Influence of weather conditions on the durability of acrylic-polyurethane car coatings in an industrial area

The influence of weather conditions on the durability of acrylic-polyurethane car coatings during their exposure to industrial plants (Grupa Azoty, Zakłady Chemiczne "Police" SA) was investigated. The surface structure and the general appearance of the paint coatings (after 16 months of the test) were examined using an optical microscope and a scanning electron microscope, an optical profilometer and a gloss meter. X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FTIR) were used to study the composition and chemical structure of the coatings. Convex spots of various sizes were observed on the surface of the tested coatings. Quantitative profilometric analysis showed a clear increase in surface roughness. However, the results of the XPS and FTIR tests did not confirm the chemical degradation of the tested samples. It was shown that the convexities observed on the surfaces of the aged coatings were atmospheric deposits consisting mainly of oxygen, calcium, phosphorus, iron, silicon and carbon. Thorough cleaning of the surfaces resulted in their complete removal.

Colour Stabilisation of Surface of Four Thermally Modified Woods with Saturated Water Vapour by Finishes

This paper deals with the influence of the type of transparent surface finish on the change of colour of the surfaces of native wood, and thermally treated wood, with saturated water vapour. In the experiment, alder, European beech, Paper birch, and Norway maple wood were thermally treated at a temperature of 135 °C under saturated water vapour for six hours. Three various types of surface finishes (acrylic-polyurethane, polyacrylic and aldehyde resin, and alkyd resin) were applied onto the wood surfaces. The colours of the surfaces in the system, CIE L*a*b* (lightness, coordinates a* and b*, chroma and hue angle), were measured during finishing and natural ageing behind glass windows in an interior, over a period of 60 days. The results show that the changes in the yellowness index, and the total colour differences after the application of individual surface finishes to wood species, changed because of sunlight exposure. Moreover, it is clear that different wood finishes behaved differently on all of the wood species. An analysis is presented in this paper.