Orientador: Fernando Galembeck / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Quimica / Made available in DSpace on 2018-08-14T14:09:30Z (GMT). No. of bitstreams: 1 Linares_ElisangelaMoura_M.pdf: 5164980 bytes, checksum: d9e4505544f0a48a985e78fccc9e1832 (MD5) Previous issue date: 2009 / Resumo: Este trabalho mostra o efeito da distribuição de espécies iônicas na morfologia e nas propriedades mecânicas de filmes de blendas de látices, e também demonstra o uso da técnica de microscopia eletrônica de transmissão por energia filtrada (EFTEM) para caracterização morfológica das blendas e de seus nanocompósitos com argila, explorando a região de baixa perda de energia de elétrons. Blendas de látex de borracha natural (NR)/poli(estireno-acrilato de butila) [P(S-BA] e NR/poli(cloreto de vinila) [PVC] foram investigadas, utilizando-se microscopia de varredura de potencial elétrico (SEPM). Através dos mapas de potencial elétrico, foi verificada a ocorrência de migração de espécies iônicas da blenda de uma fase polimérica para a outra, durante a preparação da blenda. Esta migração é espontânea, porque permite a redução da energia do sistema através da diminuição da repulsão eletrostática entre íons, distribuindo-os entre as fases, e é direcionada para o polímero que inicialmente tem menor concentração de cargas e apresenta maior constante dielétrica. Os domínios formados pelos dois componentes da blenda apresentam sinais de carga opostos, o que contribui para o aumento na compatibilidade, através da adesão eletrostática. Os espectros de baixa perda de energia mostram diferenças nas estruturas moleculares dos polímeros das blendas. Essas diferenças se expressam através de mudanças de contraste em imagens de perda de energia (mapas moleculares) adquiridas entre 20 e 90 eV. Blendas de NR/P(S-BA), P(S-BA)/PVC, P(S-BA)/poli(estirenometacrilato de 2-hidroxietila) e seus respectivos nanocompósitos foram analisados por EFTEM que revelou domínios em escala nanométrica, mesmo tendo pequenas diferenças na composição química, sem a necessidade de corar a amostra. Nos nanocompósitos, a disposição das lamelas de argila foi revelada graças ao cancelamento do contraste entre os polímeros. / Abstract: This work shows the effect of ionic specie distribution on the morphology and on the mechanical properties of latex blend films, as well as it demonstrates the use of energy-filtered transmission electron microscopy (EFTEM) technique to morphological characterization of these blends and its clay nanocomposites, by exploring the low-loss electron energy region. Natural rubber (NR)/poly(styrenebutyl acrylate) [P(S-BA)] and NR/poly(vinyl chloride) [PVC] blends were investigated by scanning electric potential microscopy (SEPM). Using the electric potential maps, it has been observed ionic specie migration from one polymer phase towards the other, during blend preparation. The migration is spontaneous because it allows the reduction of system energy thanks to the decreasing of ionion electrostatic repulsion given by ion distribution throughout the phases. The migration is directed towards the polymer that has initially the lower charge concentration and that presents the higher dielectric constant. The domains formed by the two blend component present opposite charge signals, which contribute to compatibility enhancement through electrostatic adhesion. Low-energy-loss electron spectra show differences on molecular structure of polymers that form the blends. Such differences are expressed through contrast changing in low-energyloss images (molecular maps) acquired between 20 and 90 eV. NR/P(S-BA), P(SBA)/ PVC, P(S-BA)/poly(styrene-2-hydroxyethyl metacrylate) and their respective clay nanocomposites have been analyzed by EFTEM without staining and it revealed nano-sized domains, even when chemical composition was slightly different. Clay platelet distribution within nanocomposites was revealed due to contrast canceling of polymer domains on EFTEM images. / Mestrado / Físico-Química / Mestre em Química

Orientador: Antonio Baldo Geraldo Martins / Banca: Erivaldo José Scaloppi Junior / Banca: Sergio Valiengo Valeri / Resumo: A seringueira é propagada vegetativamente pelo método da enxertia e suas sementes usadas para a obtenção dos porta-enxertos. Problemas ambientais relacionados ao desenvolvimento das plantas pelo sistema convencional e o estabelecimento de normas (Resolução SAA - 154/2013 do Estado de São Paulo) para a formação de mudas têm motivado estudos de novos processos para formação de porta-enxertos. O objetivo deste trabalho foi avaliar a produção suspensa de porta-enxertos de seringueira em ambiente protegido e a céu aberto. Foi realizado um experimento de semeadura e um de desenvolvimento de portaenxertos no município de Tanabi - SP. Comparou-se a germinação e o vigor de sementes de seringueira entre diferentes sistemas de semeadura: convencional em canteiros de germinação e direta em substrato sobre bancada protegida e a céu aberto. Foram avaliados o índice de velocidade de emergência e a porcentagem de germinação das sementes em cada sistema de semeadura. Os resultados obtidos nas condições experimentais permitiram concluir que o sistema de semeadura direta em substrato em ambiente protegido é o mais indicado por proporcionar melhor germinação das sementes e adequação à legislação, e que é fundamental a utilização de sementes com alto vigor. O experimento de desenvolvimento de portaenxertos avaliou o sistema de produção de mudas convencional nas condições de campo em comparação com o sistema suspenso em bancada, em ambiente protegido e a céu aberto. Foram avaliados o diâmetro a cinco cm do colo, a altura, a área foliar, o volume de raiz e a matéria seca da parte aérea e do sistema radicular das plantas. Concluiu-se que, na região do planalto ocidental paulista, a produção de porta-enxertos de seringueira deve ser conduzida em sistema de bancada protegida e com uso de substrato orgânico / Abstract: Rubber trees are propagated by grafting method and its seeds used for obtaining the rootstocks. Environmental problems related to rootstocks development by the conventional system and the establishment of rules (Resolução SAA - 154/2013 of the São Paulo State) for production in suspended nurseries have motivated researches of new processes for rubber rootstocks production. The objective of this study was to evaluate rubber rootstocks production in suspended containers in a greenhouse and open skies. An experiment of seeding and another of development of rootstocks were conducted in Tanabi - SP/Brazil. The experiment of seeding compared the germination and vigor of rubber seeds among different seeding systems: conventional in soil beds, direct seeding on substrate in suspended containers in a greenhouse and at open skies. Emergence speed index and percentage of germination of seeds were evaluated in each seeding system. The results showed that the direct seeding system in the greenhouse is the most suitable for providing better seeds germination and adaptation to legislation, and that it is essential to use high vigor seeds. The experiment of development of rubber rootstocks evaluated the conventional production system under field conditions compared to greenhouse and open skies suspended containers systems. Diameter at five cm from colon, height, leaf area, root volume and dry weight of shoot and root system of the rootstocks were evaluated. It was concluded that, in the São Paulo Western Plateau region, the production of rubber rootstocks should be conducted in the greenhouse suspended containers system using an organic substrate / Mestre

The diploma thesis deals with the EPDM addition influence on ozone resistance of NR/SBR mixtures. The theoretical part summarizes knowledge about rubber processing, additivation and effects of ozone on vulcanized rubber. The experimental part aims on preparation of rubber blends and measurement of its mechanical, physical and rheological properties in dependance on their composition.

In the rubber hand illusion (RHI), a rubber hand is placed in front of the participant with the participant's hand out of sight. If both hands are touched simultaneously, the illusion typically occurs. Between RHI studies, differences can be seen in the setup, and results of the illusion strength are inconsistent. One of these differences can be the moving RHI, where the real and rubber hand make the same movements to induce the illusion. The differences led to uncertainty regarding the influence of spatial configuration (i.e., an arrangement of the setup within three-dimensional space) on the illusion of body ownership. With this meta-analysis, I quantify the illusion strength in the moving RHI to be able to conclude if spatial configuration influences the results. A total of nine studies were included that had a total of 391 participants. The results show that the synchronous condition has a stronger illusory effect than the asynchronous condition. However, due to heterogeneity, the sample size may not represent the general population. Sub-group analysis showed no major difference in the illusion strength between a vertical and horizontal setup. These observations do not correspond with classical RHI studies in which vertical and horizontal setups were compared. However, in this meta-analysis, only moving RHI studies were included. In the moving RHI, the experimenter does not enter the visual receptive field of the participant, which may explain why no differences between the setups were found. The results of this meta-analysis cannot be seen as definitive; more research is necessary.

Debido al deterioro que presentan actualmente los pavimentos y la gran brecha de la infraestructura vial en el Perú, de aproximadamente 24 mil km, la tecnología debe lograr que las nuevas redes de infraestructura vial respondan eficientemente a construcciones sostenibles con la incorporación de residuos de la industria, para mitigar los impactos ambientales que generan. En el Perú, cada día se generan residuos de caucho por el desecho de llantas y el aumento del parque automotriz, generando un impacto ambiental negativo. Estos residuos, tienen el gran potencial de ser una fuente reutilizable con la finalidad de ser incorporados sobre mezclas a base de cemento, reduciendo el impacto medioambiental, la huella de carbono y constribuyendo a la ejecución de pavimentos eco-sostenibles. En esta investigación, se estudió el comportamiento de 11 muestras de concreto utilizando caucho reciclado de tamaños de 20 y 25 mm, para reemplazar hasta un 50% del agregado fino del concreto. El diseño de mezcla contiene los parámetros de diseño para pavimentos urbanos de concreto, utilizando aditivos reductores de agua y de fragua. Los resultados de las pruebas indicaron que las muestras con incoporación de caucho, son resistentes a la compresión hasta reemplazos del 20%. Se obtuvo el módulo de rotura mínimo de 36 kg/cm2 con reemplazos hasta de 40%. La mezcla optimizada obtuvo una reducción en el costo de fabricación por metro cúbico de 2.9% y una reducción de la huella de carbono de 0,4%. / Must to the deterioration that pavements currently present and the large hole in road infrastructure in Peru, of approximately 24 thousand kilometers, technology must achieve that the new road infrastructure in the country respond efficiently to sustainable constructions with the incorporation of waste of industry, to mitigate the environmental impacts that generate. In Peru, every day rubber waste is generated by the waste of disused tires and the increase of the automobile park, generating a negative environmental impact. These wastes have the great potential of being a reuse source with the purpose of be incorporated on cement-based mixtures, reducing the environmental impact, the carbon footprint and contributing to the realization of eco-sustainable pavements. In this investigation, was studied the behavior of 11 concrete samples using recycled rubber of 20 and 25 mm sizes, to replace until 50% of the fine concrete aggregate. The mix design contains the design parameters for urban concrete pavements, using water reducer and retarder admixtures. The results of the tests indicated that the samples with rubber incoporation, in both sizes, are resistant to compression until to 20% replacements. The minimum modulus of rupture obtained was 36 kg/cm2 with replacements until to 40% of rubber replacement. The optimized mixture obtained a reduction in manufacturing cost per cubic meter of 2.9% and a carbon footprint reduction of 0.4%. / Tesis

Orientador: Aldo Eloizo Job / Banca: Ana Maria Pires / Banca: Renivaldo José dos Santos / Resumo: Com os avanços na área de construção civil e crescimento da população mundial, torna-se necessário desenvolver políticas para o gerenciamento e reaproveitamento dos resíduos gerados a fim de evitar descarte incorreto, contaminações ambientais além de gerar novos materiais de engenharia agregando valor aos resíduos. Para tanto, propõe-se o uso de borracha natural expandida como matriz polimérica para incorporação do resíduo de eucalipto, como carga de reforço, para a produção de biocompósitos aplicados como isolamento térmico e acústico na construção civil. O resíduo de madeira foi micronizado e incorporado a borracha natural nas proporções de 20, 40 e 60 phr. A estrutura celular bem como a densidade relativa, densidade celular, tamanho e distribuição dos poros nos compósitos foram estudados. Determinou-se sua capacidade de isolamento térmico pelo método da fonte plana transiente (TPS) e acústico por meio do tubo de impedância. As espumas de BN/M40 e BN/M60 apresentaram ampliação da capacidade de isolamento acústico em relação a borracha natural, sem resíduos, atribuído uma redução no tamanho de poros e espessamento de paredes de células. BR/M40 registrou o maior pico de absorção de 0,83 a uma frequência de 3257 Hz, mais de três vezes maior que a borracha natural, semelhante à absorção de poliuretano que apresenta cerca de 0,70 para espumas rígidas e 0,90 para os flexíveis a 4000 Hz. O compósito BN/M60 mostra uma absorção distinta entre 1500 e 2500 Hz, o que indica que as amos... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: With advances in the area of civil construction and world population growth, it becomes necessary to develop policies for the management and reuse of generated waste in order to avoid incorrect disposal, environmental contamination and, as consequence, generate new engineering materials adding value to the waste. Therefore, it is proposed the use of expanded natural rubber as polymeric matrix with incorporation of the eucalyptus residue as reinforcing filler for the production of ecocomposites to be applied as thermal and acoustic insulation in civil construction. The wood residue was micronized and incorporated into the natural rubber in proportions of 20, 40 and 60 phr. The cell structure as well as the relative density, cell density, size and pore distribution in the composites were studied. The thermal insulation capacity was determined by the transient flat source (TPS) and acoustic method by means of the impedance tube. The foams of NR/W40 and NR/W60 showed amplification of the acoustic insulation capacity in relation to natural rubber without residues attributed to a reduction in the pore size and thickening of cell walls. NR/W40 recorded the highest absorption peak of 0.83 at a frequency of 3257 Hz, more than three times higher than natural rubber, similar to polyurethane absorption which presents around to 0.70 for rigid foams and 0.90 for the flexibles at 4000 Hz. The NR/W60 composite shows a distinct absorption between 1500 to 2500 Hz which indicate that the sample... (Complete abstract click electronic access below) / Mestre

Due to its large flexibility, low-price, large availability, and properties lignin is seen as an important compound with a wide range of applications. The increasing demand of fossil-based rubber materials is causing a serious threat to the environment and it is contributing to plastic- and marine pollution, ozone depletion and carbon dioxide emission (CO2) [1,2]. Numerous toxicological researches highlight that Carbon black may act as a universal carrier of wide variety of chemicals of varying toxicity to the human body [3,4]. Consequently, researcher endeavours in finding sustainable and eco-friendlier alternatives. The aim of this thesis was to further investigate the possibilities of replacing carbon black with modified lignin in rubber elastomeric materials- for the development of sustainable tyre technology. The research questions for this thesis were divided in four parts:   How does lignin (unmodified and modified) structure affect the mechanical properties of the rubber compound? How does lignin affect the cross-link and vulcanisation of the rubber compound? How does lignin affect the dispersion of the rubber compound? Which modification of lignin is more compatible with the rubber compound? Lignin is the second most abundant biopolymer on earth (after cellulose) and is mainly extracted from black liquor, which is obtained as a by-product from the pulp- and paper. In this study, pure lignin was obtained from Lignoboost process (Lignocity) and underwent an esterification process of aldehydes (1. Protonic, 2. Butyric, 3. Isobutyric 4. Methacrylic and 5. Crotonic). LignoCity 2.0 is a project focusing on the development of sustainable products and processes connected to lignin. The structure of the modified lignin was characterized using a FTIR-spectra. Furthermore, seven different rubber compounds were produced at Anva Poly Tech, which is a company that manufactures rubber materials in Sunne, Sweden. The mechanical testing involved: Tensile strength, IRHD, Hardness, Rebound Resilience and Rheometer curve. It was observable that the addition of lignin in rubber compounds did not significantly improve the mechanical properties compared to conventional carbon black. However, the rheometer curves of the lignin samples clearly indicate an increase in scorch time and that lignin takes part in the vulcanization process, thus the delay in crosslinking phase.  In addition, it was visible that the fully replacement of carbon black with lignin (unmodified and modified) increased the elongation at break. Furthermore, the FTIR spectra indicated a complete and successful modification of lignin. In addition, compared to unmodified lignin, it was visible that the modified lignin significantly improved the mechanical properties. Therefore, it was possible to conclude that the configuration and double bonds of the aldehydes had an impact on the vulcanization process. Butyric and isobutyric lignin were the better choices compared to the other lignin samples. / De rådande miljöproblemen som: plast- och gummiutsläpp i havet, växthusgasutsläppet och den ekologiska utarmningen i kombination med den ökande efterfrågan av fossilbaserade material har lett till en ökad satsning på att hitta mer hållbara och miljövänligare alternativ [1, 2]. Kimrök i gummimaterial utgör en del hälsorisker och samtidigt har negativ påverkan på miljön. Flertals studier visar att långtidsexponering av kimrök kan ge allvarliga lungproblem och även cancer [3,4]. På grund av dess stora tillgänglighet, låga kostnad och unika egenskaper anses lignin vara en möjlig och intressant framtidskandidat för ersättande av fossila produkter. Syftet med denna studie var att undersöka möjligheterna om att ersätta kimrök med modifierad lignin i gummimaterial för utvecklandet av ’grönare däckteknologi’. Frågeställningarna i detta arbete var uppställda i fyra i olika delar: Hur påverkar tillsättningen av lignin (omodifierad och modifierad) gummiblandningens mekaniska egenskaper? Hur påverkar tillsättningen av lignin tvärbindningarna och vulkningen i gummiblandningen? Hur påverkas tillsättningen av lignin gummiblandningars dispersion? Vilken modifikation av lignin är mest kompatibel med gummimaterialet? Lignin är en organisk biopolymer som är den näst mest (efter cellulosa) förekommande biomassan i naturen och produceras som en biprodukt från pappers- och massa industrin. Ren lignin erhålls genom extraktion från svartlut med diverse isolations metoder. I detta arbete erhölls lignin genom Lignoboost processen från Lignocity.  Lignocity 2.0 är ett projekt som syftar till att utveckla, kommersiella och effektivisera hållbara processer och produkter med fokus på lignin. I detta arbete modifierades ligninet genom en s.k. esterfierings process av fem olika aldehyder 1.Propionic, 2. Butyric, 3. Isobutyric, 4. Methacrylic och 5. Crotonic som sedan undersöktes i en FTIR-spektra. Sju olika gummiblandningar skapades (inklusive ett gummi som endast innehöll kimrök och ett gummi som ej innehöll kimrök eller lignin). Gummiblandningarnas mekaniska egenskaper undersöktes på följande sätt: Dragstyrka, IRHD (Hårdhet), Hårdhet, studselasticiteten och reometrisk karaktärisering De ligninbaserade gummiblandningarna gav ingen signifikant förbättring i de mekaniska egenskaperna. Dock visade den reometriska kurvan att tillsättning av lignin gav en ökning i bränntid samt att ligninet gav en förskjutning i tvärbindningsfasen. Vidare gav den reometriska kurvan en indikation på att ligninet deltog i vulkaniseringsprocessen. Isobutyric lignin hade den högsta bränntiden. Det var även bevisat att tillsättningen av lignin gav en ökning i töjning. Modifieringen av lignin gav en signifikant förbättring av de mekaniska egenskaperna jämfört med omodifierad lignin. FTIR-spektrumet av ligninproven indikerade på en lyckad modifiering och koppling av aldehydgrupperna. Trots att de ligninbaserade gummiblandningarna inte förbättrade de mekaniska egenskaperna så kunde intressanta kopplingar mellan aldehydens konfigurationer, dubbelbindningar och vulkaniserings processen göras. Butyric och isobutyric visade bäst resultat jämfört de andra ligninproven.

This thesis explores the seperation of isomeric paraffins in organic chemistry and how the resulting mixture of hydrocarbons might be examined.

Q-Med är ett medicintekniskt företag som tillverkar medicintekniska produkter, exempelvis produkter som är baserade på gel som innehåller bland annat hyaluronsyra. Gelen är placerad i en spruta som innehåller en gummikolv som är i kontakt med gelen.Idag används allt mer polymera material för olika tillämpningar, bland annat som medicintekniska produkter och läkemedelsförpackningar i läkemedelsbranschen. Q-Meds produkter betraktas som medicintekniska produkter på många marknader. Medicintekniska produkter och läkemedelsförpackningar innehåller ofta material som består av polymerer, exempelvis gummi och plast. På dessa material ställs olika krav så att dessa inte kontaminerar den produkt de är i kontakt med, då detta kan leda till olika negativa konsekvenser, exempelvis toxiska reaktioner i kroppen eller sänkt effektivitet hos läkemedlet/produkten. I och med att polymera material används kan det förekomma olika föroreningar i dessa material, exempelvis tillsatsämnen och reaktionsprodukter. Om dessa substanser läcker ut brukar dessa kallas för ”leachables” och ”extractables” – det finns inga motsvarande namn på svenska. Organiska och oorganiska föreningar är exempel på vad som kan lakas ut ur gummit.Den här rapporten beskriver en studie av gummi (bromobutylgummi) som är i kontakt med en gelprototyp (Prototyp A och Prototyp A-L) för att se vilka föreningar som kan lakas ut från gummit ur perspektivet leachables/extractables. För att ta reda på vilka föreningar som lakas ut från gummit utsattes denna för olika betingelser, som olika pH, temperatur, lösningsmedel, placebolösning och kontakt med produkt. För att kunna analysera vilka föreningar som lakades ut ur gummit i både gasfas och vätskefas användes Solid Phase Micro Extraction (SPME) och GC-MS som analysmetoder. Tre SPME fibrer med olika egenskaper, exempelvis olika polaritet och selektivitet användes för insamling av extraherbara ämnen.Resultaten visar att olika föreningar lakas ut ur gummit. Vid försök att identifiera dessa med ett referensbibliotek för masspektra gav många av dessa föreningar en relativt låg sannolikhet (< 50 %) jämfört med de föreslagna föreningarna. Detta gör det svårt att avgöra om det är en särskild förening som lakas ut eller om det är något liknande ämne som lakas ut. I gasfasen hittades fler föreningar jämfört med vätskefasen. Detta beror bland annat på att det finns fler ämnen som är villiga att gå upp i gasfas på grund av deras affinitet gentemot provet, det vill säga hur villig en förening är att reagera gentemot en annan förening. Två föreningar som dyker upp i de flesta headspace analyserna är 1-Bromo-3-(2-bromoethyl)heptane och butylated hydroxytoulene (BHT).Slutsatsen är att några enstaka föreningar lakas ut från gummit, så som BHT och 1-Bromo-3-(2-bromoethyl)heptane. Vad det gäller de andra föreningarna som lakas ut är det är svårt att avgöra om dessa föreningar verkligen kommer från gummit eller från någon annan källa, exempelvis fiberns omgivning. Detta beror på att SPME-metoden är en känslig metod som kan fånga upp en rad ämnen från sin omgivning. Därför anses det att fler studier måste göras på detta område, fast med en metod som ger mer pålitliga resultat. / Q-Med is a medical device company that manufactures medical devices, for instance a product that is a gel containing hyaluronic acid. The gel is placed in a syringe component containing a stopper made of rubber that is in contact with the gel.Today, increasingly more polymeric materials for various applications are used, for example medical devices and pharmaceutical packaging in the pharmaceutical industry. The products of Q-Med are considered as medical devices in many markets. Medical devices and pharmaceutical packaging often contains materials composed of polymers, for instance rubber and plastics. For these materials there are different requirements so that they do not contaminate the product that they are in contact with. Contamination may lead to negative consequences, such as toxic reactions and a reduced effectiveness of the drug/product.Since it is polymeric materials that are used there might be some potential impurities in the material, these pollutants are called leachables and extractables. Organic and inorganic compounds are examples of what can leach out of the rubber.In this report the rubber (bromobutyl rubber) that is in contact with a gel prototype (Prototype A and Prototype A-L) is studied to see if the rubber leaches out some compounds of the perspective leachables/extractbales. To know if the rubber leaches out some contaminates the rubber was exposed to various conditions. For instance; different pH, temperature, solvent, placebo solution and contact with the product. In order to analyze which pollutants leached out of the rubber, Solid Phase Micro Extraction (SPME) and GC-MS where used as analytical methods. Three SPME-fibers with different polarity and selectivity where used for the collection of extractable compounds.The results show that the rubber leaches out different compounds. Many of these have a low probability compared to the spectra of masses in the used reference library. This makes it difficult to determine if there is special compound that leaches out or if it is a similar compound that leaches out. When compared, more compounds were found in the gas phase than the liquid phase. This is partly because there are more compounds that are willing to get up in the gas phase, because of the compounds affinity to the sample, for example different polarity. The two main compounds, which are found in the most headspace analyses, are 1-Bromo-3- (2-bromoethyl) heptane and butylated hydroxytoulene.The conclusion is that some compounds, for instance 1-Bromo-3- (2-bromoethyl) heptane and butylated hydroxytoulene leaches out in the gas phase. For other compounds it’s hard to determine if they come from the rubber or from another source from it’s surrounding. This is because the SPME-method is a sensitive method that can absorb a number of compounds from its surroundings. It is therefore considered that more studies must be done in this area but with another method that give more reliable results.

Two new aspects of the dynamic behaviour in the audible frequency range of magneto-sensitive (MS) rubber are highlighted: the existence of an amplitude dependence of the shear modulus—referred to as the Fletcher–Gent effect—for even small displacements, and the appearance of large MS effects. These results have been obtained experimentally and are subsequently used to model two examples of magneto-sensitive rubber isolators to show how by means of MS rubber they can be improved. The first model calculates the transfer stiffness of a torsionally excited isolator and the second one the energy flow into the foundation for a bushing inserted between a vibrating mass and an infinite plate. In both examples notable improvements in isolation can be obtained / QC 20101125