Facade Paints Research Articles

UV stability of polymeric binder films used in waterborne facade paints

The UV-stability study of four polymeric binders for water-borne paints, based on acrylic, styrene-acrylic, vinyl acetate and vinyl acetate-butyl acrylate (co)polymers is described. To the best of our knowledge the UV stability of this set of binders relevant to decorative industry is systematically compared for the first time. Thin films obtained from the respective latexes were irradiated with UV light (λ≥275nm) and analysed using electrokinetic potential (ζ-potential), FTIR ATR spectroscopy, SEM microscopy and differential scanning calorimetry (DSC). The films obtained from different latexes displayed distinct changes in their surface composition and response to UV-irradiation. Among the studied compositions, the vinyl acetate-based ones seem to be the least prone to UV-degradation in the absence of other components typically present in paint formulations. The analytical techniques employed in this study are shown to be complementary and provide information on different regions of the surface layer, depending on their effective probing depth. Especially, a combination of FTIR and ζ-potential measurements is shown useful to clarify the nature of the carbonyl groups formed during photodegradation.

Conversion of nitrogen oxides on commercial photocatalytic dispersion paints

In the present study, photocatalytic reactions of nitrogen oxides (NO x = NO + NO 2) were studied on commercial TiO 2 doped facade paints in a flow tube photoreactor under simulated atmospheric conditions. Fast photocatalytic conversion of NO and NO 2 was observed only for the photocatalytic paints and not for non-catalytic reference paints. Nitrous acid (HONO) was formed in the dark on all paints studied, however, it efficiently decomposes under irradiation only on the photocatalytic samples. Thus, it is concluded that photocatalytic paint surfaces do not represent a daytime source of HONO, in contrast to other recent studies on pure TiO 2 surfaces. As main final product, the formation of adsorbed nitric acid/nitrate anion (HNO 3/NO 3 −) was observed with near to unity yield. In addition, traces of H 2O 2 were observed in the gas phase only in the presence of O 2. Formation of the greenhouse gas nitrous oxide (N 2O) could be excluded. The uptake kinetics of NO, NO 2 and HONO was very fast under atmospheric conditions (e.g. γ(NO + TiO 2) > 10 −5). Thus, the uptake on urban surfaces (painted houses, etc.) will be limited by transport. For a hypothetically painted street canyon, an average reduction of nitrogen oxide levels of ca. 5% is estimated. Since the harmful HNO 3/NO 3 − is formed on the surface of the photoactive paints, whereas it is formed in the gas phase in the atmosphere, the use of photocatalytic paints may also help to reduce acid deposition, e.g. on plants, or nitric acid related health issues.

Synthetic TiO2 nanoparticle emission from exterior facades into the aquatic environment

We present direct evidence of the release of synthetic nanoparticles from urban applications into the aquatic environment. We investigated TiO(2) particles as these particles are used in large quantities in exterior paints as whitening pigments and are to some extent also present in the nano-size range. TiO(2) particles were traced from exterior facade paints to the discharge into surface waters. We used a centrifugation based sample preparation which recovers TiO(2) particles between roughly 20 and 300nm. Analytical electron microscopy revealed that TiO(2) particles are detached from new and aged facade paints by natural weather conditions and are then transported by facade runoff and are discharged into natural, receiving waters. Microscopic investigations are confirmed by bulk chemical analysis. By combining results from microscopic investigations with bulk chemical analysis we calculated the number densities of synthetic TiO(2) particles in the runoff.

Impact of acidic precipitation to ageing of painted facades’ rendering

This paper presents the research of the impact of acidic precipitation on painted building facades’ rendering. Four typical kinds of the building facade paints have been chosen. The moisturing–drying cycling laboratory tests simulating acidic atmospheric precipitations and also natural weathering in the field have been carried out. A significant effect on the painted render during moisturing by acidic solutions with the successive drying out has been found, and this ought to be taken into account when setting up the conditions of artificial aging tests in order to predict and compare the weather resistance of painted renderings. The research has shown that the growth of the intensity of initial water absorption and deterioration rates is significantly influenced by the presence of acid depositions on a painted surface of rendering during both artificial laboratory and natural weathering tests. The results of the tests have discovered that acidic depositions are one of several very important weathering factors that should be taken into account.

BUILDING FACADE PAINTING COMPLEX PROCESS MULTICRITERIA EVALUATION/FASADŲ DAŽYMO DAUGIAKRITERINIS VERTINIMAS TINKLINIO MODELIO MAZGŲ „IŠPJOVIMO” IR SPRENDIMŲ DAUGIAPAKOPĖS SINTEZĖS METODAIS

Today there are many multicriteria evaluation methods used in building projects. They enable to make component (complex) evaluations of the task. Before a multicriteria evaluation of building facade complex process we develop a technological network model which represents technological systems and work performance variants graphically. We use technological network model junctions “cut” method for finding faster final result, for reducing alternative decisions number and facilitating calculations. This method permits to reject not irrational variants from calculations. Facade painting model consists of the following partial processes: surface preparing, priming, putting and painting. Making multicriteria decisions synthesis all these processes are interpreted as stages. It's necessary to determine the importance of each stage with respect to another stage (stage significance). To find stage significance it's possible to use expert, pair comparison methods, etc. Each stage consists of a certain number of alternatives. For comparison and evaluation of these alternatives, we produce a system of criteria (technical-economical indicators and qualitative characteristics). Using technological network junctions “cut” method, decision multistage synthesis method and carrying out multicriteria evaluation, it is possible to make a more precise alternative decisions analysis, evaluating the stage significance. This is very important for customers, contractors, projectors, etc.

BUILDING FACADE PAINTING COMPLEX PROCESS MULTICRITERIA EVALUATION

Summary Today there are many multicriteria evaluation methods used in building projects. They enable to make component (complex) evaluations of the task. Before a multicriteria evaluation of building facade complex process we develop a technological network model which represents technological systems and work performance variants graphically. We use technological network model junctions “cut” method for finding faster final result, for reducing alternative decisions number and facilitating calculations. This method permits to reject not irrational variants from calculations. Facade painting model consists of the following partial processes: surface preparing, priming, putting and painting. Making multicriteria decisions synthesis all these processes are interpreted as stages. It's necessary to determine the importance of each stage with respect to another stage (stage significance). To find stage significance it's possible to use expert, pair comparison methods, etc. Each stage consists of a certain numb...