Determination of nano varnish effect on wooden historic buildings conservation

The aim of this study is to produce nano varnish which can be used in the restoration and conservation process of old and worn surfaces in historical and cultural wooden buildings and to determine the protection effects. In this study, water based acrylic nano varnishes reinforced with TiO2 and Al2O3 nanoparticles are used. The conservation process with the varnishes was planned to improve resistance to outdoor and indoor effects such as pollution, dust retention, wind, rain, frost, climatic conditions, bacteria, fungus and UV of historical and cultural wooden buildings. Water born solutions and transparent nano TiO2 and Al2O3 particles were mixed mechanically and ultrasonically with water-based acrylic varnish in different ratios of 1, 2 and 4% and then nano varnishes were prepared and grouped. These varnishes prepared in groups, it was applied to the green black pine wood with brush application methods. Black pine wood coated with different varnish solutions were put to accelerated weathering cabinet (QUV) and the best varnishes were selected as the varnishes exhibited the lowest color changes by measuring color changes of the samples after and before QUV test and the varnishes were applied to the wood surfaces of the exterior wood veneer from the historical and cultural wooden structure of Armutçular Mansion in Bolu-Mudurnu. The properties of the control and nano varnishes to be used in our study and their protection effects were determined. Micro hardness, color, gloss, scratch, abrasion, aging, water vapor resistance, UV analysis, TGA, SEM, FTIR, surface contact angle, surface layer thickness and surface adhesion resistance tests of the samples prepared were performed. The results were statistically evaluated. Differences within and between groups were determined with the evaluations. Color results showed nano-TiO2 addition was more suitable than nano-Al2O3 addition according to color change analysis results. When the varnishes containing different mixtures of these two particles were examined, it was found that whitening was occurred as comparison to the control varnish and the lowest change was determined for the varnish containing 4% TiO2, 1% Al2O3 and 4% TiO2-1% Al2O3. When SEM images were examined, it was found that there was some crushing on the brush surfaces due to the misuse of the brush during varnishing or difficulty in sample preparation. No significant difference was found between the micro hardness values of the samples after variance analysis. Varnishes obtained with the addition of TiO2 were found to show the highest degree (3.derece) of scratching and abrasion. The best results were obtained from nano-Ti filled varnishes. The worst abrasion and scratching were found to the varnish with Al2O3. Nano Ti filled varnishes were found to have better surface strength than the Al filled samples. The best surface strength was found as 3.7 N/mm2 for the varnish with TiO2. The thermal properties of the samples were examined by TGA and DTG tests and no significant difference was found between the control samples. As a result of EDAX screening, Al2O3 and TiO2 particles were detected on the surface. In addition, their distribution in the varnish was determined. Particularly in the varnishes with the addition of 4% T, more agglomeration was observed than the other varnishes. In the UV analysis, nano varnish and control sample showed strong absorbance in the 200 nm - 400 nm band in the UV region. With the addition of nanoparticles, it was observed that the absorbance amount decreased at the 2nd and 3rd peaks. FTIR showed any different peaks or signs of reaction.