Acrylic Varnish Research Articles

Impact of impregnation with boron compounds on the surface hardness of varnished wood

AbstractThis study was performed to determine the impact of impregnation with boron compounds on the surface hardness of varnished wood materials. For this purpose, test specimens prepared from Oriental beech (Fagus orientalis Lipsky) and oak (Quercus petreae Lipsky), which met the requirements of ASTM D 358, were impregnated according to ASTM D 1413 with boric acid and borax by a vacuum technique. After impregnation, the surfaces were coated by cellulosic, synthetic, polyurethane, waterborne, acrylic, and acid hardening varnishes in accordance with ASTM D 3023. The surface hardness of the specimens after the varnishing process was determined in accordance with ASTM D 4366. According to the wood type, impregnation material, and varnish type, the surface hardness was highest for the oak impregnated with borax and acrylic varnish and lowest for the oak impregnated with borax and synthetic varnish. Therefore, impregnation with boron compounds showed an increasing impact on the surface hardness of the varnished wood. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007

Impacts of varnishes and impregnation chemicals on combustion properties of oak (Quercus petreae lipsky)

This study was performed to determine the effects of varnishing after impregnation with boron compounds on combustion properties of oak. For this aim, the test samples prepared from oak (Quercus petreae Liebl.) wood were impregnated according to ASTM D 1413-99 with boric acid (Ba) and borax (Bx) by vacuum technique. After impregnation, surfaces were coated by cellulosic (Cv), synthetic (Sn), polyurethane (Pu), waterborne (Wb), acrylic (Ac), and acid hardening (Ah) varnishes in accordance to ASTM D 3023. Combustion properties of samples after varnishing process were determined, according to ASTM E 160-50. According to material and process types, combustion temperature was the highest in Bx and Cv, the lowest in Ba and Ac. An important difference was not observed between without flame source combustion (WFSC) and flame source combustion (FSC). According to combustion type, impregnation material and varnish type, combustion temperature was the highest value in WFSC + Bx + acid hardening varnish combination and the lowest in WFSC + Ba + acrylic varnish combination. As a result, the tested varnishes showed an increasing impact but boron compounds showed a decreasing impact on combustion properties of oak. In consequence, for usage areas having a high risk of fire, impregnation of wood material with boron compounds before varnishing will decrease combustion temperature and provide security. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2008

Waterborne acrylic varnishes durability on wood surfaces for exterior exposure

The protection performance of varnishes applied to two different wooden substrates (maritime pine and iroko) for outdoor exposure was investigated for eight different varnish systems (with and without colorants and two different light stabilizers). All were subjected to accelerated artificial weathering and natural weathering. Several test methods were used to evaluate the appearance and physical–chemical properties of the coatings during the degradation. The results obtained lead to the selection of the best varnish formulation for the protection of wood for exterior use and provide useful evaluation of the test methods employed.

Measuring the thickness of protective coatings on historic metal objects using nanosecond and femtosecond laser induced breakdown spectroscopy depth profiling

Depth profile analysis by means of laser induced breakdown spectroscopy (LIBS) was investigated with respect to its potential to measure the thickness of different types of thin organic films used as protective coatings on historical and archaeological metal objects. For the materials examined, acrylic varnish and microcrystalline wax, the output from a nanosecond ArF excimer laser at 193 nm was found appropriate for performing a reliable profiling of the coating films leading to accurate determination of the coating thickness on the basis of the number of laser pulses required to penetrate the coating and on the ablation etch rate of the corresponding coating material under the same irradiation conditions. Nanosecond pulses at 248 nm proved inadequate to profile the coatings because of their weak absorption at the laser wavelength. In contrast, femtosecond irradiation at 248 nm yielded well-resolved profiles as a result of efficient ablation achieved through the increased non-linear absorption induced by the high power density of the ultrashort pulses.

Hybrid Sol–gel Clear Coatings for Decoration Brass Profiles

Frequently, it is desired that the original reddish to gold tones of copper, brass, and bronze surfaces are preserved when they are used in decorative areas, which are mainly interiors, but are also in architectural elements exposed to the environment. This can be achieved by applying a clear protective coating that not only creates a weather barrier, which prevents further deterioration of the surfaces, but also protects the surfaces against mechanical aggressions such as abrasion (dust), rubbing (during cleaning), or scratching. The objective of this work was to evaluate the relative performance of clear coatings: the acrylic varnish Incralac and a hybrid sol–gel coating, and some hard coatings (TiN and TiZrN) obtained by ionic deposition. The wear resistance of the three types of protective layers was investigated with linear scratch and abrasion tests. The results indicated great improvements in the wear resistance of brass by applying the hybrid sol–gel coating. The tested varnish, known for its high corrosion resistance, had very poor wear resistance. For hard coatings negative results observed for corrosion and abrasion resistance can be explained by the layer being too thin and porous. The hybrid sol–gel coating gives the best compromise in terms of tarnishing, corrosion (salt spray and atmospheric exposure), scratching, wear, application, aestheticism (coloration, brightness), and cost.

The Emission of Carbonyl Compounds during Thermal Processing of an Acrylic Polymer

Optimal conditions of heating for an acrylic varnish have been determined by a study with a Setaram apparatus (simultaneous TG-DTA). While the dry var nish underwent thermal decomposition, the carbonyl compounds emitted were adsorbed on silica cartridges and separated by high-performance liquid chromatography. The thermal decomposition up to 650 ° C and up to 350 ° C showed that formaldehyde and acetaldehyde were the predominant toxic car bonyl compounds. Acrolein was found only when the varnish was heated up to 650°C; it was not emitted when heating was limited to 350°C. These experi mental results are compared with analyses performed in the industrial sector.

The Emission of Carbonyl Compounds during Thermal Processing of an Acrylic Polymer

Optimal conditions of heating for an acrylic varnish have been determined by a study with a Setaram apparatus (simultaneous TG-DTA). While the dry varnish underwent thermal decomposition, the carbonyl compounds emitted were adsorbed on silica cartridges and separated by high-performance liquid chromatography. The thermal decomposition up to 650°C and up to 350°C showed that formaldehyde and acetaldehyde were the predominant toxic carbonyl compounds. Acrolein was found only when the varnish was heated up to 650°C; it was not emitted when heating was limited to 350°C. These experimental results are compared with analyses performed in the industrial sector.