Smouldering combustion governs the burning of many materials in the built and natural environments. Smouldering is flameless, heterogeneous combustion which occurs when oxygen reacts with the surface of a solid fuel. Understanding the conditions which will result in the ignition and smouldering of a porous fuel is important and the phenomena involved are complex and coupled, involving heat and mass transfer, and chemical kinetics. This thesis reports experimental studies of the ignition, spread, suppression and emissions from reactions in porous media. Similar experimental techniques are shown in this thesis to be applicable when studying a wide range of solids which undergo self-sustaining reactions. This thesis is presented in a manuscript style. Each chapter takes the form of an independent paper which has been prepared for journal publication and as such, each chapter can stand on its own as a piece of research. A final chapter summarizes the findings and conclusions and suggests further areas of research. Chapter 1 presents a study of self-sustaining decomposition of ammonium nitrate containing inorganic fertilizer. This is of importance to the shipping industry which transports these materials in large quantities. Upon exposure to a heat source, ammonium nitrate may undergo exothermic decomposition which can propagate through the material, posing safety and economic threats. This reaction does not involve oxygenbased chemistry, but has many similarities to the propagation of a smoulder front in a porous material. Small-scale experiments to investigate the self-sustaining decomposition (SSD) behaviour of NPK (nitrogen, potassium, phosphorous) 16.16.16 fertilizer were undertaken. Experiments showed that this material will undergo self-sustaining decomposition and are used to formulate a reaction framework. Findings were applied to the events that occurred aboard the Ostedijk in 2007. Chapter 2 is a study of smoulder in polyurethane foam to study the relationship between sample size, critical heat flux and spread rate. Smouldering fires are the leading cause of residential fire deaths in developed countries and polyurethane foam is ubiquitous in the modern world. The critical heat flux for ignition was found to decrease with increasing sample size and the spread rate was found to be a function of the sample size, smoulder propagation depth and the applied heat flux. This is the first time that results on the effect of sample size on smouldering have been reported in the literature and these can be used to aid the extrapolation of small-scale flammability testing results to large scale scenarios. Chapter 3 presents an experimental investigation into the ignition of porous fuels by hot particles. This is related to the problem of spotting ember ignition in wildland fires which is a major, but poorly understood, spread mechanism. The process of spotting occurs in wildland fires when fire-lofted embers or hot particles land downwind, leading to ignition of new, discrete fires. The work studies the ignition of a fuel as a function of ember size and temperature. Metal particles are used as a proxy for burning embers and powdered cellulose to represent the forest fuel. Relationships between the size and temperature of the particle required for flaming and smouldering ignitions are found. These results are used to assess the ability of hot-spot ignition theory to determine the particle size–temperature relationship required for ignition of a cellulose fuel bed. Chapter 4 is an investigation into the suppression of smouldering coal. Subsurface coal fires are a significant global problem with fires in China alone estimated to consume up to 200 million tons of coal per year. As global demand for coal increases, accidental fires are a waste of a useful energy resource as well as a source of pollution and greenhouse gases. The results are the first attempt reported in the literature to study the suppression of these fires under controlled laboratory conditions. The ignition, spread and suppression of subsurface coal fires were studied using small-scale laboratory experiments. Time to ignition was seen to depend on particle size with small and large particles resulting in long times to ignition, while medium sized particles resulted in the shortest time to ignition. The maximum temperature, spread rate and mass lost were found to be independent of particle size above a critical particle size. The effectiveness of three systems for delivery of a suppression agent were assessed – direct injection, shower and spray. The effect of particle size on the water required for extinguishing using a spray was found to be weak. Chapter 5 presents an experimental investigation of the smouldering behaviour of peat. This is of particular interest in understanding the impact of smouldering fires on the earth system. The longer burn durations and different combustion dynamics of smouldering compared to flaming means that they have been shown to consume large amounts of biomass in, and contribute significantly to the emissions from, natural fires occurring in peatlands. The dynamics of smouldering peat in shallow, strong fronts was studied in the Fire Propagation Apparatus and a smoulder reaction framework with two burning regimes is presented. The first regime is peat smouldering and was found to be controlled by the applied heat flux and the second regime corresponded to char smouldering and was more sensitive to the flow of oxidizer. Chapter 6 complements Chapter 5 with an analysis of the CO and CO2 emissions for smouldering and flaming peat. This data can be used with large-scale measurement techniques to improve emission estimates. The emissions are found to be dependent of the burning regime and the type of combustion with flaming resulting in higher fluxes of CO2 and lower fluxes of CO compared to peat smouldering. Char smouldering resulted in the highest yields of CO and CO2. The large majority of emissions (85% of CO2 and 97% of CO) are released during the smoulder phase of the reaction. This highlights the differences in the chemical processes occurring under these two modes of combustion. Chapter 7 summarizes the research undertaken in this thesis and presents possible further work.

Concentrating quaternary (positive) charge at polymer surfaces is important for applications including layer-by-layer polyelectrolyte deposition and antimicrobial coatings. Prior techniques to introduce quaternary charge to the surface involve grafting of quaternary ammonium moieties to a substrate or using polyurethanes with modified hard segments however there are impracticalities involved with these techniques. In the case of the materials discussed, the quaternary charge is introduced via polyurethane based polymer surface modifiers (PSMs) with quaternized soft segments. The particular advantage to this method is that it utilizes the intrinsic phase separation between the hard and soft segments of polyurethanes. This phase separation results in the surface concentration of the soft segments. Another advantage is that unlike grafting, where modification has to take place after device fabrication, these PSMs can be incorporated with the matrix material during device fabrication. The soft segments of these quaternized polyurethanes are produced via ring opening copolymerization of oxetane monomers which possess either a trifluoroethoxy (3FOx) side chains or a quaternary ammonium side chain (C12). These soft segments are subsequently reacted with 4,4’-(methylene bis (p-cyclohexyl isocyanate)), HMDI and butanediol (BD) to form the PSM. It was initially intended to increase the concentration of quaternary ammonium charge by increasing PSM soft segment molecular weight. Unexpectedly, produced blends with surface microscale phase separation. This observation prompted further investigation of the effect of PSM soft segment molecular weight on phase separation in PSM-base polyurethane blends and the subsequent effects of this phase separation on the biocidal activity. Analysis of the surface morphology via tapping mode atomic force microscopy (TMAFM) and scanning electron microscopy (SEM) revealed varying complexities in surface morphology as a function of the PSM soft segment molecular weight and initial annealing temperature. Many of these features include what are described as nanodots (100-300 nm), micropits (0.5-2 um) and micropeaks (1-10 um). It was also observed that surface morphology continued to coarsen with time and that the larger features were typically observed in blends containing PSMs with low molecular weight soft segments. This appearance of surface morphological feature correlates with decreased biocidal activity of the PSM blends, that is, the PSM blends exhibit little to no activity upon development of phase separated features. A model has been developed for phase separation and concomitant reduction of surface quaternary charge. This model points the way to future work that will stabilize surface charge and provide durability of surface modification.

To create functional surfaces for soft materials, such as polyurethanes, our approach is to use a semifluorinated surface modifier as minor component to the matrix material. The surface modifier, driving by reduction in surface energy, surface-concentrates to form a functionalized surface layer at the air-polymer interface. In our previous studies, linear PTMO-based polyurethanes were used as the matrix material. These systems undergo slow surface phase separation at room temperature due to the thermodynamically immiscibility of the soft blocks. In this study, chemically crosslinked matrix was developed to provides a steric hindrance to constrain the mobility of surface modifier and to form a kinetically stable surface. The physical property and morphology of base crosslinked matrix has been characterized using DSC, UTT, DMA and AFM. The surface morphology of surface modified crosslinked matrix has been characterized using AFM, DCA and XPS.

The goal of this research is to cover a broad set of scientific investigations of elastomeric materials based on polydimethylsiloxane (PDMS) and poly((3,3,3-trifluoroethoxymethyl)methyloxetane) diol. The scope of study covers five areas, well correlated with each other. The first study investigates the near surface morphology of condensation cured PDMS as a function of increasing the amount of siliceous phase. The appearance, disappearance and reappearance of untreated fumed silica nanoparticles at the PDMS near surface and their correlation with the volume fraction of siliceous phase have been studied. This research with PDMS nanocomposites has led to the development of an alternative route for improving mechanical strength of PDMS elastomers, conventionally known to have weak mechanical properties. The second study involves synthesis of a triblock copolymer comprising of four mutually immiscible phases, namely, soft segments comprising of fluorous and silicone domains, a diisocyanate hard segment and a glassy siliceous phase. Structure-property relationship has been established with an investigation of the interesting surface and bulk morphology. The highly improved mechanical strength of these soft materials is noteworthy. The dominance of silicone soft block at the triblock near surface has led to the third study which investigates their potential non-adhesive or abhesive characteristic in both a laboratory scale and in a marine environment. The peak removal stress and the removal energy associated with the detachment of a rigid object from the surface of these triblock copolymers have been measured. Results obtained from laboratory scale experiments have been verified by static immersion tests performed in the marine environment, involving the removal of adhered soft and hard fouling organisms. Gaining insights on the characteristics of an easy release surface, namely low surface energy and a low near surface modulus, a new way for controlling the near surface composition for elastomeric coatings have been developed. This technique involves an elastomer end-capped with a siliceous crosslinking agent and a tough, linear polyurethane. The basic concept behind the hybrid compositions is to develop a coating suitable for foul release applications, having a low energy surface, low surface modulus but good bulk mechanical strength. Henceforth, the fourth study deals with synthesis and characterization of the hybrid polymers over a wide range of composition and investigates their foul release characteristic in laborartory scale experiments. In our final study, attempts have been made in generating a silicone coating with antimicrobial property. A quaternary alkylammonium in different weight percents have been incorporated into a conventional, condensation cured polydimethylsiloxane (PDMS) elastomer. Antimicrobial assay has been performed on these modified silicone coatings to assess their biocidal activity against strains of Escherichia coli, Staphylococcus aureus and Pseudomonas aeruginosa. Surface accessibility of quaternary charges has been quantified by measuring the streaming potential of a modified coating. An effort has been made in improving the mechanical strength of the weak PDMS elastomers by adding treated fumed silica nanoparticles as reinforcements. The effect of adding fillers on the mechanical property (tensile), surface concentration of quaternary charge and on the biocidal activity of a representative sample has been investigated.

Parmi tous les plastiques, les polyuréthanes (PUs) représentent la sixième classe de polymères la plus utilisée au monde. Ils sont synthétisés industriellement par réaction entre un diol et un diisocyanate, en présence d'un catalyseur métallique et d’un solvant organique.Néanmoins, cette synthèse présente d’importants problèmes environnementaux et de santé.Afin de s’affranchir de ces composés toxiques, les progrès dans ce domaine ont conduit à un certain nombre de procédés sans isocyanates. Néanmoins, ces procédés doivent faire face à de nombreux défis (propriétés physiques, masses molaires, réactions secondaires, etc.), afin de concurrencer les polyuréthanes classiques. Par conséquent, une partie de ce manuscrit est dédiée à une étude rationnelle de l'influence de catalyseurs organiques, tels que le TBDou P4, non seulement sur la cinétique de polymérisation de l’aminolyse de carbonates biscycliques,mais aussi sur la structure et les propriétés des PUs résultants. Par la suite, et afin de limiter l’utilisation de composés organiques volatiles, des dispersions aqueuses de polyuréthanes sans isocyanates ont été obtenues en adaptant : 1) le procédé acétone à l’aminolysis de carbonates bis-cycliques et 2) la polymérisation interfaciale à la polycondensation de dicarbonates linéaires avec des diamines. / Among all plastic materials, polyurethanes (PUs) represent the 6th most popularly usedpolymers in the World. They are industrially synthesized by the reaction between a diol and adiisocyanate, in the presence of a metal catalyst and an organic solvent. Nevertheless, thissynthesis presents important environmental and health problems. In order to replace thesetoxic compounds, advances in this field have led to a number of isocyanate-free processes.However, these processes have to face many challenges (physical properties, molarmasses, side reactions, etc.), in order to compete with conventional polyurethanes.Therefore, part of this manuscript is dedicated to a rational study of the influence oforganocatalysts, such as TBD or P4, not only on the polymerization kinetics of the aminolysisof bis-cyclic carbonates, but also on the structure and properties of the resulting PUs.Subsequently, and in order to limit the use of volatile organic compounds, aqueousdispersions of non-isocyanate PUs were obtained by adapting: 1) the acetone process to theaminolysis of bis-cyclic carbonates and 2) the interfacial polymerization to thepolycondensation of linear dicarbonates with diamines.

As patologias que acometem os membros superiores são bastante incapacitantes para os seres humanos, pois elas são sua principal ferramenta de interação com o mundo tanto pelo papel nas tarefas cotidianas quanto pelo simbolismo que carregam. Na Terapia Ocupacional o objetivo é promover uma melhor qualidade de vida, maior autonomia e participação no cotidiano e, dentre os recursos e abordagens possíveis no processo de reabilitação, as órteses têm grande destaque, pois seu uso correto pode \"aumentar a função, prevenir ou corrigir deformidade, proteger estruturas em processo de cicatrização, restringir o movimento e permitir o crescimento ou remodelação tecidual\" (FESS, 2002, p.98). As órteses mais utilizadas na prática clínica são confeccionadas em material termomoldável de baixa temperatura. Não há opções nacionais deste material, implicando na necessidade de importação que pode gerar dificuldades no acesso a este tipo de material. Leite (2007) desenvolveu um poliuretano derivado do óleo vegetal (mamona) que se mostrou apto para a confecção de órteses após ensaios mecânicos, térmicos e clínicos, mas que necessita de melhorias, principalmente em relação aos aspectos de maleabilidade (moldabilidade) e memória do material. O presente trabalho tem como objetivos caracterizar o material desenvolvido e alguns existentes no mercado e modificar o material desenvolvido por Leite (2007). Para tanto, foram introduzidas modificações - acréscimo de cargas e mudanças na proporção poliol e pré-polímero - e realizados ensaios mecânicos e térmicos de Memória, Dureza, Moldabilidade, Análise Dinâmico-Mecânica, Tração, Temperatura no Contato com a Pele Humana e a velocidade de Resfriamento do material. Os resultados indicam que o acréscimo de Sílica Pirogênica e o aumento da proporção de poliol em relação ao pré-polímero melhoraram a moldabilidade do material e tornaram a memória adequada aos propósitos. Conclui-se que o novo material, o compósito CPU POS, é mais rígido que os importados, suportando maior carga, é seguro para o paciente do ponto de vista de temperatura e possui uma grande validade. A moldabilidade é rápida e necessita que o terapeuta posicione o material, pois ele não se acomoda com a ação da gravidade. A dureza foi diminuída, embora ainda seja maior que a dos materiais de comparação. Assim, o presente estudo contribuiu para um maior conhecimento dos termomoldáveis existentes no mercado utilizados para confecção de órteses e aponta o poliuretano derivado de óleo vegetal, modificado com cargas, como um material adequado para este propósito. / Pathologies that affect the upper limbs are very incapacitating to humans, because they are your primary tool for interaction with the world, both thé role of everyday tasks as the symbolism they carry. In Occupational Therapy the objective is promote a better quality of life, more autonomy and participation in daily life and, among the resources and possible approaches in the rehabilitation process, the orthosis have great prominence, because their correct use can \"enhance function, prevent or correct deformities, protect structures in the healing process, restrict movement and support the growth or tissue remodeling\" (FESS, 2002, p.98). The most used orthosis in clinical practice are fabricated with low temperature thermoplastic. There are no national options of this material, resulting in import which can create difficulties in accessing this type of material. Leite (2007) developed a vegetable (castor) oil based polyurethane that proved suitable for orthosis, after mechanical, thermal and clinical testing, but needs improvements especially aspects of malleability (moldability) and memory of the material. The current work aims at characterizing the material developed and some of the existing materials and modify the material developed by Leite (2007). Therefore, changes have been introduced - increase of fillers and changes in the proportion polyol to prepolymer - and performed mechanical and thermal tests of Memory, Hardness, Moldability, Dynamic Mechanical Analysis, Traction, Temperature in contact with human skin and the speed Cooling the material. The results indicate that the addition of Pyrogenic Silica and increased proportion of polyol in relation to the prepolymer improved moldability ofthe material and made appropriate memory to the purpose. We conclude that the new material, composite CPU POS, is more rigid than the imported, supporting higher load, it is safe for the patient in terms of temperature and has a great validity. The moldability is fast and requires the therapist to position the material, because it does not settle by gravity. The hardness was decreased, although it is still higher than the comparison material. Thus, the present study contributed to a better understanding of existing market thermoformables used for orthosis and points the polyurethane derived from vegetable oil, modified with fillers, as a suitable material for this purpose.

O presente trabalho envolve um estudo das propriedades físico-químicas de uma poliuretana obtida a partir do óleo de mamona, desenvolvida pelo Grupo de Química Analítica e Tecnologia de Polímeros do Instituto de Química de São Carlos - USP. Este polímero apresenta-se como um material biocompatível, possuindo em sua estrutura molecular, segmentos derivados do óleo de mamona, um material renovável e de origem natural. Neste trabalho foram preparadas poliuretanas em diferentes proporções de pré-polímero e poliol. A caracterização das amostras foi realizada através das seguintes técnicas: espectroscopia de absorção na região do infravermelho, análise térmica (termogravimetria, estudo cinético de decomposição térmica por TG usando o método de Flynn-Wall-Ozawa e análise dinâmico-mecânica) e ensaio mecânico de resistência à tração. As propriedades avaliadas por termogravimetria, análise dinâmico-mecânica e ensaios de resistência à tração demonstram considerável influência com as mudanças nas proporções de pré-polímero e poliol adotadas, assim como, do poliol. A partir dos resultados das curvas termogravimétricas foi observado que o aumento do pré-polímero na proporção pré-polímero/poliol aumenta a perda de massa do primeiro evento de decomposição térmica da poliuretana. Assim como, na análise dinâmico-mecânica, a temperatura de transição vítrea apresentou aumento com o aumento da proporção no pré-polímero/poliol. Os ensaios mecânico de resistência à tração mostraram que o aumento do pré-polímero leva a um aumento da resistência à tração, enquanto diminui o alongamento. / This work study the physicochemical properties of a polyurethane obtained from castor oil, by the Group of Analytical Chemistry and Technology of Polymers, Institute of Chemistry of São Carlos - USP. This polymer appears as a biocompatible material, having in its molecular structure, segments derived from castor oil, a renewable material and of natural origin. In this work were prepared in different proportions polyurethane pre-polymer and polyol. The characterization of samples was performed using the following techniques: absorption spectroscopy in the infrared, thermal analysis (thermogravimetry, kinetics of thermal decomposition by TG using the method of Flynn-Wall-Ozawa and dynamic mechanical analysis) and mechanical test tensile strength. The properties evaluated by thermogravimetry, dynamic mechanical analysis and testing of tensile strength showed considerable influence with the changes in the proportions of pre-polymer and polyol adopted, as well as the polyol. From the results of thermogravimetric curves it was observed that the increase the pre-polymer in proportion of pre-polymer/polyol increases the loss mass in the first step of the thermal decomposition of polyurethane. Just as in dynamic mechanical properties, the glass transition temperature also showed an increase with increasing proportion of pre-polymer/polyol. The mechanical testing of tensile strength showed that the increase in pre-polymer leads to an increase in tensile strength, while decreasing the stretch.

Eletrodos compósitos à base de grafite/poliuretana foram preparados contendo diferentes quantidades de hexacianoferratos de cobre(II), cobalto(II) e ferro(III). Os complexos foram preparados de acordo como procedimentos descritos na literatura e caracterizados por análise elementar, análise térmica e espectrometria na região do infra-vermelho. A análise térmica mostrou que há 10 moléculas de água de hidratação no hexacianoferrato de cobre(II), 11 no hexacianoferrato de cobalto(II) e 16 no hexacianoferrato de ferro(III). Após desidratação ocorre decomposição exotérmica violenta dos complexos. No caso do cobre a decomposição se dá com formação de CuO seguida da degradação do Fe(CN)3 com formação de Fe2O3. Para o hexacianoferrato de cobalto(II) e o hexacianoferrato de ferro(III) a mistura de Co3O4/Fe2O3 e o Fe2O3, respectivamente, se formaram após uma única etapa de decomposição. Apenas os eletrodos preparados com os complexos de cobalto e cobre apresentaram sinais voltamétricos, enquanto que o complexo de ferro não respondeu, provavelmente devido à sua baixa solubilidade em água. As condições de preparação dos eletrodos, tais como composição, ordem de adição de reagentes, pH, eletrólito suporte e intervalo de potenciais foram otimizadas. Um mecanismo para explicar a não estabilização do sinal voltamétrico, mesmo após ciclagem de potencial foi proposto com base na baixa solubilidade dos sais em água e a sua imobilização no eletrodo sólido a qual dificulta a formação do filme de hexacianoferrato na superfície. Finalmente um método analítico para a determinação de piridoxina, usando o eletrodo de grafite/poliuretana modificado com hexacianoferrato de cobre(II) foi proposto, com base na redução de sinal do complexo, na presença do analito. Neste caso foi observada uma resposta linear entre 1,08 x 10-6 a 1,07 x 10-5 mol L-1, com limite de detecção de 8,78 x 10-7 mol L-1 (3 x S/N) e o método foi aplicado na determinação de piridoxina em duas formulações comerciais. Coeficientes de recuperação entre 98-120% foram observados sem interferência dos componentes das formulações e sem necessidade de renovação da superfície do eletrodo. / Graphite-poliurethane solid composite electrodes were prepared containing different amounts of copper(II), cobalt(II) and iron(III) hexacianoferrates. The complexes were synthesized according to procedures previously described and characterized using elemental analysis, infrared spectrometry and the thermal analytical techniques: thermogravimetry/derivative thermogravimetry and differential thermal analysis. The thermal analysis revealed that there are 10 hydration water molecules in the copper(II) hexacianoferrate, 11 in the cobalt(II) and 16 in the iron(III) complexes. After dehydration, a strong exothermal degradation occurred in all cases. The copper complex decomposed in two steps with generation of CuO, followed by degradation of the Fe(CN)3 and formation of Fe2O3. The cobalt(II) and iron(III) hexacianoferrates decomposed in a single step with generation of Co3O4/Fe2O3 mixture and Fe2O3 as residues respectively. Only the electrodes prepared with copper and cobalt complexes presented voltammetric signals, while the iron complexes did not responded, probably due to its very low solubility in water. The conditions for the electrode preparation such as composition, order of addition of the components supporting electrolyte, pH and useful potential window were optimized. A mechanism to explain the non-stabilization of the voltammetric signal even after 200 cycles has been proposed on the basis of the complexes solubility in water as well as the immobilization of the complex in the solid electrode that turns difficult the formation of the hexacianoferrate film on the electrode surface. Finally, a graphite polyurethane electrode modified with the Cu(II) hexacianoferrate has been used in the voltammetric determination of pyridoxine, based on the diminution of the voltammetric signal of the modifier in the presence of the analyte. In this case a linear dynamic range of 1.08 x 10-6 to 1.07 x 10-5 mol L-1, with a detection limit of 8.78 x 10-7 mol L-1 (3 x S/N). The proposed electrode was used in the determination of pyridoxine in two solid pharmaceutical formulations with recoveries of 98 - 120% without interference of the other substances present in the formulation and no adsorption on the electrode surface.

O mexilhão dourado Limnoperna fortunei é uma espécie exótica que tem causado diversos problemas no ambiente aquático em razão da sua habilidade de formar colônias em estruturas. A espécie adere nas superfícies por filamentos proteicos, causando sérios danos ambientais, sociais e econômicos. A investigação de materiais anti-incrustantes parece ser a alternativa ecológica mais adequada para controle desse molusco. Nesse trabalho foram estudadas as propriedades físico-químicas e a preparação de materiais poliméricos para testes de adesão em campo para cotejar a densidade de incrustação do mexilhão. Foram executados testes de caracterização dos materiais com a finalidade de quantificar parâmetros associados a adesão e a aplicabilidade do material em condições submersas. Foram utilizadas cinco diferentes amostras de poliuretano, desenvolvidos pelo Grupo de Química Analítica e Tecnologia de Polímeros /IQSC-USP, e outros três materiais, aço inoxidável, alumínio e PVC, e então determinados os parâmetros de molhabilidade das proteínas adesivas e as propriedades da superfície. A relação entre a molhabilidade da proteína e os parâmetros químicos de superfície (energia livre de superfície, e seus componentes de dispersão e polaridade) foram examinados com base na tensão superficial crítica, no trabalho de adsorção e no trabalho da adesão. Os resultados sugerem que os materiais que possuem baixa energia livre de superfície têm baixa molhabilidade da proteína. Foi verificado uma relação entre o aumento do componente polar dos materiais quando o trabalho de adsorção diminui para as proteínas, o que significa, que a adsorção das moléculas de proteínas em uma superfície não polar é predominante em relação àquela de uma superfície polar, em solução aquosa. A densidade de mexilhões aderidos nas placas testes, em campo, não mostrou associação com os valores medidos da energia livre de superfície e do componente de dispersão. Contudo, foi observado que as resinas de poliuretano com polaridade na faixa de 1,03-1,14 mJm-2 mostraram-se altamente eficientes, incrustação < 0,5%, como revestimento anti-incrustante. / The gold mussel Limnoperna fortunei is an exotic specie that has been causing many problems in aquatic environment due its aggregation on structures of non polar materials. The specie attaches on surfaces by means of protein filaments causing serious social, economic and environmental damages. The investigation of antifouling materials seems to be a good ecological alternative to control this mussel aggregation. This work has studied the preparation and the physical chemical properties of polymeric materials to be employed in field experiment adhesion tests to quantify the mussel fouling density. Studies were performed for materials characterization in order to quantify parameters associated with adhesion and other materials suitabilities in submerged conditions. Five different polyurethane samples, developed by the Group of Analytic Chemistry and Technology of Polymers /IQSC-USP, and three well-known commercial materials, stainless steel, aluminum and PVC, were used. The proteins wettability and surface properties were evaluated for the aforementioned materials. The relationship between the protein wettability and the surface chemical parameters such as surface free energy, dispersion and polar components were examined based on critical surface tension, work of the adsorption and work of the adhesion. The results suggest that materials with low surface free energy have low protein wettability, i.e., the polar component of materials increases when the work of adsorption decreases for both proteins, which means, the adsorption of native and synthetic protein molecules on a non polar surface is predominant compared to a polar surface, in aqueous solution. The mussel\'s density attachment on test coupons, in field experiment, did not show any correlation with surface free energy and dispersion components values. However, it was observed that polyurethane resins with polarity in the range of 1.03-1.14 mJm-2 showed a good performance, attachment < 0.5%, as anti-fouling coating.

Os cateteres intravasculares são aliados indispensáveis na prática da medicina moderna, particularmente em unidades de terapia intensiva (UTIs). Pelo Cateter Venoso Central (CVC) pacientes que ficam muito tempo internados recebem medicação e alimentação sendo, no entanto, importante fonte de infecção da corrente sanguínea primária. Os CVC\'s de poliuretano podem ter sua superfície modificada pela incorporação de titânio e prata (Ti/Ag) que possuem características antimicrobianas conhecidas desde a antiguidade. A incorporação das nanopartículas de prata sobre o polímero pode ser feita com o uso da radiação ionizante, que também irá esterilizar o material. Assim, este trabalho tem por objetivo utilizar a radiação ionizante para incorporação de nanopartículas de prata em Cateter Venoso Central (CVC) a fim de adquirir propriedades antibactericidas. Para isto utilizou-se o CVC Pellethane 2363-65D, termoplástico de poliuretano elastômero (TPU), óxido de titânio puro, sintetizado pelo processo sol-gel e nanopartículas de prata (NpAg_925). A irradiação para incorporação da prata foi com dose de 25 kGy e com taxa de dose de 1,03 kGy/h em um irradiador \"Gammacel 220\" de 60Co. Posteriormente, os cateteres foram esterelizados com dose de 25 kGy. Pode-se concluir que a incorporação da prata pelo processo de irradiação foi possível e que este processo não afeta a estrutura do polímero, o que é importante para a correta inserção do cateter venoso central no corpo do paciente. Observou-se que o método sol-gel, para deposição do titânio na superfície do CVC, não foi homogênea, dificultando a incorporação da prata que depende do titânio neste processo. Os testes de análise antimicrobiana não indicaram atividade antimicrobiana nos cateteres revestido com titânio e prata, acredita-se que a metodologia escolhida seja inadequada para o tipo de análise. / Intravascular catheters are indispensable allies in the practice of modern medicine, particularly in intensive care units (ICUs). Central Venous Catheter (CVC) patients who are hospitalized for a long time receive medication and feeding, however, being an important source of infection of the primary bloodstream. Polyurethane CVCs may have their surface modified by the incorporation of titanium and silver (Ti/Ag) which have antimicrobial characteristics known from antiquity. The incorporation of the silver nanoparticles on the polymer can be done with the use of ionizing radiation, which will also sterilize the material. Thus, this work aims to use ionizing radiation to incorporate silver nanoparticles in Central Venous Catheter (CVC) in order to acquire antibacterial properties. For this purpose CVC Pellethane 2363-65D, thermoplastic elastomer polyurethane (TPU), pure titanium oxide, synthesized by the sol-gel process and silver nanoparticles (NpAg_925) were used. Irradiation for incorporation of silver was at a dose of 25 kGy and at a dose rate of 1.03 kGy/h in a \"Gammacell 220\" irradiator of 60Co. Subsequently, the catheters were sterilized at a dose of 25 kGy. It can be concluded that the incorporation of silver by the irradiation process was possible and that this process does not affect the structure of the polymer, which is important for the correct insertion of the central venous catheter into the patient\'s body. It was observed that the sol-gel method, for deposition of the titanium on the surface of the CVC, was not homogeneous, making difficult the incorporation of the silver that depends on the titanium in this process. The antimicrobial analysis tests did not indicate antimicrobial activity in catheters coated with titanium and silver, it is believed that the chosen methodology is inadequate for the type of analysis.