Methacrylic resin for protection of wood from discoloration by mould growth and weathering

Abstract

The discoloration of uncoated wood surfaces in both outdoor and indoor use in non-heated spaces has become an increasing problem in European timber constructions due to the use of less toxic substances for protection and also changes in outdoor climate conditions, necessitating the use of protective coatings. To investigate the effect of methyl methacrylic (MMA) resin for the protection of wood from discoloration and mould growth, resin-treated wood surfaces were studied in a laboratory-scale mould test, as well as in an outdoor weathering test. Non-modified Scots pine and Norway spruce were used, and some of the test materials were also thermally modified. The resin suppressed mould growth for the laboratory-scale experiments. The protective effect was considerably reduced for outdoor tests. The MA resin did not effectively prevent the wood from greying from ultraviolet (UV) radiation exposure; there was some protective effect detected on the pine. The Fourier transform infrared (FTIR) spectra of weathered specimens showed a reduction of lignin-associated absorption bands for all treatments, which corresponded to the UV degradation and greying of the wood surface. It is suggested that MMA resin may provide adequate protection against mould growth on wood without direct exposure to rain and sunshine (e.g., attics, basements, etc).

Biomonitoring of benzophenones in guano samples of wild bats in Poland

“…The possibility of such contact and/or inhalation exposure to BPs is confirmed by previous studies that described the presence of benzophenones in indoor dust and air [ 21 , 90 ]. The exposure of bats in the summer colony to BPs is also promoted by the use of these substances as ingredients of paints and wood impregnations [ 91 , 92 ]. However, bat exposure to BPs through the gastrointestinal tract seems to be more important when guano samples are considered.…”

Trends in Chemical Wood Surface Improvements and Modifications: A Review of the Last Five Years

“…Thermochromic wood veneers were prepared by Zhu et al through the ultrasonic impregnation of a thermochromic dye and a color developer [242]. The treated wood, which was very dark, could return to its original color between 28 • C and 38 • C, while the discoloration was reversible between 34 • C and 22 • C. Other publications reported the surface impregnation of chemicals to decrease the wettability [57], flammability [243], mold [244,245] and mildew [246] degradation, and dimensional instability [247] of various wood substrates.…”

“…Accordingly, these coating methods must allow for working in large batches in order to keep a good production rate. Brushing and dipping were also used to perform the surface impregnation of different protective agents into wood substrates, with similar limitations [238][239][240][241]244,246,247]. A quite different, yet interesting method was presented by Volokitin et al, who modified pine and birch with a thermal plasma to produce only a layer of thermo-modified wood [193].…”