20.500.12556/RUL-61599 Zaščita mahagonijevega lesa pred diskoloracijami Prevention of discolourations of mahogany wood The massive wood and plywood samples of African mahogany (Khaya sp.) were exposed to various illumination conditions. The largest changes of colour were exhibited after irradiation with UV light. As stated by FT-IR spectroscopy, exposure to UV light caused chemical changes of lignin and hemicellulose. In order to decrease the problem of fast discolourations of boat interior furniture elements, made of mahogany wood, already during production process, we tested preventive effectiveness of 17 different alkyd or acrylic polyurethane (PU) coatings. It was found out, that high sensitivity of PU coatings and PU finished mahogany plywood could be diminished by selection of appropriate UV-protecting additives. Although the protective coatings after application changed the colour of mahogany wood substantially, this remained relatively stable afterwards. Therefore, annoying discolorations of furniture made of mahogany wood do not appear during utilisation. Vzorce iz masivnega lesa in vezane plošče lesa afriškega mahagonija (Khaya sp.) smo izpostavili različnim svetlobnim pogojem. Največje spremembe barve so se pojavile po obsevanju z UV svetlobo, ki povzroča kemijske spremembe lignina in tudi hemiceluloze kar smo ugotovili iz nihajnih (FT-IR) spektrov. Da bi omilili hitre diskoloracije notranje opreme plovil iz mahagonijevega lesa, do katerih prihaja že med proizvodnjo, smo preverili zaščitno učinkovitost sedemnajstih različnih poliuretanskih premaznih sistemov na alkidni in akrilni osnovi. Ugotovili smo, da je visoko barvno občutljivost poliuretanskih premazov in premazanega mahagonijevega lesa možno bistveno izboljšati z izbiro primernih dodatkov, ki premaz in les ščitijo pred UV žarki. Premazni sistem sicer močno spremeni barvo mehansko obdelanega mahagonijevega lesa, vendar pa se nato barva med procesom proizvodnje in uporabe bistveno ne spreminja več, tako da barvni madeži ne nastajajo, morebitne naknadne manjše barvne spremembe pa za uporabnike niso moteče. afriški mahagoni Khaya sp. UV svetloba barva diskoloracija nihajni (FT-IR) spektri poliuretanski premaz African mahogany UV light colour discolouration FT-IR spectra polyurethane coating true false false Zveza društev inženirjev in tehnikov gozdarstva in lesarstva Slovenije Slovenski jezik Angleški jezik Delo ni kategorizirano 2015-07-10 19:04:47 2015-07-10 19:04:47 2022-08-01 12:37:03 0000-00-00 00:00:00 2004 0 0 Str. 278-282 št. 9 Let. 56 2004 0000-00-00 NiDoloceno NiDoloceno NiDoloceno 0000-00-00 0000-00-00 0000-00-00 674.006:630*174 0024-1067 1224329 13940224 RAZ_Tomazic_Miro_2004.pdf RAZ_Tomazic_Miro_2004.pdf 1 E36BEFCF5FD968A436BACCABDF99852E 85dd16bfdd6aa6cdf31d7a1c15b02fa8dbb823a839631eeac31db4b08c3e7cdb 2ad98b98-5699-11ec-abdb-00155dcfd717 20.500.12556/rul/84fe4e91-e018-49b9-b74e-00c581356665 https://repozitorij.uni-lj.si/Dokument.php?lang=slv&id=151853 http://www.dlib.si/details/URN:NBN:SI:DOC-KU2E9UK8 1 https://repozitorij.uni-lj.si/Dokument.php?lang=slv&id=61610 Biotehniška fakulteta Les 0 0 0