Caffeine and TiO2 Nanoparticles Treatment of Spruce and Beech Wood for Increasing Transparent Coating Resistance against UV-Radiation and Mould Attacks

Abstract

The effect of the initial modification of beech and spruce wood using a solution of caffeine and of a commercial product FN-NANO® FN-1 containing a water dispersion of TiO2 nanoparticles for increasing the service life of a transparent oil and acrylate coatings during 6 weeks of artificial accelerated weathering was tested. Changes in colour, gloss, and the contact angle of water were monitored. Degradation of the coating film was also evaluated visually and microscopically. The resistance of the coatings to mould growth was also subsequently tested. Based on the results, it is possible to recommend the initial treatment of spruce and beech wood with a 2% caffeine solution or 15% solution of FN-NANO® dispersion to increase the overall life of a transparent acrylic coating in exterior applications. No positive effect of the applied treatments was observed with the oil coating. In addition, lower concentrations of FN-NANO® did not have a sufficient effect, and the synergistic effect of using FN-NANO® in a mixture with a 1% caffeine solution was also not confirmed.

Glossiness Evaluation of Coated Wood Surfaces as Function of Varnish Type and Exposure to Different Conditions

“…The gloss in the perpendicular direction was almost constant for 1 h radiation, and it then decreased for the next 8 h of exposure. Overall, the gloss of the coating layer decreased with the exposure time to radiation, predicting the degradation of the surface layer [17]. In a previous study, Irmouli et al [31] estimated the surface degradation by quantifying the cracks at the surface layer.…”

Caffeine Interactions with Wood Polymers

“…Caffeine (C) (1,3,7-trimethyl-3,7-dihydro-1H-purin-2,6-dion) appears to be a suitable candidate for wood protection against biological attacks [11][12][13][14][15][16][17][18][19][20][21]. This methylxanthine (Figure 1) is produced by coffee tree or the plants such as legumes and certain types of vegetables.…”

“…Pure caffeine was also applied to wood materials under various concentrations and treatment conditions [17][18][19]. Caffeine in various mixtures has already been tested [9,20,21].…”

“…Pure caffeine was also applied to wood materials under var concentrations and treatment conditions [17][18][19]. Caffeine in various mixtures has alre been tested [9,20,21]. However, there are no studies about the chemical interactions of caffeine and i vidual primary wood structures, with the exception of caffeine as drug-coated cellu wrapping [22].…”

Multi-Functional Luminescent Coating for Wood Fabric Based on Silica Sol-Gel Approach

“…Wood is a natural material mostly composed of cellulose, lignin, and hemicellulose, which is uneven distributed in the cell and intercellular layer [1][2][3][4]. Therefore, the wood contains a large number of hydroxyl groups, which are susceptible to water to cause the damage of the wood.…”