La mise en place de la démarche PAT (Process Analytical Technology), initiée par la FDA (Food and Drug Administration) s’est développée au cours de ces dernières années, au sein de l’industrie pharmaceutique. Grâce à des contrôles en continu au coeur des procédés de fabrication, elle permet une meilleure compréhension et une maîtrise de la formulation et du procédé, afin d’assurer la qualité finale des médicaments.A travers ce travail, nous avons mis en place un suivi en temps réel, par spectroscopie proche infrarouge, d’une opération d’enrobage suite à l’intégration d’une sonde à l’intérieur d’une turbine d’enrobage. La quantité d’enrobage, déterminée par une simple et rapide pesée mais néanmoins soumise à la variabilité de la masse des comprimés nus, ainsi que l’épaisseur du film, obtenue avec précision par imagerie térahertz ont servi de valeurs de référence pour calibrer l’information spectrale. Dans les deux cas, ces deux attributs qualité critiques ont été prédits avec de faibles erreurs de prédiction, qui se sont révélées être similaires. Par ailleurs, la prédiction en temps réel des propriétés de dissolution de comprimés prêts à être libérés, à partir de spectres acquis in-line, a permis de déterminer l’arrêt optimal de l’opération d’enrobage.Suite à un enrobage réalisé à partir d’une dispersion aqueuse de polymère une étape supplémentaire de traitement thermique ou curing est généralement nécessaire afin de stabiliser le film d’enrobage. Un travail de caractérisation mené à partir de techniques innovantes a permis d’apporter un nouvel éclairage sur la compréhension des phénomènes impliqués dans la formation du film au cours du curing. La caractérisation approfondie de la structure d’enrobage de comprimés soumis à un curing en turbine (conditions dynamiques) a mis en évidence la diminution de la porosité, couplée à l’évaporation de l’eau et à une meilleure organisation des chaînes de polymère au cours du curing. L’étude de comprimés soumis à un curing de référence en étuve durant 24 h (conditions statiques) a confirmé l’obtention d’un film stable après 4 h de curing dynamique. De nouveaux phénomènes, indépendants du curing, liés à la cristallisation et à la migration de l’alcool cétylique, couplée à la migration du lauryl sulfate de sodium, au sein de la couche d’enrobage ont été détectés au cours de la conservation des comprimés enrobés. / Implementation of PAT (Process Analytical Technology) approach has recently been promoted by the FDA (Food and Drug Administration) within the pharmaceutical industry. A desired goal of the PAT framework is to enhance understanding and control of the manufacturing process through timely measurements, during processing, to ensure final product quality. Real-time monitoring of a coating operation was performed from in-line Near Infrared (NIR) measurements inside a pan coater. Mass of coating materials, determined by simple and fast weighing but depending on core tablet weight uniformity, and film coating thickness, obtained from accurate and non-destructive Terahertz Pulsed Imaging (TPI) measurements, were used as reference values to calibrate NIR spectral information. In both cases, these two critical quality attributes were predicted with low predictive errors, which were found to be similar. In addition, real-time predictions of drug release from cured tablets were carried out by in-line NIR measurements. The coating operation was successfully stopped when desired dissolution criteria were achieved. A post-coating thermal treatment, known as curing, is generally required to stabilize film coating from aqueous polymer dispersion. Innovative techniques were jointly used to elucidate the underlying mechanisms of film formation along the curing process. This study provided a new insight into the tablet coating structure, highlighting a reduced internal coating porosity, a decrease in water content and showing a better structural rearrangement of polymer chains, with dynamic curing. All investigated techniques confirmed that a stabilized state was reached after a 4 h dynamic curing in comparison with a reference curing carried out in an oven for 24 h. Interestingly even prior to curing, new findings were pointed out, during coated tablets storage, related to the crystallisation and the upward migration of cetyl alcohol, coupled to the downward migration of sodium lauryl sulfate within the coating layer.

The concept of sustainable use of materials defines as utilizing raw material as less aspossible and introducing less toxic substances to the environment as well. Smartmaterials are one route for sustainability, as they have optimal performance in relation tomaterial composition. New technologies can be developed by using smart materials. Onearea is the development of smart textiles, meaning the incorporation of electronicfunctions in textiles. These functions can be used for human protection or monitoring ofhealth.Conductivity is a key factor in smart textiles. The aim of this report is to identifyelectrically conductivity of textile fibres in conjunction with conductive polymer(polyaniline). By applying conductive polymer (polyaniline ink) on textiles fabric andfibres it is possible to obtain conductive textile products. This project focuses on thedevelopment of conductive fibres by coating of an individual fibre or a few differenttypes of fabric with conductive polymer polyaniline dispersion in water and toluene assolvent. Various situations have been taken into consideration and investigated fordifferent concentration to different times of coating and deposit thickness. Performanceon resistivity calculation led to find optimum concentration and coating numbers anddeposit thickness. Based on the inventory, a qualitative resistivity analysis is carried outfor the purpose of identifying which combination of concentration and times of coating inthe case of woven types fibre or coating thickness in the case of non woven types offabrics as well as the types of fabrics would provide the better conductivity properties in the textile fibres and fabrics.

Conducting polymer coating is the new developing area in the field of advanced textiles. In this project the rheological behaviour of paste containing conducting polymer was studied during formulation to coating application. The literature study is done by keeping all the contents of project in mind and a wide area of conductive polymer, coating methods, binder system and rheology modifier is covered. The rheological behaviour of different fluid containing newtanion and non-newtanion behaviour is discussed for better understanding of the project working. Polyester fabric was coated by knife coating method. In paste formulation, the chemicals used were polyurethane binder with two HEUR based rheology modifiers. A lot of experiments were performed to determine the right amount of rheology modifier alone or in combination for paste formulation and coating application and interesting findings were observed during the experimental work which had been justified in results and analysis. After application, the coated fabric was checked for resistivity. / Program: Magisterutbildning i textilteknologi

This final thesis goal has been to try and develop a titanium dioxide coating for water purification. The coating should be used in a manufacturing industry on textiles. Water purification is achieved through photocatalysis with titanium dioxide and UV-radiation, where hydroxyl radicals form through oxidation. The kind of textile fiber chosen for the substrates is a polyester fiber. The substrates have been developed in several different shapes. Two different knitted patterns was developed, one flat patterned and one wavy patterned. Another kind of substrate was a spacer-type and there was also a substrate made from a PET-bottle. The different substrates were chosen to compare the different coatings effect on different surfaces and the different coatings were developed from two types of titanium dioxide. The coated substrates have been analyzed for hydroxyl radical generating properties. By testing a sample of water with titanium dioxide against a sample with water that had no additives, it was shown that titanium dioxide generates more hydroxyl radicals. The results of the work showed that the recipe containing 3 % titanium dioxide and 3 % acrylic binder showed good properties for water purification. In addition, the results showed a stronger effect for the wavy patterned substrate then the flat patterned, which is an interesting result that should be researched further in the future. / Program: Textilingenjörsutbildningen

O tratamento de sementes pode ser uma importante técnica para o fornecimento de micronutrientes na cultura do milho (Zea mays L.), sendo capaz de promover um melhor estabelecimento da cultura no campo. Solos contendo níveis insuficientes de zinco e de cobre para as plantas são frequentes em grande parte das regiões agrícolas do Brasil e do mundo. Deste modo, o fornecimento destes elementos via sementes pode ser uma alternativa viável e eficaz para produtores de milho. Este trabalho teve como objetivo avaliar diferentes tratamentos de sementes de milho contendo Zn e Cu, considerando aspectos relacionados à qualidade fisiológica das sementes e à eficiência nutricional. Para tal, foram utilizados quatro lotes do híbrido 2B688Hx, apresentando diferenças quanto ao tamanho e vigor das sementes. Os tratamentos foram compostos por diferentes dosagens e combinações de suspensões líquidas contendo óxido de Zn e carbonato de Cu, fornecidos juntos ou separadamente. Os lotes foram avaliados pelo teor de água das sementes, germinação e teste de frio em cinco épocas: 0, 30, 60, 180 e 360 dias. Nas três primeiras épocas, também foram realizados os testes de emergência de plântulas, velocidade de emergência de plântulas e análises do crescimento de raiz por meio do software SVIS®. O desenvolvimento inicial das plantas foi avaliado pela altura, área foliar e massa seca de raiz e de parte aérea. Os dados de massa seca associados aos teores de Zn e de Cu nos tecidos permitiram calcular as eficiências de absorção, transporte e utilização dos mesmos. A qualidade fisiológica de sementes de milho tratadas com Zn e Cu, isoladamente ou associados, não é afetada ao longo de doze meses de armazenamento; por outro lado, o Cu utilizado isoladamente causa fitotoxicidade quando a avaliação é realizada tendo o papel como substrato, afetando principalmente o desenvolvimento radicular das plântulas. O tratamento de sementes com zinco e cobre se constitui em alternativa viável e eficaz para o fornecimento destes elementos para as plantas de milho. / Seed treatment is a potential tool for supplying micronutrients on maize crop (Zea mays L.), enabling a better plant stand establishment in the field. Soils presenting insufficient levels of zinc and copper to plants are common in various agricultural regions throughout Brazil and the world. Thus, the supply of such elements via seeds can be viable and effective for maize crop. This study aimed to evaluate different maize seed treatments containing Zn and Cu, related to the effects on seeds physiological quality and nutritional efficiency. Thus, four seeds lots of the corn hybrid 2B688Hx, differing in size and vigor, were used for this study. The treatments were composed of liquid suspensions containing Zn oxide and Cu carbonate, applied together or separately at different dosages. The lots were evaluated by seed moisture, germination and cold test in five periods: 0, 30, 60, 180 and 360 days. Seedling emergence, seedling emergence speed and image analysis of root growth (software SVIS®) were also performed in the first three periods. The plants development was assessed by height, leaf area and dry weight of roots and shoots. The efficiencies of absorption, transport and utilization were calculated with the data of seedlings dry weight and tissues content of Zn and Cu. The physiological quality of maize seeds is not affected by the treatments containing Zn and Cu, together or separated, during the twelve-month storage period; on the other hand, the treatments containing only Cu caused phytotoxicity on paper-based tests, affecting mainly the seedlings root development. Seed treatment with zinc and copper is a viable and effective approach for supplying these elements to maize plants.

Com o desenvolvimento da nanociência e da nanotecnologia, as nanopartículas magnéticas vêm sendo cada vez mais gerado interesse devido as inúmeras possíveis aplicações na área de catálise, diagnóstico, pigmentos, sensores, etc. Atualmente, as nanopartículas com potencialidade de aplicação em biomedicina que pode se destacar os as ferritas magnéticas os quais apresentam comportamento superparamagnético a temperatura ambiente. Além dos ligantes funcionais, as nanopartículas magnéticas são geralmente recobertas com polímeros orgânicos ou inorgânicos, destacando-se a sílica, nessa última classe. O sistemas as nanopartículas magnéticas recobertas com sílica formando um sistema casca-caroço, possibilita que o núcleo magnético se mantenha protegido por uma camada polimérica que pode conter grupos funcionais ativos, formando hidridos orgânicos-inorgânicos que devido a sua propriedade hidrofóbica ou hidrofílica dependendo da natureza do ligante de modificação de superfície. Este trabalho foi desenvolvido com intuito de obter nanopartículas magnéticas de ferrita MFe2O4, com (M= Fe, Co, Ni e Cu) com controle de tamanho, forma, composição química e estrutural, dos quais foram sintetizados pelo método de decomposição térmica utilizando diferente precursores metálicos para adequação das melhores condições de síntese. As ferritas magnéticas foram recobrimento com sílica, modificando da superfície da partícula e possibilitando caráter hidrofílico ao sistema casca-caroço, apresentando uma melhor estabilidade coloidal em dispersão aquosa devido a presença de grupos silanois na superfície, bem como uma recobrimento uniforma com apenas um núcleo magnético sem formação de aglomerados. A funcionalização com o grupo o trietoxivinilsilano, através de reações de condensação via catálise básica ou ácida, formou uma rede polimérica Si-O-Si, sendo que a presença do grupo vinil (-CH=CH2) livre na a superfície do sistema casca-caroço foi evidenciado através da técnica de FTIR. Portanto foi possível a obtenção de um sistema hibrido orgânico-inorgânico com a superfície contendo grupo que podem ser reativos, abrindo a possibilidade da utilização deste material para futuros testes de aplicações como sensor multifuncional. / In recent decades the development of nanoscience and nanotechnology, magnetic nanoparticles have been increasingly generated interest due to the numerous possible applications in the field of catalysis, diagnosis, pigments, sensors, etc. Currently, the nanoparticles with potential of application in biomedicine that can stand out the magnetic ferrites which have superparamagnetic behavior at room temperature. In addition to the functional binders, magnetic nanoparticles are generally coated with organic or inorganic polymers, especially silica in the latter class. The magnetic nanoparticle systems covered with silica forming a shell-core system allow the magnetic core to remain protected by a polymeric layer that may contain active functional groups, forming organic-inorganic hydrides that due to its hydrophobic or hydrophilic property depending on the nature of the surface modifying binder. This work was developed to obtain magnetic nanoparticles of MFe2O4 ferrite, with (M = Fe, Co, Ni and Cu) control of size, shape, chemical and structural composition, of which were synthesized by the thermal decomposition method using different precursors to suit the best conditions of synthesis. The magnetic ferrites were coated with silica, modifying the surface of the particle and allowing a hydrophilic character to the shell-core system, presenting a better colloidal stability in aqueous dispersion due to the presence of silane groups on the surface, as well as a uniform coating with only one magnetic core without formation of agglomerates. The functionalization with the triethoxyvinylsilane group, through condensation reactions via basic or acid catalysis, formed a Si-O-Si polymer network, and the presence of the free vinyl group (-CH=CH2) on the shell surface was observed by FTIR technique. Therefore, it was possible to obtain an organic-inorganic hybrid system with the surface containing the reactive group, opening the possibility of using this material for tests of future applications as multifunctional sensor.

O carbeto de silício (SiC) é um material que apresenta baixa expansão térmica, altas resistências mecânica e ao choque térmico e alta condutividade térmica. Em razão disto é empregado na confecção de mobília de fornos de sinterização. O SiC no entanto sofre degradação a altas temperaturas quando submetido a atmosferas agressivas. A utilização de recobrimentos protetores evita a exposição direta da superfície do material à atmosfera dos fornos; a mulita pode ser um recobrimento protetor apropriado em razão de sua alta estabilidade em temperaturas elevadas e seu coeficiente de expansão térmica compatível com o do SiC (4x10-6/°C e 5,3x10-6/°C, respectivamente). No presente trabalho foi estudada a obtenção de recobrimento de mulita, para refratário de SiC, a partir da utilização de polímero precursor cerâmico e alumínio particulado. Foram preparadas composições com 10, 20, 30 e 50% (vol.) de alumínio adicionado ao polímero, sendo utilizados pós de alumínio de diferentes distribuições de tamanhos de partículas. As composições foram submetidas a diversos ciclos térmicos para determinação da condição mais adequada à obtenção de alto teor de mulita. A composição que apresentou melhor resultado foi a contendo 20% do pó de Al de menor tamanho de partículas. A partir desta, foi preparada e aplicada suspensão para ser aplicada sobre o refratário de SiC. A suspensão aplicada, após seca, reticulada e tratada termicamente a 1580°C, originou um recobrimento de mulita. Foram realizados ciclos de choque térmico em amostras com e sem recobrimento para comparação, num total de 26 ciclos. As condições foram 600°C/30 min. seguida de resfriamento ao ar até a temperatura ambiente. Após cada choque térmico, as amostras foram caracterizadas por microscopia óptica e eletrônica e determinado o módulo de elasticidade. Os recobrimentos apresentaram boa adesão e não foram detectados danos significativos após os choques térmicos. / Silicon carbide (SiC) presents low thermal expansion, high strength and thermal conductivity. For this reason it is used as kiln furniture for materials sintering. On the other hand, SiC degrades at high temperature under aggressive atmosphere. The use of protective coatings can avoid the right exposition of SiC surface to the furnace atmosphere. Mullite can be a suitable material as protective coating because of its high corrosion resistance and thermal expansion coefficient matching that of SiC (4,7 x10-6/°C e 5,3 x10-6/°C, respectively). In the present work a mullite coating obtained from ceramic precursor polymer and aluminium powder was studied to be applied over SiC refractories. Compositions were prepared with 10, 20, 30 and 50% (vol.) of aluminium powder added to the polymer. They were used aluminium powders with different distributions sizes These compositions were heat treated at different thermal cycles to determine a suitable condition to obtain a high mullite content. The composition with 20% of the smaller particle size Al powder was selected and used to be applied as a suspension over SiC refractory. The applied suspension, after dried, crosslinked and heat treated, formed a mullite coating over SiC refractory. Cycles of thermal shock were performed in coated and uncoated SiC samples to compare each other. They were carried out 26 cycles of thermal shock, in the following conditions: 600°C/30 min. and air cooling to room temperature. After each thermal shock, samples were analised by mean of optical and electron microscopy, elastic modulus was also determined. After thermal shock cycles the coating presented good adhesion and no significant damage were observed.

Residual stresses are generally considered to be the driving forces for the failure of APS TBCs. In this thesis, the residual stress distribution as a function of depth in APS TBC has been measured by synchrotron XRD and explained by image based modelling based on the microstructure detailed studied by SEM and CT. The residual stress/ strain distribution as a function of depth was measured by synchrotron XRD in transmission and reflection geometry. The residual stress/ strain values were analysed using full pattern Rietveld refinement, the sin square psi method and XRD2 method. For the reflection geometry, a new method was developed to deconvolute the residual stress value in each depth from the measured averaged values. Two types of residual stress/strain distribution were observed. The first kind of residual stress was found to be compressive and followed a non-linear trend, which increased from the surface to the interface, decreased slightly and increased again to the interface. This trend showed a jump feature near the interface. The second kind of residual stress distribution possessed two jump features: one near the interface similar to the first kind and another jump feature near the sample surface. The residual stress in both beta and gama phase in the bond coat were also investigated which showed a tensile stress state. The stress trend predicted by our analytical model followed a linear relationship. Comparing this with the first kind of residual stress distribution, two main differences were shown. Firstly the jump feature near the interface and secondly the much larger overall stress gradient. The 3D and 2D microstructure of the sample with the first kind of residual stress distribution was observed by X-ray CT and SEM. The effect of pores, inter-splat cracks and the rumpling interface on the residual stress distribution was investigated by image based modelling. It was proved that the pores and the inter-splat cracks had no large influence on the stress distribution and the jump feature near the interface was a result of the rumpling interface. The much larger stress gradient observed in the measured residual stress distribution was an indication of the stress relaxation in the coating which was proved by a specially designed mechanical test. To explain the jump feature near the sample surface in the second kind of stress distribution. 3D microstructures of the measured samples were observed using X-ray CT. The effect of vertical and the side cracks on the stress distribution were investigated by image based modelling. It was found that the vertical crack had no large influence on the residual stress distribution and the jump feature in the stress trend near the surface could be attributed to the side crack. The effect of other kinds of cracks that were not directly observed in our samples, such as middle or through side cracks, were also investigated. These results were used to develop a semi-destructive method to determine the existence and distribution of cracks in APS TBC.

Buried pipelines are vulnerable to the threat of corrosion. Hence, they are normally coated with a protective coating to isolate the metal substrate from the surrounding environment with the addition of CP current being applied to the pipeline surface to halt any corrosion activity that might be taking place. With time, this barrier will deteriorate which could potentially lead to corrosion of the pipe. The External Corrosion Direct Assessment (ECDA) methodology was developed with the intention of upholding the structural integrity of pipelines. Above ground indirect inspection techniques such as the DCVG which is an essential part of an ECDA, is commonly used to determine coating defect locations and measure the defect's severity. This is followed by excavation of the identified location for further examination on the extent of pipeline damage. Any coating or corrosion defect found at this stage is repaired and remediated. The location of such excavations is determined by the measurements obtained from the DCVG examination in the form of %IR and subjective inputs from experts which bases their justification on the environment and the physical characteristics of the pipeline. Whilst this seems to be a straight forward process, the factors that comes into play which gave rise to the initial %IR is not fully understood. The lack of understanding with the additional subjective inputs from the assessors has led to unnecessary excavations being conducted which has put tremendous financial strain on pipeline operators. Additionally, the threat of undiscovered defects due to the erroneous nature of the current method has the potential to severely compromise the pipeline's safe continual operation. Accurately predicting the coating defect size (TCDA) and interpretation of the indication signal (%IR) from an ECDA is important for pipeline operators to promote safety while keeping operating cost at a minimum. Furthermore, with better estimates, the uncertainty from the DCVG indication is reduced and the decisions made on the locations of excavation is better informed. However, ensuring the accuracy of these estimates does not come without challenges. These challenges include (1) the need of proper methods for large data analysis from indirect assessment and (2) uncertainty about the probability distribution of quantities. Standard mean regression models e.g. the OLS, were used but fail to take the skewness of the distributions involved into account. The aim of this thesis is thus, to come up with statistical models to better predict TCDA and to interpret the %IR from the indirect assessment of an ECDA more precisely. The pipeline data used for the analyses is based on a recent ECDA project conducted by TWI Ltd. for the Middle Eastern Oil Company (MEOC). To address the challenges highlighted above, Quantile Regression (QR) was used to comprehensively characterise the underlying distribution of the dependent variable. This can be effective for example, when determining the different effect of contributing variables towards different sizes of TCDA (different quantiles). Another useful advantage is that the technique is robust to outliers due to its reliance on absolute errors. With the traditional mean regression, the effect of contributing variables towards other quantiles of the dependent variable is ignored. Furthermore, the OLS involves the squaring of errors which makes it less robust to outliers. Other forms of QR such as the Bayesian Quantile Regression (BQR) which has the advantage of supplementing future inspection projects with prior data and the Logistic Quantile Regression (LQR) which ensures the prediction of the dependent variable is within its specified bounds was applied to the MEOC dataset. The novelty of research lies in the approaches (methods) taken by the author in producing the models highlighted above. The summary of such novelty includes: * The use of non-linear Quantile Regression (QR) with interacting variables for TCDA prediction. * The application of a regularisation procedure (LASSO) for the generalisation of the TCDA prediction model.* The usage of the Bayesian Quantile Regression (BQR) technique to estimate the %IR and TCDA. * The use of Logistic Regression as a guideline towards the probability of excavation * And finally, the use of Logistic Quantile Regression (LQR) in ensuring the predicted values are within bounds for the prediction of the %IR and POPD. Novel findings from this thesis includes: * Some degree of relationship between the DCVG technique (%IR readings) and corrosion dimension. The results of the relationship between TCDA and POPD highlights a negative trend which further supports the idea that %IR has some relation to corrosion. * Based on the findings from Chapter 4, 5 and 6 suggests that corrosion activity rate is more prominent than the growth of TCDA at its median depth. It is therefore suggested that for this set of pipelines (those belonging to MEOC) repair of coating defects should be done before the coating defect has reached its median size. To the best of the Author's knowledge, the process of employing such approaches has never been applied before towards any ECDA data. The findings from this thesis also shed some light into the stochastic nature of the evolution of corrosion pits. This was not known before and is only made possible by the usage of the approaches highlighted above. The resulting models are also of novelty since no previous model has ever been developed based on the said methods. The contribution to knowledge from this research is therefore the greater understanding of relationship between variables stated above (TCDA, %IR and POPD). With this new knowledge, one has the potential to better prioritise location of excavation and better interpret DCVG indications. With the availability of ECDA data, it is also possible to predict the magnitude of corrosion activity by using the models developed in this thesis. Furthermore, the knowledge gained here has the potential to translate into cost saving measures for pipeline operators while ensuring safety is properly addressed.

Les silicones acrylates photoréticulés sont largement utilisés dans les revêtements de divers matériaux. Leur production nécessite l’utilisation d’un photoamorceur considéré comme potentiellement reprotoxique, ce qui impose aux producteurs de revêtements silicones d’imaginer des formulations alternatives. L’augmentation de la consommation de ce type de revêtements amène à s’interroger sur leur devenir au cours et en fin de vie dans les filières de traitement des déchets et sur l’influence du changement de photoamorceur sur le comportement environnemental des revêtements. Ce domaine de recherche demande la mise en place d’une méthodologie spécifique, alliant des expériences de dégradation physico-chimiques et biologiques. Deux types de revêtements photoréticulés par deux photoamorceurs différents : le Darocur 1173 et Darocur 1173 modifié (nouveau photoamorceur) font l’objet de cette étude. L’exposition des revêtements silicones aux UV a montré que ces composés sont facilement dégradables et sensibles au photovieillissement. L’enduction silicone augmente, elle, la photosensibilité des films revêtus. Dans un contexte de fin de vie, les essais réalisés sur la matrice silicone ont permis de mettre en évidence une légère hydrolyse chimique des chaines siloxanes, non biodégradables aussi bien en aérobiose qu’en anaérobiose mais dont la présence n’inhibe pas l’activité microbienne. Les photoamorceurs testés présentent des comportements totalement différents face à la lixiviation et à la dégradation biologique: ainsi, le Darocur 1173 est très mobile en phase aqueuse, facilement assimilable par les microorganismes comme source primaire de carbone en conditions aérobies contrairement au Darocur 1173 modifié. Qu’il y ait eu biodégradation ou non, la structure de la communauté microbienne est influencée différemment suivant le photoamorceur utilisé. L’utilisation du Darocur 1173 modifié permet de diminuer le risque de migration et sa toxicité potentielle dans les revêtements silicones. La démarche mise en œuvre apporte de nombreuses informations quant aux impacts environnementaux et pourra servir d’exemple pour l’étude d’autres déchets silicones. / Photocrosslinked silicones acrylates are widely used in coatings of various materials. Their production requires the use of photoinitiator considered as potentially reprotoxic, which requires producers of silicone coatings to devise alternative formulations. Consumption increase of this type of coatings raises questions about their fate during and at their end-of-life in waste treatment channels and the influence of photoinitiator change on the environmental behavior of the coatings. This research area needs the use of a specific methodology, combining physico-chemical and biological degradation experiments. Two types of coatings photocrosslinked by two different photoinitiators: Darocur 1173 and modified Darocur 1173 (new photoinitiator) are the subject of this study. UV exposure of silicone coatings showed that these materials are easily degradable and sensitive to photoageing. The silicone coating increases the photosensitivity of coated films. At the end-of-life stage, performed experiments on silicone coatings revealed a slight chemical hydrolysis of the non-biodegradable siloxane chains, both under aerobic and anaerobic conditions. However, these materials does not inhibit the microbial activity. The tested photoinitiators have totally different behavior regarding the leaching and biological degradation: Darocur 1173 is very mobile in aqueous phase, easily assimilated by microorganisms as a primary sole of carbon under aerobic conditions in contrast to modified Darocur 1173. Whether there has been biodegradation or not, the structure of microbial communities is influenced differently depending on the used photoinitiator. Modified Darocur 1173 reduces the risk of migration and its potential toxicity in silicone coatings. The implemented approach brings a lot of information about the environmental impacts and can serve as an example for the study of other silicone waste.