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Following an earlier study of different coloured pigments used in Roman wall-plaster paintings, this research project investigates the use of the synthetic pigment commonly known as Egyptian Blue in Romano-British wall-plaster paintings. Samples of Egyptian Blue pellets were obtained from excavations at the Romano-British sites of Fishbourne Roman Palace, near Chichester, Piddington near Northampton, Turners Hall Farm, near St Albans, and from excavations at Verulamium (Roman St Albans). The aim of this study is to determine the chemical composition, fabric and texture of each pellet as well as attempting a textural and geochemical classification of the pellets, using well established analytical techniques, particularly LA-ICP-MS and SEM-EDAX. The colour of the pellets was examined and identified using the Munsell Book of Color (Matte Finish Collection) 1973. The results of the analysis of the Egyptian Blue pellets found on Romano-British sites showed that differing amounts of silica, copper, calcium, as well as smaller amounts of other elements, were used in their manufacture. Most of the pellets examined appear to have been manufactured locally, though some were almost certainly imported. Experimental work was undertaken, both in the laboratory and out in-the-field where a reconstructed Bronze Age Clamp Kiln and an Iron Age Belgic Kiln were used, to reproduce the synthetic pigment Egyptian Blue, using a recipe similar to that used by earlier investigators. Such recently manufactured Egyptian Blue pellets were applied, as a pigment, to damp lime mortar, in an attempt to correlate the achieved colour with the firing time. Similar techniques were used in an attempt to ascertain the nature of the pigments used on the small fragments of painted wall-plaster found in a back filled trench, from Wheeler's 1930 - 33 excavations at Verulamium. On two of the fragments gas chromatographic analysis was applied to determine the nature of the binding material that might have been used. This study is thought to be the first in-depth investigation of Romano-British Egyptian Blue pellets and thereby contributes to the art history and archaeological knowledge of this period.

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Made available in DSpace on 2014-10-09T12:51:13Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:10:37Z (GMT). No. of bitstreams: 1 11257.pdf: 9782449 bytes, checksum: 9692d0a5b3355b0291e58320e6dc078d (MD5) / Tese (Doutoramento) / IPEN/T / Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP

Cette thèse porte sur l’application des images multispectrales pour l’analyse des matériaux utilisés dans une peinture par comparaison avec la photographie traditionnelle de fluorescence induite par rayons UV et la réflectoraphgie infrarouge. L’application des images multispectrales à l'étude des matériaux picturaux a été appuyée par d'autres techniques analytiques telles que la spectroscopie de réflectance et de fluorescence, la spectroscopie de fluorescence X, la spectroscopie d'absorption UV-visible et la spectroscopie infrarouge transformée de Fourier en réflectance totale atténuée. L’imagerie multispectrale a été testée comme outil de laboratoire d’identification des matériaux picturaux. Ainsi, des couches de peinture constituées de pigments (anciens et modernes), de liants (œufs et l’huile de lin) et de vernis naturels ont été analysées. Pour les matériaux organiques, des expériences de vieillissement accéléré (photodégradation et dégradation thermique) ont permis de modéliser les changements optiques et chimiques intervenant au cours de la vie d’un tableau. De plus, une analyse diagnostique a été réalisée sur deux tableaux conservés à « Accademia di San Luca » (Rome) par photographie de fluorescence induite par rayonnement UV, radiographie, spectroscopie de réflectance, spectroscopie de fluorescence X, images de fluorescence UV et réflectance multispectrale, réflectographie infrarouge multispectrale. Par rapport aux techniques traditionnelles, les images multispectrales permettent d’analyser de nombreuses régions spectrales qui, dans certains cas, permettent d’identifier le pigment et/ou des zones non homogènes de la couche superficielle picturale. Certaines gammes de longueurs d’onde infrarouge permettent notamment de voir les détails des différentes couches préparatoires, amenant à une analyse plus précise de la technique d’exécution. Cependant, une des limites des images multispectrales concerne l’identification des mélanges complexes et/ou des différentes strates de matériaux en fonction du type de filtre utilisé. / This thesis focus on the application of multispectral images for the analysis of pictorial materials in comparison with the traditional UV-fluorescence photography and infrared reflectography. The assessment of multispectral imaging for the study of pictorial materials was supported by other analytical techniques such as reflectance and fluorescence spectroscopy, X-Ray Fluorescence (XRF), UV-visible absorption spectroscopy and Total Attenuated Reflectance - Fourier Transform Infrared Spectroscopy (ATR-FTIR). The multispectral imaging was tested on swatches of pictorial layers (constituted by ancient and modern pigment), binders (egg and linseed oil) and natural varnishes. For the organic materials, accelerated ageing methods (photo-chemical and thermal degradation) were used to model the optical and chemical changes occurring during the lifetime of a painting. In addition, a diagnostic investigation was performed on two paintings placed in "Accademia di San Luca" (Rome) by means of UV-fluorescence photography, radiography, reflectance spectroscopy, X-ray fluorescence spectroscopy, UV-VIS-NIR multispectral imaging. Multispectral images, comparing to traditional techniques, permit to individuate specific spectral behaviors, and, in some cases, identify the pigment and/or non-homogeneous areas of the pictorial or varnish layers. The possibility to select some infrared wavelengths allows to see details of the preparatory layers, leading to a more accurate analysis of the technique of execution. However, the limitations of multispectral images for the identification of complex mixtures and/or different layers of materials depending on the type of filter used.

Este estudo foi realizado utilizando quatro experimentos que objetivaram: (1) Avaliar a quantidade de flúor (F-) liberada por vernizes; (2) Avaliar a quantidade de F- fraca e fortemente aderido ao esmalte dentário após uso dos vernizes; avaliar a capacidade do verniz de prevenir a (3) desmineralização do esmalte por cárie e (4) a progressão da desmineralização por erosão. Vernizes fluoretados (5,63%), contendo ou não glicerofosfato de cálcio (CaGP) a 1%, 5% e 10% foram elaborados e comparados a vernizes controle sem F-, e outros contendo apenas F- (a [2,26%] ou a [5,63%]). Placas de acrílico foram utilizadas para a avaliação da quantidade de F- liberada pelos vernizes. Um total de 72 dentes humanos foram utilizados para obter 2 amostras (a e b) de cada dente e verificar a quantidade de F- fraca e fortemente aderida ao esmalte (a) após receber o verniz fluoretado e (b) sem receber verniz. Ainda, 60 dentes bovinos foram aplanados e alisados para verificar o efeito preventivo dos vernizes em desafio cariogênico in vitro. E 108 dentes humanos foram aplanados e alisados para verificar o efeito dos vernizes na progressão da erosão in vitro. O verniz contendo F- (5,63%) e 1% CaGP foi o que liberou mais flúor ao meio (p<0,05), e esse mesmo verniz e o verniz contendo F- 5,63% promoveram uma maior quantidade de flúor fraca e fortemente aderida ao esmalte dentário (p<0,01). Entretanto esses aspectos não foram determinantes quando se verificou o efeito preventivo, pois o verniz contendo F- (2,26%) foi o que apresentou melhor efeito preventivo ao diminuir significantemente a desmineralização por cárie (p<0,05) e erosão (p<0,01) in vitro, sendo que os vernizes contendo CaGP não apresentaram esse mesmo efeito. O uso dos vernizes não foi capaz de remineralizar o esmalte que sofreu amolecimento (softening) após um desafio erosivo. Frente ao exposto, pode-se concluir que apesar do verniz de glicerofosfato de cálcio associado ao flúor promover maior liberação de flúor ao meio e maior quantidade de flúor fraca e fortemente aderida ao esmalte dentário, o mesmo não apresentou efeito preventivo favorável frente aos desafios ácidos. Portanto, o uso do glicerofosfato de cálcio de maneira combinada ao flúor na forma de verniz não apresentou efeito preventivo significativo em esmalte submetido a desafios cariogênicos e erosivos in vitro. / This study was carried out in four experiments, which aimed at: (1) assess the amount of fluoride (F-) released by the varnishes; (2) assess the amount of loosely and firmly bound F- to dental enamel after the use of varnishes; assess the ability of the varnishes to prevent (3) enamel demineralization from caries and (4) the progression of demineralization from erosion. Fluoride (5,63%) varnishes containing or not calcium glycerophosphate (CaGP) (1%, 5% or 10%) were made and compared to control varnish with no F-, and varnishes containing only F- (either 2.26% or 5.63%). Acrylic plates were used to assess the amount of F- released from the varnishes. A total of 72 human teeth were used to obtain 2 enamel samples per tooth (a and b) to assess the amount of loosely and firmly bound F- to enamel, before (b) and after (a) varnish application. Still, 60 bovine teeth were flattened and treated to assess the preventive effect of the varnishes after in vitro cariogenic challenge. Also, 108 human teeth were treated to assess the effect of the varnishes on the progression of dental erosion in vitro. The varnish containing F (5.63%) and 1% CaGP released more fluoride to the medium (p<0.05), and this same varnish together with the varnish containing F-5.63% promoted a greater quantity of loosely and firmly bound fluoride to dental enamel (p<0.01). However, these aspects were not determinants in the prevention, due to the fact that the varnish containing F (2.26%) showed better preventive effect when it decreased in vitro enamel demineralization from caries (p<0.05) and erosion (p<0.01), but the varnishes containing CaGP did not show the same effect. The use of the varnishes was not able to remineralize enamel which had already suffered softening from an erosive challenge. In view of these results, it may be concluded that, although the varnish containing CaGP with fluoride promoted greater amounts of fluoride released to the medium and greater amounts of loosely and firmly bound fluoride to dental enamel, the CaGP-F varnish did not show a preventive effect after acidic challenges. Therefore, the use of calcium glycerophosphate together with fluoride in varnishes did not show a significant preventive effect for enamel submitted to cariogenic and erosive challenges in vitro.

Este estudo foi realizado utilizando quatro experimentos que objetivaram: (1) Avaliar a quantidade de flúor (F-) liberada por vernizes; (2) Avaliar a quantidade de F- fraca e fortemente aderido ao esmalte dentário após uso dos vernizes; avaliar a capacidade do verniz de prevenir a (3) desmineralização do esmalte por cárie e (4) a progressão da desmineralização por erosão. Vernizes fluoretados (5,63%), contendo ou não glicerofosfato de cálcio (CaGP) a 1%, 5% e 10% foram elaborados e comparados a vernizes controle sem F-, e outros contendo apenas F- (a [2,26%] ou a [5,63%]). Placas de acrílico foram utilizadas para a avaliação da quantidade de F- liberada pelos vernizes. Um total de 72 dentes humanos foram utilizados para obter 2 amostras (a e b) de cada dente e verificar a quantidade de F- fraca e fortemente aderida ao esmalte (a) após receber o verniz fluoretado e (b) sem receber verniz. Ainda, 60 dentes bovinos foram aplanados e alisados para verificar o efeito preventivo dos vernizes em desafio cariogênico in vitro. E 108 dentes humanos foram aplanados e alisados para verificar o efeito dos vernizes na progressão da erosão in vitro. O verniz contendo F- (5,63%) e 1% CaGP foi o que liberou mais flúor ao meio (p<0,05), e esse mesmo verniz e o verniz contendo F- 5,63% promoveram uma maior quantidade de flúor fraca e fortemente aderida ao esmalte dentário (p<0,01). Entretanto esses aspectos não foram determinantes quando se verificou o efeito preventivo, pois o verniz contendo F- (2,26%) foi o que apresentou melhor efeito preventivo ao diminuir significantemente a desmineralização por cárie (p<0,05) e erosão (p<0,01) in vitro, sendo que os vernizes contendo CaGP não apresentaram esse mesmo efeito. O uso dos vernizes não foi capaz de remineralizar o esmalte que sofreu amolecimento (softening) após um desafio erosivo. Frente ao exposto, pode-se concluir que apesar do verniz de glicerofosfato de cálcio associado ao flúor promover maior liberação de flúor ao meio e maior quantidade de flúor fraca e fortemente aderida ao esmalte dentário, o mesmo não apresentou efeito preventivo favorável frente aos desafios ácidos. Portanto, o uso do glicerofosfato de cálcio de maneira combinada ao flúor na forma de verniz não apresentou efeito preventivo significativo em esmalte submetido a desafios cariogênicos e erosivos in vitro. / This study was carried out in four experiments, which aimed at: (1) assess the amount of fluoride (F-) released by the varnishes; (2) assess the amount of loosely and firmly bound F- to dental enamel after the use of varnishes; assess the ability of the varnishes to prevent (3) enamel demineralization from caries and (4) the progression of demineralization from erosion. Fluoride (5,63%) varnishes containing or not calcium glycerophosphate (CaGP) (1%, 5% or 10%) were made and compared to control varnish with no F-, and varnishes containing only F- (either 2.26% or 5.63%). Acrylic plates were used to assess the amount of F- released from the varnishes. A total of 72 human teeth were used to obtain 2 enamel samples per tooth (a and b) to assess the amount of loosely and firmly bound F- to enamel, before (b) and after (a) varnish application. Still, 60 bovine teeth were flattened and treated to assess the preventive effect of the varnishes after in vitro cariogenic challenge. Also, 108 human teeth were treated to assess the effect of the varnishes on the progression of dental erosion in vitro. The varnish containing F (5.63%) and 1% CaGP released more fluoride to the medium (p<0.05), and this same varnish together with the varnish containing F-5.63% promoted a greater quantity of loosely and firmly bound fluoride to dental enamel (p<0.01). However, these aspects were not determinants in the prevention, due to the fact that the varnish containing F (2.26%) showed better preventive effect when it decreased in vitro enamel demineralization from caries (p<0.05) and erosion (p<0.01), but the varnishes containing CaGP did not show the same effect. The use of the varnishes was not able to remineralize enamel which had already suffered softening from an erosive challenge. In view of these results, it may be concluded that, although the varnish containing CaGP with fluoride promoted greater amounts of fluoride released to the medium and greater amounts of loosely and firmly bound fluoride to dental enamel, the CaGP-F varnish did not show a preventive effect after acidic challenges. Therefore, the use of calcium glycerophosphate together with fluoride in varnishes did not show a significant preventive effect for enamel submitted to cariogenic and erosive challenges in vitro.

There has been a considerable effort in the last years to decrease the amount of volatile organic compounds (VOCs) present in organic coatings. The risks to human health and environmental hazards associated with VOCs, governmental directives, and economic factors are the main driving forces behind this effort. One way of achieving less or no VOC containing coating systems is to produce low viscosity resins. Hyperbranched resins owing to their globular structure have low viscosities and are promising materials for decreasing the VOCs. In this research hyperbranched resins having properties close to alkyds were synthesized. Dipentaerythritol, which was used as the core was esterified with dimethylol propionic acid. The hyperbranched polyester was then esterified with the castor oil fatty acids (Castor FA). The hydroxyl group of the ricinoleic acid present in the castor FA was modified with different amounts of linseed oil fatty acids (Linseed FA) and benzoic acid. The chemical characterization of the resins was achieved by FTIR spectroscopy and the thermal properties were determined by DSC. Then, the physical and the mechanical tests were carried out. The resins containing the Castor FA only and 32.5 % Linseed FA in addition to the Castor FA had 24 and 68 Persoz hardness, respectively. The viscosity of the resins decreased from 17.3 Pa&amp / #61655 / s to 5.8 Pa&amp / #61655 / s as the amount of the Linseed FA was increased. The resins showed excellent adhesion, gloss, flexibility and formability.

In this research hyperbranched resins containing fatty acid residues like alkyds were synthesized. Dipentaerythritol which has six hydroxyl groups was used as the core molecule, and it was transesterified with (i) castor oil, and (ii) a mixture of castor oil and linseed oil at 240&deg / C in the presence of sodium hydroxide as catalyst. The resulting molecule, in either case, was then esterified with dimethylol propionic acid at 140&deg / C in the presence of p-toluene sulfonic acid as catalyst. Melamine-formaldehyde resin was synthesized to be used with the synthesized hyperbranched resins, and it was successfully modified by all hyperbranched resins at a ratio of 3:1. FTIR spectroscopy was used to characterize the hyperbranched resins and the thermal properties were determined by DSC. DSC showed that the hyperbranched resins decomposed between 315-345&deg / C. The viscosity of the resin that was synthesized by using only castor oil was 3.0 Pa.s and by using 50% linseed oil it was 1.0 Pa.s. When reacted with dimethylol propionic acid, the former&rsquo / s viscosity increased to 7.0 Pa.s, and the second&rsquo / s viscosity increased to 3.7 Pa.s. The hyperbranched resins showed excellent adhesion, gloss, flexibility, and formability. The mixture of hyperbranched resin plus melamine-formaldehyde resin samples had higher hardness values but lower gloss, adhesion and bending resistance values than the hyperbranched resins, and they had good impact and abrasion resistances.