Group Transfer Polymerisation (GTP) is a silicon-mediated living polymerisation which can be performed over a wide range of temperatures, allows good control of molecular weight and is a good mechanism for production of block and graft copolymers. A silyl ketene acetal initiator is used to start polymerisation of acrylic or methacrylic monomers which are catalysed by nucleophilic or Lewis acid catalysts in a dry, impurity-free atmosphere. Since its discovery in 1983 by Du Pont, GTP has been ardently researched, although it has not yet been used in an industrial process due to the complicated processing involved and the high cost of initiators.

Híbridos poliuretano-acrílicos foram sintetizados via polimerização em emulsão, utilizando uma dispersão de poliuretano base poliol poliéster como semente para a polimerização dos monômeros acrílicos, no caso, acrilato de butila e ácido metacrílico. As propriedades das dispersões híbridas resultantes foram avaliadas por espalhamento dinâmico de luz, teor de sólidos, pH e potencial Zeta. Os polímeros resultantes da secagem das dispersões aquosas foram caracterizados por cromatografia por exclusão de tamanho, calorimetria exploratória de varredura, análise dinâmico-mecânica, dureza, microscopia ótica do processo de cristalização, microscopia de força atômica, microscopia eletrônica de transmissão. A influência do método de síntese na morfologia dos híbridos foi avaliada. / PU-acrylic hybrids were prepared via emulsion polymerization, using an aqueous polyurethane dispersion as a seed for the acrylic monomers polymerization. Different quantities of acrylic monomers (butyl acrylate and methacrylic acid) were polymerized. The properties of the resulting hybrid dispersions were evaluated through dynamic light scattering, solid content, pH and Zeta potential. The resulting polymers obtained from dried dispersions were characterized via size exclusion chromatography, differential scanning calorimetry, dynamic mechanical analysis, optical microscopy of the crystallization process, atom force microscopy and transmission electron microscopy. The influence of the synthetic method on the morphology of the hybrids was evaluated.

A calorimetria vem a ser uma importante técnica para análise dos processos de polimerização. Dado os benefícios que proporciona seu uso não deve estar limitado somente a grandes empresas, mas também nas micro e pequenas empresas, apoiando-as nas melhorias de seus processos e produtos, motivo este que norteia o desenvolvimento do presente estudo. A validação do sistema proposto baseou-se em comparar seu desempenho frente a um calorímetro tradicional, visando identificar sua capacidade de fornecer informações compatíveis, a um grau de confiança adequado, mesmo com as diferenças existentes. Realizou-se então um ANOVA, que permitiu identificar a existência de outras diferenças importantes entre os sistemas. Porém mesmo frente as diferenças, os resultados quanto à entalpia de reação obtidos em ambos os equipamentos, são considerados estatisticamente similares. As diferenças existentes somente impactaram a variável tempo de pico de reação. Desta forma, foi possível confirmar a capacidade do equipamento proposto em prover resultados confiáveis quando mantidas as mesmas condições de ensaio, porém a um menor custo. No caso de se respeitar as diferenças entre os equipamentos quando da realização dos testes, torna-se possível obter uma eficiência global em torno de 61,21%, quanto a ensaios de polimerização por iniciação térmica. No caso de ensaios envolvendo mecanismos de oxi-redução, pode-se aqui obter um percentual de 40,82%. / Calorimetry comes to be an important technique for the analysis of polymerization processes. It benefits provides the use not only for large companies, but also for micro and small businesses, assisting them to improve processes and qualified products. The validation of the proposed system was based on the comparison of its performance against one traditional calorimeter, to identify their ability to provide consistent, adequate level of confidence, even if the differences occurred. ANOVA was applied to identify the existence of other important differences between the systems. But even forward differences, the results regarding the reaction enthalpy obtained in both devices were considered statistically similar. Differences only reflected the variable reaction peak time. Thus, it was possible to confirm the capability of the proposed equipment to provide reliable results while maintaining the same test conditions, and at expected lower cost. In respect to the differences between the devices while tested, it becomes possible to obtain an overall efficiency at about 61.21% in polymerization by thermal initiation. For assays involving oxidation-reduction mechanisms, it can obtained an overall efficiency at about 40.82%.

Híbridos poliuretano-acrílicos foram sintetizados via polimerização em emulsão, utilizando uma dispersão de poliuretano base poliol poliéster como semente para a polimerização dos monômeros acrílicos, no caso, acrilato de butila e ácido metacrílico. As propriedades das dispersões híbridas resultantes foram avaliadas por espalhamento dinâmico de luz, teor de sólidos, pH e potencial Zeta. Os polímeros resultantes da secagem das dispersões aquosas foram caracterizados por cromatografia por exclusão de tamanho, calorimetria exploratória de varredura, análise dinâmico-mecânica, dureza, microscopia ótica do processo de cristalização, microscopia de força atômica, microscopia eletrônica de transmissão. A influência do método de síntese na morfologia dos híbridos foi avaliada. / PU-acrylic hybrids were prepared via emulsion polymerization, using an aqueous polyurethane dispersion as a seed for the acrylic monomers polymerization. Different quantities of acrylic monomers (butyl acrylate and methacrylic acid) were polymerized. The properties of the resulting hybrid dispersions were evaluated through dynamic light scattering, solid content, pH and Zeta potential. The resulting polymers obtained from dried dispersions were characterized via size exclusion chromatography, differential scanning calorimetry, dynamic mechanical analysis, optical microscopy of the crystallization process, atom force microscopy and transmission electron microscopy. The influence of the synthetic method on the morphology of the hybrids was evaluated.

Híbridos poliuretano-acrílicos foram sintetizados via polimerização em emulsão, utilizando uma dispersão de poliuretano base poliol poliéster como semente para a polimerização dos monômeros acrílicos, no caso, acrilato de butila e ácido metacrílico. As propriedades das dispersões híbridas resultantes foram avaliadas por espalhamento dinâmico de luz, teor de sólidos, pH e potencial Zeta. Os polímeros resultantes da secagem das dispersões aquosas foram caracterizados por cromatografia por exclusão de tamanho, calorimetria exploratória de varredura, análise dinâmico-mecânica, dureza, microscopia ótica do processo de cristalização, microscopia de força atômica, microscopia eletrônica de transmissão. A influência do método de síntese na morfologia dos híbridos foi avaliada. / PU-acrylic hybrids were prepared via emulsion polymerization, using an aqueous polyurethane dispersion as a seed for the acrylic monomers polymerization. Different quantities of acrylic monomers (butyl acrylate and methacrylic acid) were polymerized. The properties of the resulting hybrid dispersions were evaluated through dynamic light scattering, solid content, pH and Zeta potential. The resulting polymers obtained from dried dispersions were characterized via size exclusion chromatography, differential scanning calorimetry, dynamic mechanical analysis, optical microscopy of the crystallization process, atom force microscopy and transmission electron microscopy. The influence of the synthetic method on the morphology of the hybrids was evaluated.

A calorimetria vem a ser uma importante técnica para análise dos processos de polimerização. Dado os benefícios que proporciona seu uso não deve estar limitado somente a grandes empresas, mas também nas micro e pequenas empresas, apoiando-as nas melhorias de seus processos e produtos, motivo este que norteia o desenvolvimento do presente estudo. A validação do sistema proposto baseou-se em comparar seu desempenho frente a um calorímetro tradicional, visando identificar sua capacidade de fornecer informações compatíveis, a um grau de confiança adequado, mesmo com as diferenças existentes. Realizou-se então um ANOVA, que permitiu identificar a existência de outras diferenças importantes entre os sistemas. Porém mesmo frente as diferenças, os resultados quanto à entalpia de reação obtidos em ambos os equipamentos, são considerados estatisticamente similares. As diferenças existentes somente impactaram a variável tempo de pico de reação. Desta forma, foi possível confirmar a capacidade do equipamento proposto em prover resultados confiáveis quando mantidas as mesmas condições de ensaio, porém a um menor custo. No caso de se respeitar as diferenças entre os equipamentos quando da realização dos testes, torna-se possível obter uma eficiência global em torno de 61,21%, quanto a ensaios de polimerização por iniciação térmica. No caso de ensaios envolvendo mecanismos de oxi-redução, pode-se aqui obter um percentual de 40,82%. / Calorimetry comes to be an important technique for the analysis of polymerization processes. It benefits provides the use not only for large companies, but also for micro and small businesses, assisting them to improve processes and qualified products. The validation of the proposed system was based on the comparison of its performance against one traditional calorimeter, to identify their ability to provide consistent, adequate level of confidence, even if the differences occurred. ANOVA was applied to identify the existence of other important differences between the systems. But even forward differences, the results regarding the reaction enthalpy obtained in both devices were considered statistically similar. Differences only reflected the variable reaction peak time. Thus, it was possible to confirm the capability of the proposed equipment to provide reliable results while maintaining the same test conditions, and at expected lower cost. In respect to the differences between the devices while tested, it becomes possible to obtain an overall efficiency at about 61.21% in polymerization by thermal initiation. For assays involving oxidation-reduction mechanisms, it can obtained an overall efficiency at about 40.82%.

En el trabajo con el título "Analytical study of accelerated light ageing and cleaning effects on acrylic and PVAc dispersion paints used in Modern and Contemporary Art" se han empleado diferentes técncias analíticas con el fin de optimizar protocolos experimentales para la caracterización de la estabilidad de acrílicos y acetatos de polivinilo (PVAc) frente a ensayos de envejecimeinto acelerado y tratamientos de limpieza. El estudio de los procesos de degradación causados por la exposición a la luz se ha desarrollado sobre una amplia seria de muestras acrílicas y vinílicas expuestas a dos tipos de envejecimiento acelerado con condiciones de envejecimiento artificail representativas de un envejecimiento natural. La información química y mecánica obtenida por ambos ensayos de envejecimiento acelerado permitió identificar procesos de degradación específicos tales como entrecruzamiento o escisión de cadenas. Las conclusiones obtenidas de forma general apuntan que los acrílicos son materiales más estables que los vinílicos y los estireno-acrílicos. Asimsismo, en este estudio se han aborado los efectos de los tratamientos de limpieza bien de base acuosa, bien con disolventes orgánicos, en las propiedades físico-qúimicas en muestras acrílicas y vinílicas. También se han evaluado otros métodos de limpieza tales como geles o emulsiones. Los resultados indican que los tratamientos acuosos extraen aditivos, afectan la morfología e inducen cambios en las propiedades mecánicas de las muestras. Estos efectos pueden ser reducidos con el uso de sistemas alternativos de limpieza. / De Sousa Ramos Félix Silva, M. (2011). Analytical study of accelerated light ageing and cleaning effects on acrylic and PVAc dispersion paints used in Modern and Contemporary Art [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/13829 / Palancia

Yes / Nanodiamonds (NDs) have been used in various fields of medicine such as drug delivery, tissue regeneration and gene therapy. Although there has been research carried out investigated the potential of these remarkable materials in dentistry, to date no review has been published to summarize the studies conducted. Due to their target cell specificity, small size and fluorescence they have also been found to be usefulness in dentistry. Main applications of NDs in dentistry and medicine include guided tissue regeneration, reinforcement of polymers and drug delivery to treat infections and cancers. Recent research also suggests that NDs can also be used as bioactive or antibacterial dental implant coatings. However, to date, the research conducted on their biocompatibility is limited and inconclusive. Hence, substantially more in vitro and in vivo studies are required to envisage the future of NDs in dentistry. It is hoped that in the next decade these promising materials will find a variety of uses in routine dentistry.

L’implantation de lentilles intraoculaires est le traitement substitutif standard de la cataracte toutes origines confondues. L’implantation est faite à la suite de l’extraction du cristallin par phacoémulsification. Les implants souples, en acrylates hydrophobes, à bord carrés et « 1 pièce » sont recommandés pour prévenir la survenue de complications post-opératoires telles que l’opacification capsulaire postérieure. Cette complication multifactorielle est associée à un défaut de biocompatibilité. L’acte chirurgical, la physiopathologie du patient ainsi que la forme de la lentille intraoculaire modifient l’incidence. Malgré plusieurs mesures préventives, l’incidence n’est pas nulle et la prévalence continue d’augmenter avec le temps. Des cas tardifs d’opacifications surviennent jusqu’à 9 ans après la chirurgie. Un de nos objectifs dans le cadre de ce travail était de relier cette complication tardive au mécanisme de vieillissement des implants intraoculaires. Les résultats obtenus après hydrolyse et photo-oxydation, ont montré une altération des caractéristiques du polymère avec formation de composés néoformés de faibles masses moléculaires, qui diffusent au travers du polymère et migrent vers la surface en fonction de leur polarité et leur masse moléculaire. Il en résulte la création d’un gradient de concentrations de composés hydrophiles en surface et de composés hydrophobes dans les couches inférieures de l’implant. La vitesse du mécanisme de vieillissement est directement liée aux conditions (température, intensité de photo-oxydation). Par ailleurs, nous avons démontré l’existence d’une variation inter et intra lots des caractéristiques physico-chimiques de ces implants. Ces modifications de propriétés de surface constituent une explication à la survenue des complications tardives qui est liées à une modification de la biocompatibilité des implants intraoculaires, après vieillissement / Intraocular lenses are the main treatment for cataract surgery whatever the origin. The implantation is done in the same surgical time as the lens extraction by phacoemulsification. Today, the recommended lenses are foldable acrylic copolymers with square edges and “1-piece”. This design decreases the incidence of adverse events as posterior capsular opacification (POC). This complication is multifactorial and is associated with a poor biocompatibility. The surgery and physiopathology are two others factor that impact the incidence of PCO. Despite many preventive actions, the incidence is not null and prevalence keep on increasing each year after the surgery. The late PCO cases occur until 9 years after the surgery. One of our objectives in the context of this work was to link this late complication to the aging mechanism of intraocular implants. The results obtained after hydrolysis and photo-oxidation have showed the characteristic modifications of the polymer with formation of low molecular weight compounds, which diffuse through the polymer and migrate to the surface, as a function of their polarity and their molecular weight. All these modifications have created concentration gradient. Indeed, the hydrophilic compounds have diffused on the surface and hydrophobic compounds in the implant matrix. The kinetic of the aging process is directly related to the aging conditions applied (temperature, intensity of photo-oxidation). Furthermore, we have demonstrated the existence of the variability between and within batches, of the physicochemical characteristics of these implants. These surface property modifications are an explanation for the occurrence of late complications that is related to a modification of the intraocular lenses biocompatibility after aging.