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Surface changes of beech and pine wood under the influence of UV radiation
Názov Surface changes of beech and pine wood under the influence of UV radiation Aut.údaje Anton Geffert, Jarmila Geffertová, Eva Výbohová Autor Geffert Anton TUZDFCHTD - Katedra chémie a chemických technológií Spoluautori Geffertová Jarmila TUZDFCHTD - Katedra chémie a chemických technológií Výbohová Eva TUZDFCHTD - Katedra chémie a chemických technológií Zdroj.dok. Acta Facultatis Xylologiae Zvolen : vedecký časopis Drevárskej fakulty. Vol. 62, no. 2 (2020), s. 5-18. - Zvolen : Technická univerzita vo Zvolene, 2020 Poznámky Lit. Jazyk dok. angličtina Krajina Slovenská republika Systematika 674.031.632.2 630*81 674.032.475.4 52-74 535-31 54-76 543.2 Heslá bukové drevo - beech wood * borovicové drevo - pine wood * UV žiarenie - UV-radiation ultraviolet radiation * chemické analýzy - chemical analyses * farebný priestor CIE L*a*b* - CIE L*a*b* colour space CIELAB * ATR-FTIR spektroskopia - ATR-FTIR spectroscopy * degradácia lignínu - lignin degradation * karbonyly - carbonyls Anotácia The influence of UV radiation on two different types of wood –European beech (Fagus sylvaticaL.) and Scots pine (PinussylvestrisL.) was studied. The chemical composition of the original wood of the monitored woods (TEE, holocellulose, cellulose and lignin) was determined by standard analytical procedures. Changes in color characteristics (brightness, lightness L*, green-red coordinate a*, blue-yellow coordinate b* and total color difference ∆E*) were measured at the irradiation times of 30, 60, 90, 120 and 150 minutes. Chemical changes in the surface layers of irradiated wood were monitored by ATR-FTIR spectroscopy. Chemical analysis of the monitored wood samples showed higher content of cellulose, lignin and extractives and at the same time lower content of holocellulose and also hemicelluloses in pine wood than in beech wood, which affected the differences in the color changes of irradiated wood. More significant color changes were observed in pine wood compared to beech wood. A decrease in brightness was 37% of the absolute value for pine and 31% for beech, adecrease in lightness L*was 11% for pine and 9.7% for beech, and the total color difference ∆E*was 15.0 for pine and 11.3 for beech. The biggest color changes of color characteristics were recorded after the first 30 minutes of irradiation. The changes in the FTIR spectra of the surface of the irradiated wood showed that UV radiation caused the degradation of lignin and the formation of conjugated and unconjugated carbonyls and quinoid structures responsible for yellowing the wood surface. A decrease in the ratio of the absorbance A1510/A1370 (lignin / carbohydrates) was most significant after the first 30 minutes of irradiation (30% for pine and 43% for beech). However, anincrease in carbonyl content was more significantin pine (3-fold increase) compared to beech(2-fold increase). The dependence of the ratio of "relative" lignin absorbances and carbonyls on the total color difference ∆E*in both monitored woods showed a linear increasing trend in the case of carbonyls and a slightly decreasing trend in the case of lignin. URL https://df.tuzvo.sk/sites/default/files/01-02-20_0.pdf Kategória publikačnej činnosti ADN Báza dát xcla - ČLÁNKY Druh dok. RBX - rozpis článkov z periodík Odkazy PERIODIKÁ-Súborný záznam periodika Zväzky 2020: 1-2 
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