Modeling the Evolution of Crosslinked and Extractable Material in an Oil‐Based Paint Model System

Oakley, Lindsay H.; Casadio, Francesca; Shull, Professor Kenneth R.; Broadbelt, Linda J.

doi:10.1002/ange.201801332

Cited by 8 publications

(10 citation statements)

References 24 publications

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“…One experiment showed that, after catalysing the formation of oligomeric structures during curing of ethyl linoleate, in the long term a Co based drier promoted a series of decomposition reactions which overwhelmed the polymerisation reactions 37 . Similar phenomena may take place in paints containing Co-based pigments where, after an initial stage in which drying and subsequently polymerisation has taken place, other reaction pathways become dominant, leading to the oxidative degradation/fragmentation of the paint film 35,37 .…”

Section: Pigments and Additivesmentioning

confidence: 59%

“…Termination reactions resulting from the recombination of radicals allow the formation of nonradical products, such as relatively unstable peroxides, or the relatively stable products of crosslinking reactions and oxidation 35 . When peroxides are formed, these will react further with time, undergoing scission and forming alcoxyl radicals (RO•).…”

Section: Oil Fractionmentioning

confidence: 99%

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Conservation Issues of Modern Oil Paintings: A Molecular Model on Paint Curing

Bonaduce,

Duce,

Lluveras-Tenorio

et al. 2019

Acc. Chem. Res.

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20th-and 21st-century oil paintings are presenting a range of challenging conservation problems that can be distinctly different from those noted in paintings from previous centuries. These include the formation of vulnerable surface 'skins' of medium and exudates on paint surfaces, efflorescence, unpredictable water and solvent sensitivity and incidence of paint dripping which can occur within a few years after the paintings were completed.Physicochemical studies of modern oil paints and paintings in recent years have identified a range of possible causal factors for the noted sensitivity of painting surfaces to water and protic solvents, including the formation of water-soluble inorganic salts and/or the accumulation of diacids at the paint surface, which are oxidation products of the oil binder. Other studies have investigated the relationship between water sensitivity and the degree of hydrolysis of the binder, the proportions of free fatty and dicarboxylic acids formed, as well as the relative content of free metal soaps. Thus far, data indicate that the qualitative and quantitative composition of the non-polymerised fractions of the oil binder cannot be solely or directly related to the solvent sensitivity of the paint film.Conclusions therefore indicate that the polymeric network, formed upon the curing of the oil plays a fundamental role; suggesting that water sensitivity -at least in some cases -may be related to the poor development, and/or polar nature of the formed polymeric network rather than the composition of the non-polymerised fractions.Poorly developed polymeric networks, in combination with the migration of polar fractions i.e. dicarboxylic and hydroxylated fatty acids towards the paint surface, can be related to other degradation phenomena, including the separation and migration of the paint binder which can lead to the presence of observable skins of medium, as well as the more alarming phenomenon of liquefying or dripping oil paints. It is thus crucial to understand the molecular composition of these Among the issues encountered, water sensitivity is proving particularly challenging, as the removal of accumulated, deposited soiling, often known as surface cleaning, traditionally relies upon water as the key component. In these cases, water may not be safely applied without causing undesirable surface disruption and pigment pick-up [3][4][5][6][7] .Water sensitivity has now been identified in model oil paint samples prepared from raw materials 4,8,9 , in samples taken from batches of manufactured paint 10 , and in several paintings [9][10][11][12][13] .Sensitivity may be limited to certain colours, may affect the whole surface of a painting, may be specific to some paint brands or lines, and may affect specific pigments across several brands 8,10,13 .Recent research has identified some of the causes and/or contributing factors relating to the changes observed in modern oils (i.e. water sensitivity and poor drying behaviour) including: the conversion of magnesium carbonate filler material use...

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Section: Pigments and Additivesmentioning

confidence: 59%

Section: Oil Fractionmentioning

confidence: 99%

Conservation Issues of Modern Oil Paintings: A Molecular Model on Paint Curing

Bonaduce,

Duce,

Lluveras-Tenorio

et al. 2019

Acc. Chem. Res.

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“…At current stage of art, its detailed kinetics can be approached only by mechanistic models available by automating the process of network generation. 166,167 Recent microkinetic model for the autoxidation of ethyl linoleate catalyzed by cobalt(II) 2-ethylhexanoate, well reproduces the key reaction outcome and enables to explore effect of temperature and catalyst concentration. 167…”

Section: Crosslinking Reactions and Side Productsmentioning

confidence: 96%

Curing of Air-Drying Paints: A Critical Review

Honzı́ček

2019

Ind. Eng. Chem. Res.

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This review article provides a comprehensive overview of curing processes relevant to air-drying paints. It is focused not only on binders derived from plant oils but also on oriental lacquers and their synthetic congeners as their solidification and hardening processes are driven by chemical reactions with air-oxygen. The main aim of this article is to bring a critical look on this subject omitting deep-seated misinterpretation and oversimplification often appearing in the field of paint technology. Such objective was achieved by utilization of the latest knowledge appearing in various areas of chemical research, e.g. organic chemistry, biochemistry, physical chemistry, computational chemistry and inorganic chemistry.

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“…The curing of a drying oil—a glycerolipid based on polyunsaturated fatty acids—involves autoxidative radical chain reactions, which are light initiated, and metal catalysed 1 – 6 . Upon curing, fatty acids in triglycerides undergo several transformations, which entail the formation of epoxy, hydroxyl, oxo and carbonyl moieties, as well as new C–C and C–O–C bonds 1 , 4 , 6 , 7 . Small oxidised molecules are formed by oxidative degradation of the fatty acid chains upon evolution of peroxyl and alkoxyl moieties 4 , 6 , and are quickly lost by evaporation 8 .…”

Section: Introductionmentioning

confidence: 99%

The stability of paintings and the molecular structure of the oil paint polymeric network

Nardelli

Martini

Lee

et al. 2021

Sci Rep

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A molecular-level understanding of the structure of the polymeric network formed upon the curing of air-drying artists’ oil paints still represents a challenge. In this study we used a set of analytical methodologies classically employed for the characterisation of a paint film—based on infrared spectroscopy and mass spectrometry—in combination with solid state NMR (SSNMR), to characterise model paint layers which present different behaviours towards surface cleaning with water, a commonly applied procedure in art conservation. The study demonstrates, with the fundamental contribution of SSNMR, a relationship between the painting stability and the chemical structure of the polymeric network. In particular, it is demonstrated for the first time that a low degree of cross-linking in combination with a high degree of oxidation of the polymeric network render the oil paint layer sensitive to water.

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Modeling the Evolution of Crosslinked and Extractable Material in an Oil‐Based Paint Model System

Cited by 8 publications

References 24 publications

Conservation Issues of Modern Oil Paintings: A Molecular Model on Paint Curing

Conservation Issues of Modern Oil Paintings: A Molecular Model on Paint Curing

Curing of Air-Drying Paints: A Critical Review

The stability of paintings and the molecular structure of the oil paint polymeric network

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