Surface treatment of 3D-printed objects with coatings, besides protection against environmental influences, offers the improvement of visual appearance of the printed elements. In order to design an optimum surface system, the physical and chemical properties of polymers surfaces should be well-known. In the present study, 3D-printed samples of acrylonitrile-butadiene-styrene, poly(lactic acid) and poly(lactic acid) with wood flour additive were coated with three different types of coating, namely solvent borne alkyd coating, water borne acrylic coating and coating made of acrylonitrile-butadiene-styrene diluted in acetone. The surface properties of substrates and the properties of surface systems were assessed with different methods. The results revealed the surfaces of polymers having hydrophobic character, whereas the color, gloss, surface roughness and coating film thickness of coated surfaces depend on the characteristics of particular coatings. Finally, the adhesion of coatings was shown to be appropriate, but dependent on substrate surface porosity and chemical properties of both substrate surface and coating asset.

Parquet flooring is one of the most common types of flooring, the surface of which can be covered with various coatings. To avoid possible damage to the parquet during use, it is necessary to test the surfaces before installation according to various non-standard and standard protocols. The present study provides an overview of the interactions between the properties of selected waterborne coatings (solids content, hardness, resistance to cracking, tensile strength) and the properties of oak wood flooring surfaces (dry film thickness, coating adhesion, resistance to scratching, impact, abrasion and cold liquids). The tests conducted showed that the performance of the surface systems was highly dependent on the coating formulations, as they were either one- or two-component systems. Although no major differences in surface resistance to cold liquids were found, there was a correlation between coating thickness, hardness and tensile strength. The harder coatings had higher tensile strengths and lower elongations. The coatings with higher tensile strength and better hardness achieved better adhesion properties. The coatings that exhibited ductile behavior showed the worst scratch resistance. A statistically significant relationship was found between the higher resistance of the flooring systems to impact stress and the improved abrasion resistance. The obtained results provide potential end users of surface coatings with valuable information on the quality that can be expected in wood flooring.

The purpose of this study was to comparatively investigate the behavior of silicate and sol-silicate coatings non-modified or modified with an organosilane on wood and on wood pre-coated with silica-mineralized primers. Adhesion strength, morphology, and water permeability and related damages were studied to evaluate the possibility of utilizing such inorganic-based coating systems for durable protection of wood without or with relatively cheap and water-borne primers. Potassium silicate and potassium methylsiliconate aqueous solutions and a colloidal silica were used for the preparation of the coatings. The white coating paints were brushed on beech wood substrates at a rate of 220 g·m⁻². The coatings exhibited good coverage ability. The pull-off adhesion strength values appeared to be related to pH following a polynomial law. The adhesion strength for the silicate coatings were adequate (above 3 MPa and up to 5 MPa) for wood, whereas the values for the sol-silicates were too low for practical applications. The adhesion values were in general higher for the samples cured in a climate room (23 ± 3 °C and 75 ± 2% relative humidity) than the samples cured in the ambient atmosphere of the laboratory (23 ± 3 °C and 25 ± 5% relative humidity). The presence of microdefects (cracks, holes) was revealed in the coating layers by optical and scanning electron microscopy. The surface roughness parameters assessed by confocal scanning laser microscopy were dependent on the magnification applied for their measurement. The arithmetic average roughness S_a was between 5 µm and 10 µm at magnification 5× and between 2.5 μm and 10 µm at magnification 20×. The maximum peak-to-valley height S_z confirmed the presence of open pores emerging through the coatings. The open pores constitute free pathways for water ingress through the coatings, and could explain the high water absorption of the coatings including the methysiliconate-containing silicate coating and despite the relatively high water contact angle and low wettability exhibited by this sample. The post-application of a hydrophobizing solution containing hexadecyltrimethoxysilane and dimethyloctadecyl[3-(trimethoxysilyl)propyl]ammonium chloride considerably reduced the water permeability, while application of nanosilica-containing organic primers increased the adhesion for the coatings. Silicate coatings with adhesion great enough and resistance against water damages can be generated on wood even without a primer using low silica-to-alkali ratio binders and an organosilane additive. The sol-silicate coatings appear to be applicable only with a primer. The improvement of the paint formulations to control the formation of microcracks and open pores could be useful to reduce the liquid water permeability and increase durability. Otherwise, the application of a hydrophobizing treatment can be used for this purpose.

Due to their strong renewal power, the invasive tree species are spreading rapidly, especially in abandoned agricultural and forest areas and along traffic routes and water courses. One way of their restriction is the promotion of their...