Colloidal Particles of Ca(OH)2:  Properties and Applications to Restoration of Frescoes

Ambrosi, Moira; Dei, Luigi; Giorgi, Rodorico; Neto, Chiara; Baglioni, Piero

doi:10.1021/la010269b

Cited by 193 publications

(164 citation statements)

References 21 publications

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“…Among nanomaterials, nanolime attracted an increasing interest, due to its potential as consolidating product for calcareous materials, such as frescos, limestones and lime-based renders and plasters. Nanolimes are colloidal alcoholic dispersions of calcium hydroxide nanoparticles, with spherical to hexagonal shape and a size ranging from 50 to 600 nm [4][5][6][7][8]. Thanks to the nano to submicrometric size of the particles and to the alcoholic solvent, nanolimes have a high reactivity and a high lime concentration, which provide a better consolidating effect than traditional lime-based consolidants (e.g., limewater) [9,10].…”

Section: Introductionmentioning

confidence: 99%

Optimization of nanolime solvent for the consolidation of coarse porous limestone

et al. 2016

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The potentialities of nanomaterials for application in the field of conservation have been widely investigated in the last two decades. Among nanomaterials, nanolimes, i.e., dispersions of lime nanoparticles in alcohols are promising consolidating products for calcareous materials. Nanolimes are effective in recovering the very superficial loss of cohesion of decayed materials, but they do not always provide sufficient mass consolidation. This limitation is mainly related to the deposition of the nanoparticles nearby the surface of the material. Experimental research has been set up with the aim of improving the in-depth deposition of lime nanoparticles. Previous research by the authors has shown that nanolime deposition within a substrate can be controlled by adapting the nanolimes properties (kinetic stability and evaporation rate) to the moisture transport behavior of the substrate. Nanolime properties can be modified by the use of different solvents. In this research, nanolime dispersions have been further optimized for application on Maastricht limestone, a coarse porous limestone. Firstly, nanolimes were synthesized and dispersed in ethanol and/or water, both pure and mixed in different percentages. Subsequently, based on the kinetic stability of the nanolime dispersions, the most promising solvent mixtures were selected and applied on the limestone. The deposition of lime nanoparticles within the limestone was studied by phenolphthalein test, optical microscopy and scanning electron microscopy. The results confirm that nanolime dispersed in a mixture of ethanol (95 %) and water (5 %) can guarantee a better nanoparticles in-depth deposition within coarse porous substrates, when compared to dispersions in pure ethanol.

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Section: Introductionmentioning

confidence: 99%

Optimization of nanolime solvent for the consolidation of coarse porous limestone

et al. 2016

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“…It is also clear that the addition of nanoparticles leads to an increase in the values of polymer uptake. This may be related to the deposition of nanoparticles in the pores of the limestone samples [60,61]. Completed data, as listed in Tables 2 Table 2.…”

Section: Polymer Uptakementioning

confidence: 99%

Performance of Clay, SiO2, Ca(OH)2 and CaCO3 - Polymeric Nanocomposites for Conservation and Preservation of Limestone Artworks

Aldoasri¹,

Darwish²,

Adam³

et al. 2018

Preprint

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Environmental deterioration factors are constantly increasing, causing unwanted aesthetic changes to stone artworks due to exposure to various physical and chemical deterioration factors. Inorganic nanoparticlefilled polymer composites have extended their multiple functionalities to various applications, including cultural heritage conservation. Therefore, this study has examined the effects of clay, SiO2, Ca(OH)2 and CaCO3 nanomaterials in the enhancement of the physicomechanical properties of limestone monuments, the aim of the present work being to evaluate comparatively the effectiveness of nanoparticles as consolidation and protection material for limestone artworks. The nanoparticles were added to an acrylic-based copolymer (polyethylmethacrylate (EMA)/methylacrylate (MA) (70/30), in order to improve its physiochemical and mechanical properties, and produced a significant improvement in the ability of the polymers to consolidate and protect the stone. The synthesis process of nanoparticles/polymer nanocomposite has been prepared by an in situ emulsion polymerization system. The nanocomposites contained poly (EMA/MA) with a solid content of 3% [poly (EMA/MA)] in the absence and presence of 5% nanoparticles (0.15 g nanoparticles). Samples were subjected to artificial aging by relative humidity/temperature and acid/salt crystallization weathering to show the optimum conditions of durability and the effectiveness of the nano-mixture in improving the physical and mechanical properties of the stone material. To ensure that the treatment had no negative effects on the physical characteristics of the limestone, the properties of the treated limestone samples were evaluated comparatively before and after artificial aging by the conduct of microstructural (phase morphology studied by means of scanning electron microscopy) and aesthetic (colour and lightness measured by spectrophotometry) analyses. Also used were measurement of static contact angle of water droplets on the surface of the samples, total immersion water absorption, compressive Preprints (www.preprints.org) | NOT PEER-REVIEWED | Posted: 7

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“…Os nano-materiais de hidróxido de cálcio e de hidróxido de magnésio foram preparados com base no procedimento descrito por Baglioni [5][6]. Os parâmetros experimentais estudados foram a atmosfera de síntese (ar e azoto), a temperatura (23, 60 e 90 °C) e a concentração dos reagentes iniciais (soluções sobressaturadas).…”

Section: Sínteseunclassified

Preliminary studies of consolidation of wall paintings: synthesis and characterisation of nanolime

Girginova¹,

Galacho²,

Mirão³

et al. 2016

Cons. Património

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ResumoNeste trabalho apresentam-se os resultados da síntese e da caracterização de nano-materiais de hidróxido de cálcio e de hidróxido de magnésio visando a sua aplicação como consolidantes de suportes com pintura mural. Este estudo preliminar constitui a etapa inicial de um projeto em curso e que tem como principal objetivo o desenvolvimento de novas estratégias de síntese de nano-materiais inovadores para conservação e restauro de revestimentos antigos. AbstractIn this publication, we report the synthesis and characterization of calcium and magnesium hydroxides nanoparticles for consolidation of mural paintings. Some preliminary results are discussed. This research is the initial part of our ongoing project which aims to develop new synthetic strategies towards novel and innovative materials for preservation and restoration of old renders. O presente trabalho apresenta os procedimentos e resultados obtidos na síntese de nano-materiais de hidróxido de cálcio e de hidróxido de magnésio. Foi estudada a influência de alguns dos parâmetros de síntese, nomeadamente, tipo de atmosfera, temperatura e concentração de reagentes, nas propriedades morfológicas e estruturais desses materiais, recorrendo à difração de raios X (DRX) e à microscopia eletrónica de varrimento acoplada com microanálise de raios X (MEV). Palavras-chaveAs fases seguintes deste trabalho consistirão na avaliação da eficácia dos consolidantes sintetizados, que envolverá numa primeira etapa a sua aplicação em laboratório em substratos de argamassas de cal e, posteriormente, em painéis in situ. Procedimento experimental ReagentesForam usados cloreto de cálcio (Sigma Aldrich), cloreto de magnésio (Alfa Aesar) e hidróxido de sódio (Eka) de grau p.a. e sem purificação adicional. Na preparação das soluções e lavagem das amostras foi utilizada água Milli-Q do tipo I. SínteseOs nano-materiais de hidróxido de cálcio e de hidróxido de magnésio foram preparados com base no procedimento descrito por Baglioni [5][6]. Os parâmetros experimentais estudados foram a atmosfera de síntese (ar e azoto), a temperatura (23, 60 e 90 °C) e a concentração dos reagentes iniciais (soluções sobressaturadas). Na Tabela 1 apresenta-se a designação das amostras preparadas, assim como o resumo das principais condições de síntese usadas. Caracterização microestrutural e morfológicaAs amostras foram caracterizadas recorrendo às técnicas de difração de raios X (Bruker, Discover) e de microscopia eletrónica de varrimento (Hitachi 3700N) Tabela 1Resumo das principais condições de síntese usadas. Estudos preliminares para consolidação de suportes com pintura mural: síntese e caracterização de nanocais 105 acoplada a espectroscopia de raios X dispersiva de energia (Bruker Xflash 5010SDD). Resultados e discussãoOs difratogramas das amostras de Ca(OH) 2 são característicos deste tipo de materiais, permitindo inferir a presença das fases cristalinas de hidróxido de cálcio, como componente maioritário, e de carbonato de cálcio como componente minoritário. A determinação dos valores da razão ...

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Colloidal Particles of Ca(OH)₂: Properties and Applications to Restoration of Frescoes

Cited by 193 publications

References 21 publications

Optimization of nanolime solvent for the consolidation of coarse porous limestone

Optimization of nanolime solvent for the consolidation of coarse porous limestone

Performance of Clay, SiO<sub>2</sub>, Ca(OH)<sub>2 </sub>and CaCO<sub>3</sub> - Polymeric Nanocomposites for Conservation and Preservation of Limestone Artworks

Preliminary studies of consolidation of wall paintings: synthesis and characterisation of nanolime

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