A DSC study of the effect of lead pigments on the drying of cold pressed linseed oil

White, Rachel; Thomas, Paul; Phillips, M. R.; Wuhrer, Richard

doi:10.1007/s10973-005-0642-5

Cited by 16 publications

(6 citation statements)

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“…Mass Uptake. λ 0 and t 0 values show that LW catalyzes the mass uptake both in linseed oilin agreement with previous observations 28, 46 and safflower oil, as the apparent time constants are both about one order of magnitude bigger than those of the corresponding oils alone, and t 0 values are one order of magnitude smaller. As far as UB-based paints are concerned, the one with linseed oil presents a similar apparent time constant and the same order of magnitude but the bigger value of t 0 , with respect to the oil alone, indicating that UB causes a small acceleration of the oxygen uptake in linseed oil.…”

Section: Drying Timesupporting

confidence: 91%

“…37,45 Lead ions act as through driers, 21 which are able to efficiently catalyze the paint curing and accelerate oxygen uptake and autoxidation. 21,28,46 Synthetic UB is a sulfurcontaining sodium aluminum silicate. Its general formula is (NaCa) 8 [Al 6 Si 6 O 24 ](SO 4 ,S,Cl) 2 , 43 and the deep blue color of the pigment is due to the sulfur-containing radical anions inside the aluminosilicate framework.…”

Section: Introductionmentioning

confidence: 99%

“…LW has been historically the most important of all white pigments and the most common is a synthetic pigment2PbCO 3 ·Pb(OH) 2 . Lead, in lead-based pigments, reacts with acidic moieties in oil paints to form RCOO–Pb–OOCR bonds, which are believed to make the paint more durable by increasing the cross-linking density. , Lead ions act as through driers, which are able to efficiently catalyze the paint curing and accelerate oxygen uptake and autoxidation. ,, Synthetic UB is a sulfur-containing sodium aluminum silicate. Its general formula is (NaCa) 8 [Al 6 Si 6 O 24 ](SO 4 ,S,Cl) 2 , and the deep blue color of the pigment is due to the sulfur-containing radical anions inside the aluminosilicate framework .…”

Section: Introductionmentioning

confidence: 99%

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Oxidation and Cross-Linking in the Curing of Air-Drying Artists’ Oil Paints

Pizzimenti

Bernazzani

Tiné

et al. 2021

ACS Appl. Polym. Mater.

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In this study, the chemistry of air-drying artist’s oil paint curing and aging up to 24 months was studied. The objective is to improve our molecular understating of the processes that lead to the conversion of the fluid binder into a dry film and how this evolves with time, which is at the base of a better comprehension of degradation phenomena of oil paintings and relevant to the artists’ paint manufacturing industry. To this aim, a methodological approach based on thermogravimetric (TG) analysis, differential scanning calorimetry (DSC), gas chromatography–mass spectrometry (GC–MS), and analytical pyrolysis coupled with gas chromatography and mass spectrometry (Py–GC–MS) was implemented. Model paintings based on linseed oil and safflower oil (a drying and a semidrying oil, respectively) mixed with two historically relevant pigmentslead white (a through drier) and synthetic ultramarine blue (a pigment often encountered in degraded painting layers)were investigated. The oil curing under accelerated conditions (80 °C under air flow) was followed by isothermal TG analysis. The oxygen uptake profiles were fit by a semiempiric equation that allowed to study the kinetics of the oil oxidation and estimate oxidative degradation. The DSC signal due to hydroperoxide decomposition and radical recombination was used to monitor the radical activity over time and to evaluate the stability of peroxides formed in the paint layers. GC–MS was performed at 7 and 24 months of natural aging to investigate the noncovalently cross-linked fractions and Py–GC–MS to characterize the whole organic fraction of the model paintings, including the cross-linked network. We show that the oil–pigment combination may have a strong influence on the relative degree of oxidation of the films formed with respect to its degree of cross-linking, which may be correlated with the literature on the stability of painting layers. Undocumented pathways of oxidation are also highlighted.

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Section: Drying Timesupporting

confidence: 91%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Oxidation and Cross-Linking in the Curing of Air-Drying Artists’ Oil Paints

Pizzimenti

Bernazzani

Tiné

et al. 2021

ACS Appl. Polym. Mater.

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“…They are characterised by their excellent penetration into crevices, adherence to the substrate, their inhibitive and passivating action at the metal and paint interface in the presence of an electrolyte, and by dense, elastic paint layers (Brock 2000;Mayne 1946Mayne , 1970Sederholm and Forssander 2002). Lead compound pigments in combination with reactive linseed oils result in high oxidation rates and short drying times (White et al 2005). The red lead pigment, lead (II, IV) oxide, is a lead oxide spinel (called lead superoxide), with the non-stoichiometric chemical composition 2PbO•PbO2 (Estaugh et al 2008, 227-228).…”

Section: Primer Paint Pigments 10mentioning

confidence: 99%

The Concept of Historical Aluminium-Pigmented Anticorrosive Armour Paints, for Sustainable Maintenance of Ferrous Heritage

Källbom

2021

International Journal of Architectural Heritage

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This paper describes the concept of a historical, anticorrosive paint type (armour paint), used on outdoors located ferrous substrates from the early to the mid-20th century. Synthesis from the archive and research reports findings conceptualises a 2 + 2 paint layer system. The system involves red lead linseed oil primer and a top drying oil paint pigmented with micaceous iron oxide and metallic aluminium pigments. This results in excellent barrier properties, high density and elastic paint layers. If moisture reaches the metal and paint interface, the primer acts inhibitive and passivating on the corrosion reactions. The photooxidative deterioration of the paint binder is retarded by the pigment's ability to reflect light, which affects the lifetime of the paint system. Today, this paint concept is almost forgotten, but associated knowledge of the paint types, paint manufacturing and craft skills could contribute to a sustainable maintenance of ferrous heritage. The authentic concept is, despite its use of a red lead primer, relevant for objects with unique heritage values. The top paints could prolong the lifetime of objects already painted with red lead. A modified concept could initiate development of environmentally beneficial alternatives with VOC-free renewable binders, complex phosphate primers and zinc oxide addition.

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“…The study was carried out on model paint systems comprising a simple mixture of linseed oil (a model drying oil [1,2]) and lead white (2PbCO 3 •Pb(OH) 2 ), that is a through dryer [31][32][33], or ultramarine blue ((NaCa) 8 [Al 6 Si 6 O 24 ] (SO 4 ,S,Cl) 2 ), that is a slow dryer [1].…”

Section: Introductionmentioning

confidence: 99%

Oil crystallization properties as an index for monitoring early stage curing of oil-based paints: DSC analysis on linseed oil systems

Pizzimenti

Saitta

Signorelli

et al. 2022

J Therm Anal Calorim

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In this work, we propose to follow the crystallization capability of oils in oil-based paints, during curing, as an indirect index of the matrix status in the early stages of paint film formation that usually are indicative and crucial to understand the process evolution. To proof the concept, the oil crystallization properties were investigated through DSC measurements on samples of both unpigmented linseed oil and two model paints, composed by lead white + linseed oil (LWLO) and ultramarine blue + linseed oil (UBLO), at different ageing time at room and oxygen-limiting conditions. The results indicate that the curing process strongly affects the oil’s ability of forming crystals in the paint layers, and the proposed experimental approach is rather suitable and sensitive enough to discriminate differences between the action of pigments and environmental conditions. On the other hand, despite the simplicity and the potentiality, this approach is limited at the early stages of paint curing offering an index of the overall matrix status and therefore must be intended as a complementary method that has to be integrated with other approaches if the aim is to explore in detail the chemical and physical aspects of the curing process.

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A DSC study of the effect of lead pigments on the drying of cold pressed linseed oil

Cited by 16 publications

References 0 publications

Oxidation and Cross-Linking in the Curing of Air-Drying Artists’ Oil Paints

Oxidation and Cross-Linking in the Curing of Air-Drying Artists’ Oil Paints

The Concept of Historical Aluminium-Pigmented Anticorrosive Armour Paints, for Sustainable Maintenance of Ferrous Heritage

Oil crystallization properties as an index for monitoring early stage curing of oil-based paints: DSC analysis on linseed oil systems

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