesis, University of Nottingham, 2012. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.587844.
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This study aims are to i) understand and improve the bonding characteristics between crumb rubber and cement paste, and ii) scale-up the use of the material from lab to full-sized reinforced sections. Firstly a parametric investigation was conducted to determine the effect of crumb rubber replacement on the fresh, mechanical and thermo-physical properties of Plain Rubberised Concrete (PRC) and Self-compacting Rubberised Concrete (SCRC) at different w/c ratios. Secondly, the relative effects of different pre-coating/ treating methodologies were evaluated in terms of ITZ porosity, interfacial bonding, and mix air entrapment. These micro structural characteristics were compared to the resultant macro- scale mechanical and dynamic properties in order to evaluate the effectiveness of each treatment method. Thirdly, the large-scale serviceability of steel-reinforced PRC and SCRC was experimentally measured and assessed in terms of mechanical structural behaviour, steel reinforcement bond-slip strength, and material durability including chloride ion diffusion and water penetration. It was found that although crumb rubber incorporation decreases the workability/flowability, compactible mixes could be achieved even with zero-slump. Mortar pre-coating was found to be the most effective surface treatment method in improving both the mechanical behaviour and toughness of PRC and SCRC. It caused an elongation in the micro-crack path length at the rubber/ cement interface due to roughening of the surface morphology, leading to increased fracture energy dissipation! stress relaxation. Crumb rubber incorporation led to unusual thermo-physical properties as thermal conductivity decreased whilst volumetric heat capacity increased, with a pronounced moisture-dependency caused by air entrapment. Consequently, the concrete elements were found to store more heat energy, whilst increasing their resistance to heat exchange with the ambient environment. Interestingly, incorporating crumb rubber offers a significant reduction in interior air temperature fluctuations, which is important in terms of building thermal efficiency and comfort. It was found that both PRC and SCRC could be promising structural materials, with preference to SRCR, to be used for casting indoor-use structural members, especially for domestic buildings.
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Awang, Ngah Shamsiah. "Static and fatigue behaviour of fibre composites infused with rubber- and silica nanoparticle-modified epoxy." Thesis, Imperial College London, 2013. http://hdl.handle.net/10044/1/14432.
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Delamination has been recognised as the primary defect in composite structures, which can lead to rapid deterioration of the structure. This is because delamination is barely visible damage, and the presence of delamination crack growth between the fibre-matrix layered structure can severely reduce the load bearing capability without being noticed. The present work investigates the matrix toughening approach via the addition of a second phase copolymer and rigid silica nanoparticles in an attempt to enhance the delamination resistance in Glass Fibre (GF) composites. This investigation includes the analysis of the structure/property relationships of toughened epoxy matrices and their corresponding GF composites under quasi-static and fatigue loading conditions. The toughness performance and the toughening mechanisms of the modified epoxies and their corresponding composites are the main theme of this thesis. This investigation revealed a positive correlation between the interlaminar fracture toughness of GF composites and the toughness of the matrix phase. A large toughness increase was observed when using rubber-modified and core-shell rubber (CSR)-modified epoxy matrices. The use of a silica nanoparticle-modified matrix only showed a marginal toughness increase, and in some epoxy systems, the addition of silica nanoparticles was detrimental to the composite toughness. In the hybrid-modified matrix, the largest toughness increase was observed, indicating the presence of a synergistic effect between the rubber particles and silica nanoparticles. The toughening mechanisms in the rubber-modified epoxy were rubber particle cavitation and plastic void growth, whereas in the CSR-modified epoxy the toughening mechanisms were cavitation of the rubbery core and shear deformation in the polymer matrix. In the silica nanoparticle-modified epoxy, debonding of the nanoparticles and subsequent void growth were evident, but the energy dissipation was small and not sufficient to contribute to the large toughness increase. In addition, the silica nanoparticles increased the matrix stiffness and caused the matrix to be less adhered to the fibre surface, thus promoting a fibre-matrix interfacial failure. The fatigue performance of the GF composites with toughened matrices was analysed in terms of fatigue crack growth and fatigue threshold. The addition of rubber particles and silica nanoparticles reduced the fatigue crack growth rate and increased the fatigue threshold values. The fatigue threshold was further increased when using the hybrid-modified matrix suggesting a synergistic toughening effect in the threshold region. Microscopy analysis revealed there were no appreciable difference in the toughening mechanisms between the fatigue and quasi-static fracture behaviour.
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Rao, Tingling. "Effect of Crosslink Density and N660 Carbon Black on Tearing Behaviors of Natural Rubber Vulcanizates." University of Akron / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=akron1347122467.
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