20.500.12556/RUL-126628 Photostabilization of rubberwood using cerium oxide nanoparticles Characterization and colour changes Fotostabilizacija lesa kavčukovca z nanodelci cerijevega dioksida karakterizacija in spremembe barve Light induced darkening and deterioration of wood used outdoors is undesirable. Photoprotection of wood could be achieved by using additives that reflect or absorb harmful radiation responsible for degradation. Nano metal oxides have strong absorption in the UV range of solar radiation and good transparency in the visible region. They offer unique benefits in protecting coatings and coated substrates from being degraded by UV radiation. However, to exploit the properties of nanoparticles, homogenous dispersion without agglomeration is necessary. In the present work, the photostabilization of rubberwood surfaces coated with cerium oxide (CeO2) was studied. The nanoparticles were surface functionalized with an organic alkoxy silane (3-glycidyloxypropyltrimethoxy silane) to improve the homogenous distribution in coatings, and the modified nanoparticles were dispersed in isopropanol and polyurethane (PU) coating. Rubberwood surfaces coated with dispersed nanoparticles (concentration 0.5 % to 6 % w/v) were exposed to a fluorescent UVA light source (λ=340 nm) at 60 °C in an accelerated weathering tester for 500 h and 1000 h. Colour changes due to UV light exposure were monitored using a spectrocolourimeter. Dispersion of CeO2 nanoparticles in PU coatings (concentration >2 %) restricted the photoyellowing of wood polymers. Degradacija in potemnitev lesa, ki je v uporabi na prostem, je nezaželena. Les je pred učinki svetlobe možno zaščititi z dodatki, ki odbijajo ali absorbirajo škodljivo sevanje, ki povzroča njegovo razgradnjo. Nano kovinski oksidi izkazujejo močno absorpcijo svetlobe v UV območju sončnega sevanja in dobro transparentnost v vidnem območju. Zato ponujajo edinstvene prednosti pri zaščiti premazov in površinsko obdelanih substratov, ki so občutljivi na UV sevanje. Vendar pa je za izkoriščanje zaščitnih lastnosti nanodelcev potrebna njihova homogena disperzija, tako da se ne tvorijo aglomerati. V tem prispevku poročamo o raziskavah fotostabilizacije površin lesa kavčukovca z nanodelci cerijevega dioksida (CeO2). Nanodelci so bili površinsko funkcionalizirani z organskim alkoksi silanom (3-glicidiloksi propiltrimetoksi silan) za izboljšanje homogene porazdelitve v premazih. Modificirane nanodelce smo dispergirali v izopropanolu in v poliuretanskem (PU) premazu. Površine lesa kavčukovca, na katere smo nanesli dispergirane nano-delce (koncentracija od 0,5 % do 6 % m/v), smo v napravi za umetno pospešeno staranje za 500 ur in 1000 ur in pri 60 °C izpostavili UVA svetlobi (% = 340 nm). Barvne spremembe zaradi izpostavitve UV svetlobi smo spremljali s kolorimetrom. Disperzija nanodelcev CeO2 v PU premazih (koncentracija >2 %) je zmanjšala foto-rumenenje lesnih polimerov. Rubberwood PU coating nanoparticle Cerium oxid photostability colour stability kavčukovec PU premaz nanodelci cerijev dioksid fotostabilnost stabilnost barv true false true Angleški jezik Slovenski jezik Neznano 2021-04-29 08:47:04 2021-04-29 08:47:05 2023-02-15 09:37:26 0000-00-00 00:00:00 2020 0 0 Str. 57-70 št. 1 Letn. 69 2020 0000-00-00 Zaloznikova Objavljeno NiDoloceno 0000-00-00 0000-00-00 0000-00-00 630*8 0024-1067 10.26614/les-wood.2020.v69n01a06 20473347 RAZ_Srinivas_Kavyashree_2020.pdf RAZ_Srinivas_Kavyashree_2020.pdf 1 5036B07047FD37EF2D966D28A2A29455 88bbbfaf5eab2773937bbff3aba8127d6122943128b7e7f799cecdd899386fae a8c7f375-a8b7-11eb-a523-00155dcfd717 https://repozitorij.uni-lj.si/Dokument.php?lang=slv&id=142632 https://journals.uni-lj.si/les-wood/article/view/12144 0 b1b8e1be-a8b6-11eb-a523-00155dcfd717 https://repozitorij.uni-lj.si/Dokument.php?lang=slv&id=142631 Biotehniška fakulteta Les 0 0 0