20.500.12556/RUL-161856 Vpliv postopkov predobdelave lesa in uporabe železovega(II) sulfata na staranje in kemijske spremembe lesa Effect of wood pre-treatment processes and the use of iron(II) sulphate on wood ageing and chemical changes Les je naravni material, ki se že vrsto let uporablja v različne namene. Trenutni trendi v arhitekturi in okoljevarstveni politiki so povzročili rast povpraševanja po vgradnji naravnega in nezaščitenega lesa na prostem. Les, izpostavljen zunanjim vplivom, sčasoma neenakomerno posivi, kar je lahko problematično tam, kjer veliko vlogo igra videz izdelka (npr. lesena fasada). Ena od rešitev je umetno staranje oziroma sivenje z železovimi ioni, ki omogoča enakomerno obarvanje, ki nato prehaja v naravno sivenje. Slabost tega postopka je, da ti odtenki niso povsem enaki naravno staranemu lesu. Če les pred nanosom železovih ionov predhodno staramo, površina razvije bolj naraven siv odtenek. V naši raziskavi smo ugotavljali, kako z različnimi postopki pospešenega staranja lesa vplivamo na njegov končni izgled po obdelavi z železovimi ioni in naravnem staranju. Postopki predobdelave so zajemali izpostavitev UV sevanju, spiranje in obdelavo s tanini. Po pospešenem staranju so barvne razlike naraščale sorazmerno s časom UV obsevanja, medtem ko proces spiranja ni igral večje vloge. Po obdelavi z železom so bile največje barvne razlike na preizkušancih, obdelanih s taninom. Po izpostavitvi na prostem se barvne razlike med posameznimi postopki predobdelave sčasoma zmanjšujejo. Pomemben je tudi vpliv vremena, saj je veliko sonca in dežja povzročilo občutno posvetlitev preizkušancev po 18. tednu zunanje izpostavitve. V tem času so se pojavile tudi prve glive modrivke, medtem ko smo jih na kontrolnih vzorcih opazili že prej. S FTIR analizo smo dokazali vpliv postopkov predobdelave in naravnega staranja na kemijsko sestavo površine. Wood has been used for various purposes for many millennia. Recent trends in architecture and environmental policies have increased the demand for natural, unprotected wood in outdoor applications. However, wood exposed to the elements tends to grey unevenly, which can be problematic for visually important applications like timber façades. One solution is artificial greying with iron ions, providing a uniform colour that later transitions to natural greying. However, these shades differ from naturally aged wood. If the wood is pre-aged before the iron ions are applied, the surface develops a greyer shade. In our study, we investigated how different accelerated ageing treatments affect the final appearance of wood after iron ion treatment and natural ageing. The pre-treatments included UV radiation, leaching and tannin treatment. After accelerated ageing, colour differences increased in proportion to the time of UV irradiation, while the leaching process did not play a significant role. After the iron ion treatment, the highest colour differences were observed on the tannin-treated samples. After outdoor exposure, the colour differences between the different pre-treatments decreased over time. The weather is also an important factor, as high levels of sunshine and rain resulted in a significant lightening of the specimens after 18 weeks of outdoor exposure. This is also when the first blue stain fungi appeared, whereas the control samples already showed them earlier. FTIR analysis proved the influence of pre-treatment and natural ageing processes on the chemical surface composition. staranje UV sevanje spiranje tanin železov(II) sulfat barvne spremembe ageing UV radiation leaching tannin iron(II) sulphate colour changes true false false [A. Kordiš] Slovenski jezik Angleški jezik Magistrsko delo/naloga 2024-09-15 07:18:21 2024-09-15 07:18:25 2024-09-18 03:22:35 0000-00-00 00:00:00 2024 0 0 0000-00-00 NiDoloceno NiDoloceno NiDoloceno 0000-00-00 0000-00-00 0000-00-00 630*841.4:813.6 245390 207587075 MAG_Kordis_Aljaz_2024.pdf MAG_Kordis_Aljaz_2024.pdf 1 8199B68826DA15AED7F393EC2F48C69B daacd6136dc3bc7eb280c7c05fe7ca84bed123a0305a71aa7c7275d76f5a39f1 d9b647d0-7321-11ef-b232-0050569b8976 https://repozitorij.uni-lj.si/Dokument.php?lang=slv&id=190842 Biotehniška fakulteta 0 0 0