Cette thèse porte sur la dégradation photochimique des résines naturelles utilisées dans la fabrication de vernis à tableaux. Différentes résines ont été choisies pour notre étude : la sandaraque, le copal de Manille, la colophane, le mastic et la dammar. Des vernis à tableaux ont été fabriqués à partir de ces résines dissoutes dans de l’alcool, de l’huile ou de l’essence de térébenthine selon d’anciennes recettes. Ils ont par la suite été vieillis artificiellement en enceinte d’irradiation. L’étude en spectrométrie infrarouge a permis de montrer qu’une identification du type de résine était possible par cette technique. De nombreuses bandes d’absorption spécifiques ont été mises en évidence mais tendent à disparaître tout au long du photovieillissement. Néanmoins, la bande des CH (2850-3050 cm-1) permet de séparer les résines diterpéniques et triterpéniques, et l’analyse en composante principale des données permet d’affiner les identifications. Les analyses en CPG-SM nous ont permis d’identifier la plupart des molécules présentes au sein de nos vernis grâce à l’étude des fragmentations en spectrométrie de masse. Dans ce cadre, une étude poussée du comportement des molécules a été effectuée, notamment par des expériences en SM/SM. Quatre phénomènes de photodégradation ont été observés : l’isomérisation, la scission, l’hydroxylation et l’oxydation de type Norrish I des terpènes présents. Le choix du solvant utilisé dans la fabrication du vernis influence fortement la composition du vernis et sa cinétique de dégradation, en particulier dans le cas d’un vernis à l’huile. La présence d’une vitre devant le vernis a également une influence, plus ou moins importante, sur les mécanismes photochimiques. Des vernis anciens récupérés auprès de conservateurs-restaurateurs ont été identifiés grâce à la base de données effectuée à partir de nos expérimentations, validant notre méthodologie. Les premiers essais de polymères à empreinte moléculaire ont également été effectués donnant des résultats encourageants pour l’étude de mélanges de terpènes / This thesis presents a study on the photochemical degradation of natural resins used in the manufacture of painting varnishes. Following the literature, five resins were chosen for our experiments: sandarac, Manila copal, colophony, mastic and dammar. Varnishes were made from those resins dissolved in alcohol, oil or turpentine spirit, as found in old recipes. They were then photo-aged by irradiation under artificial light. The study by infrared spectrometry enabled the identification of the type of resin. Although various specific absorption bands were highlighted, they tend to disappear all along the photoageing process. Nevertheless, the C-H band situated between 2850 and 3050 cm-1 allows to separate diterpenic and triterpenic resins and the analysis by principal components can help the identification. Thanks to the study by GC-MS we could identify most of the molecules present in our varnishes by developing the fragmentation study in mass spectrometry. An advanced study of the molecules behaviour was done, especially by MS/MS experiments. Four photo-degradation reactions were observed: isomerisation, cleavage, hydroxylation and Norrish I oxidation of the terpenoids. The choice of the solvent used in the varnish can affect its composition and degradation kinetic, mostly for oil varnishes. Besides, a window pane placed before the varnish will influence the photochemical mechanisms. Ancient varnishes collected by conservator-restorers were analysed and identified thanks to the database elaborated from our results, validating our methodology. The first experiments of molecularly imprinted polymers were carried out with some encouraging results for the analysis of mixed terpenoids

In der Konservierungsforschung werden unterschiedlichste Materialien analysiert und auf ihre Stabilität hin geprüft, um gezielte Konservierungs- oder Restaurierungsmassnahmen durchzuführen und deren Nachhaltigkeit besser einschätzen zu können. Die Chemilumineszenz - im Folgenden kurz CL - ist ein Phänomen, bei dem ein Elektron aus einem energetisch höher gelegenen Orbital in einen tiefer liegenden Zustand relaxiert und dabei seine Energie in Form von Photonen abgibt. Der angeregte Zustand wird durch eine chemische Reaktion verursacht. Dieser Vorgang ist sehr spezifisch und tritt u.a. bei Oxidationsreaktionen auf. Durch Rekombination zweier Peroxide wird z.B. eine angeregte Carbonylverbindung erzeugt, die ihre Energie als Licht emittiert. Dieser Zusammenhang zwischen der Oxidation organischer Substanzen und die Emission von Photonen bedingt die hier zentral gestellte Frage, ob die Chemilumineszenz als Methode zur Charakterisierung von Materialien, die in der Konservierungsforschung relevant sind, eingesetzt werden kann. Innerhalb einer Forschungskooperation zwischen Departementen der Berner Fachhochschule BFH konnte ein Chemilumineszenz-Messgerät konstruiert, modifiziert und für diese Arbeit eingesetzt werden. In der Arbeit wurde ein standardisiertes Messverfahren an verschiedenen Substanzen, wie z.B. Adamantylidenadamantan-1.2-dioxetan geprüft und die verschiedenen Einflüsse auf das Chemilumineszenz-Signal untersucht. Dabei konnten für das Messprinzip wichtige Daten, wie z.B. Präzision, Nachweis- und Bestimmungsgrenze erhoben werden. Anhand der Stabilität von Dammar, einem Triterpen-Naturharz, konnte das Verfahren innerhalb der Arbeit, an einem komplexen Beispiel aus der Konservierungsforschung experimentell erprobt werden. Dabei wurden publizierte Resultate zum Oxidationsverhalten von Dammarharz teilweise verifiziert. Durch das spezifische Signal konnten die thermisch initiierten Reaktionen bei inerten und oxidativen Gas-Atmosphären dokumentiert werden. Die Ergebnisse wurden mit etablierten Methoden, wie z.B. DSC, TGA und ESR- Spektroskopie verglichen und Konsistenzen zu den Signalen erfasst. Der in der Literatur diskutierte Einfluss von Stabilisatoren auf Dammarharz-Filme wurde an ungealterten und künstlich gealterten Proben mit der Chemilumineszenz untersucht. Dabei konnten ebenfalls in der Literatur empfohlene Formulierungen und Wirkungen bestimmter synergetischer Mischungen nachgewiesen und bestätigt werden. Aus den ermittelten Daten der CL-Messungen liessen sich in einem Ausblick kinetische Berechnungen zu Aktivierungsparametern erstellen. Die ermittelten Parameter wurden zur Prognose von Reaktionsverläufen bei unterschiedlich simulierten Temperaturprofilen genutzt und machten eine Vorhersage zur Lebensdauer der Materialien möglich. Neben der hohen Leistungsfähigkeit der Methode zeigte sich v.a. das hohe Potential der ermittelten Messdaten, v.a. in Bezug auf die Anwendung in der Modellfreien Kinetik. Neben diesen Möglichkeiten wurden aber auch die Grenzen der Methode aufgezeigt. Diese sind einerseits durch die Besonderheit des Signals gegeben, welches mechanistisch bis heute noch nicht vollständig aufgeklärt ist, andererseits liegen sie bei der Weiterverarbeitung der Messdaten durch thermokinetische Software. Hier wird deutlich, dass die Qualität der Berechnungen zu Reaktionsverläufen nur so gut ist, wie die zuvor erhobenen Daten und, dass erstellte Prognosen zur Stabilität eines Materials lediglich eine Vorstellung vermitteln können. / During conservation studies different materials are analysed and tested for their solidity in order to be able to carry out precise conservation and restoration measures and to be able to assess their sustainability. Chemiluminescence is a phenomenon in which an electron is relaxed from an energetically higher orbital into a lower situated condition while simultaneously releasing energy in the shape of photons. As a consequence the stimulated state is caused by a chemical reaction. This process is very specific and occurs during an oxidation reaction among other things. Through the recombination of two peroxides for example a stimulated carbonyl compound is generated which emits its energy as light. This connection between the oxidation of organic substances and the emission of photons determines the main question, whether chemiluminescence can be used as a method for characterisation of materials which are relevant to the research of conservation. As a result of a research project between departments of the Bern University of Applied Sciences BFH it was possible to construct a chemiluminescence measuring device and modify it in a way that it could be used for this work. Within this experiment a standardised method of measurement was tested on different substances, for example adamantylidenadamantan-1.2-dioxetan, and the different impacts on the chemiluminescence-signal investigated. Through this process important facts were determined for the concept of measurement, for example precision, proof- and definition perimeters. Based on the solidity of dammar, a triterpene resin, the method could be experimentally verified within the test using a complex example from conservation research. Within that process published results about the oxidation properties of dammar resin were verified. Due to the specific signal, the thermally initiated responses in inert as well as oxidative gas atmospheres could be documented. The results were compared with established methods like DSC, TGA and ESR spectroscopy and the consistencies to the signals logged. The already much discussed influence of stabilisers on dammar resin was tested on nonaged and artificially aged specimens using chemiluminescence. Through these previously suggested formulations, effects of certain synergistic composites were detected and confirmed. Using the data from the chemiluminescence measurements kinetic calculations about activation parameters were compiled. The identified parameters were used for the prognosis of the course of reactions during differently simulated temperature profiles, making a prediction of the materials’ life span possible. Through these results not only the high performance ability of the method became apparent but also the potential of the determined measurement data, mainly in connection with the application within the model-free kinetic. However, alongside these possibilities limitations of the method were revealed. These are partly caused by the characteristics of the signal which has yet to be mechanistically fully clarified. Simultaneously, further processing of the measurement data via thermokinetic software makes clear that the quality of the calculations of the reaction process is only as good as the quality of the initial data. This suggests the prognoses about the stability of the material only conveys a concept of their qualities.

Made available in DSpace on 2016-04-28T14:16:20Z (GMT). No. of bitstreams: 1 Adriana Quilici Barreto Cianciarulo.pdf: 1562918 bytes, checksum: 9aff2869a45eef833b4809bfdc83be16 (MD5) Previous issue date: 2014-12-10 / Conselho Nacional de Desenvolvimento Científico e Tecnológico / Based on the history of science, this research aimed to discover the materials used as pigment and the specificities of colonial Brazilian artistic production through literature related to decorative arts of the period. To achieve some of those materials we‟ve referred the treatises on painting of the italians Cennino Cennini‟s Trattato della Pittura (c. 1398) and Giorgio Vasari‟s Le Vite de più eccelenti architetti, pittori, et scultori italiani, da Cimabue, insino a tempi nostril (1550); of the portugueses Filipe Nunes‟s Arte da Pintura, Symetria e Perspectiva (1615); as well as the dictionary of terms of Rafael Bluteau‟s Vocabulario Portuguez e Latino (1712) and the text Segredos necessarios para os officios, artes e manufacturas, e para muitos objectos sobre a economia domestica (1794). We also observed artistic knowledge present in some of the books published by the Casa Literária do Arco do Cego and partner publishers (1799 to 1801). Several elements to the composition of this research came from contemporary studies in the areas of architecture and conservation restoration related to Jesuit constructions of art and colonial painting and scientific analyses of these materials / Com base na História da Ciência, esta pesquisa buscou conhecer os materiais usados como pigmento e as especificidades da produção artística colonial brasileira a partir da literatura referente às artes decorativas do período. Para conhecer um pouco sobre esses materiais, percorremos os tratados de pintura dos italianos Cenino Cennini, Trattato della pittura (c.1398), e Giorgio Vasari, Vida dos artistas (1550); dos portugueses Felipe Nunes, Arte da pintura, symetria e perspectiva (1615); assim como o dicionário de termos de Rafael Bluteau, Vocabulario portuguez e latino... (1712), e o texto Segredos necessarios para os officios, artes e manufacturas, e para muitos objetos sobre a economia doméstica (1794). Recorremos também aos conhecimentos artísticos presentes em alguns dos livros publicados pela Casa Literária do Arco do Cego e por editoras parceiras (1799 a 1801). Diversos elementos para a composição desta pesquisa vieram ainda dos estudos contemporâneos das áreas de arquitetura e conservação e restauração relacionados às construções jesuíticas, à arte e à pintura colonial e às análises científicas desses materiais

Title page, table of contents and abstract only. The complete thesis in print form is available from the University of Adelaide Library. / "This thesis argues that during the decade 1983-93 South Australia’s heritage legislation was not effective in protecting Adelaide’s traditional built character. The Bannon government was committed to growth through major developments during an economic recession, and many of those developments entailed at least the partial demolition of heritage-listed buildings." --p. iv. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1277500 / Thesis (Ph.D.) -- University of Adelaide, School of History and Politics, 2007

Title page, table of contents and abstract only. The complete thesis in print form is available from the University of Adelaide Library. / "This thesis argues that during the decade 1983-93 South Australia’s heritage legislation was not effective in protecting Adelaide’s traditional built character. The Bannon government was committed to growth through major developments during an economic recession, and many of those developments entailed at least the partial demolition of heritage-listed buildings." --p. iv. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1277500 / Thesis (Ph.D.) -- University of Adelaide, School of History and Politics, 2007

[pt] Hoje, muito se discute sobre a preservação de arte contemporânea; já não se trata de um assunto incomum para os profissionais do campo. Porém, conciliar o exercício da conservação-restauração com o modus operandi característico da produção artística contemporânea permanece sendo um trabalho repleto de complexidade, visto que esta última tem como uma de suas premissas básicas elaborar situações específicas que, em sua maioria, desafiam os cânones da teoria da produção de conhecimento e da prática da preservação cultural. Em outras palavras: a natureza dos trabalhos de arte contemporânea convocam a revisões epistemológicas da arte, suas áreas afins – como a conservação-restauração – e, consequentemente, do próprio mundo real enquanto coletividade construída. Na presente dissertação, a proposta é analisar, sob esta abordagem, a importância do potencial transformador da arte atual e de quais formas ele pode – ou não – ser preservado/mantido, tomando como estudo de caso a exposição Queermuseu: cartografias da diferença na arte brasileira, seus embates e desdobramentos no espaço-tempo, que engendraram uma série de contribuições para a discussão acerca do lugar da arte e da preservação cultural na sociedade. / [en] Today, much is discussed about the preservation of contemporary art; it is no longer an uncommon subject for professionals in the field. However, reconciling the exercise of conservation-restoration with the characteristic modus operandi of contemporary artistic production remains a work full of complexity, since the latter has as one of its basic premises the elaboration of specific situations that, for the most part, defy the canons of the theory of knowledge production and the practice of cultural preservation. In other words: the nature of works of contemporary art call for epistemological revisions of art, its related areas – such as conservation-restoration – and, consequently, the real world itself as a constructed collectivity. In the present dissertation, the proposal is to analyze, under this approach, the importance of the transforming potential of current art and in what ways it can – or cannot – be preserved/maintained, taking as a case study the exhibition Queermuseu: cartografias da diferença na arte brasileira, its clashes and developments in space-time, which engendered a series of contributions to the discussion about the place of art and cultural preservation in society.