Investigating the effect of artists’ paint formulation on degradation rates of TiO2-based oil paints

This study reports on the effect of artists’ paint formulation on degradation rates of TiO2-based oil paints. Titanium white oil paint exists in a multitude of different recipes, and the effect of the formulation on photocatalytic binder degradation kinetics is unknown. These formulations contain, among others, one or both titanium dioxide polymorphs, zinc oxide, the extenders barium sulfate or calcium carbonate and various additives. Most research performed on the photocatalytic degradation process focusses on pure titanium white-binder mixtures and thus does not take into account the complete paint system. Since photocatalytic oil degradation is a process initiated by the absorption of UV light, any ingredient or combination of ingredients influencing the light scattering and absorption properties of the paint films may affect the degradation rate. In this study three sets of experiments are conducted, designed using the design of experiments (DoE) approach, to screen for the most important formulation factors influencing the degradation rate. The benefits of using DoE, compared to a more traditional ‘one factor at a time approach’ are robustness, sample efficiency, the ability of evaluate mixtures of multiple components as well as the ability to evaluate factor interactions. The three sets of experiments investigate (1) the influence of the TiO2 type, (2) the impact of different mixtures of two types of TiO2, ZnO and the additive aluminum stearate and (3) the influence of common extenders in combination with photocatalytic TiO2, on the photocatalytic degradation of the oil binder. The impact of the formulation on the degradation rate became apparent, indicating the shortcoming of oversimplified studies. The protective effect of photostable TiO2 pigments, even in a mixture with photocatalytic TiO2 pigments, as well as the negative effect of extenders was demonstrated. Furthermore, the ambiguous role of ZnO (photocatalytic or not) and aluminum stearate is highlighted. Neither can be ignored in a study of degradation behavior of modern oil paints and require further investigation

Effects of various factors on the adhesive strength of paint films

Translated from German (Baender, Bleche, Rohre 1977 v. 18(12) p. 537-540)Available from British Library Document Supply Centre- DSC:9022.09(CE-Trans--8073)T / BLDSC - British Library Document Supply CentreSIGLEGBUnited Kingdo

Failure Envelopes of Paint Films as Related to Pigmentation and Snelling

A suitable presentation of the tensile properties of paint films is obtained by means of T. Smith's failure envelope. The viscoelastic states of material appear distinctly on the failure envelope. Technological properties, such as strength, toughness and deformability, can also be evaluated in this way. Films of linseed alkyd, pigmented with Pb[3]O[ 4], MgO and ZnO, exhibited a shift to the energy-elastic state with increasing pigmentation. In the swollen state, this tendency is markedly reduced by swelling of the binder. The "active" effect of the pigments is diminished at higher pigment volume concentration, since reactive groups in the binder may then be lacking. For systems with inactive pigments, such as urea resin/Fe[2]O[3] and PVC- copolymer/TiO[2], failure envelopes in the dry and swollen state were found which indicate no essential change in the viscoelastic character of the films. Measurements of the systems studied could be explained qualitatively on the basis of theoretical ideas derived by T. Smith, Bueche and Halpin.SOMMAIRE FRANCAIS A SUIVREPeer reviewed: NoNRC publication: Ye

Adhesion effects with coating materials due to roughness

7.50; translated from Metalloberflaeche (1978) v. 32(6) p. 257-261SIGLELD:9022.06(BISI--19157) / BLDSC - British Library Document Supply CentreGBUnited Kingdo