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Okoljsko sprejemljivejši načini modifikacije lesa za izboljšanje mehanskih lastnosti in požarne odpornosti
ID Leskovar, Jan (Author), ID Skalar, Tina (Mentor) More about this mentor... This link opens in a new window

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Abstract
Les je material, ki se pogosto uporablja v proizvodnji in gradbenem sektorju zaradi svojih izjemnih mehanskih lastnosti, fleksibilnosti, majhne gostote in cene. Sestavljen je iz celuloze, lignina in hemiceluloze, majhen delež predstavljajo še druge komponente, kot so polifenoli, tanini, voski in škrob. Njegove lastnosti lahko prilagajamo, glede na okolje v katerem ga uporabimo, s pomočjo raznih kemijskih metod, kot so mineralizacija, lesno premazovanje in toplotna obdelava. Pri mineralizaciji gre za impregnacijo minerala v lesno mikrostrukturo. S svojo vezavo lahko minerali spremenijo lastnosti lesa, na primer mehanska odpornost ali pa zavirajo gorenje. Pri termični modifikaciji les obdelamo pri visoki temperaturi, s tem lahko dosežemo boljšo dimenzijsko stabilnost, izboljšamo odpornost lesa proti gnitju, poslabšajo pa se mehanske lastnosti. Zaradi tega je potrebno paziti, kje uporabimo termično modificiran les. Les lahko premažemo z barvami, lazurami ali laki, ti ga lahko ali s prodiranjem v celično steno, ali pa s tvorbo filma na površini lesa zaščitijo. Tako postane odpornejši proti gorenju. V gradbeništvu se za spajanje različnih lesenih delov uporablja lepljenje. Pri tem je pomembno, da les ohrani stik v različnih okoljih, kar pomeni uporaba ustrezno močnih lepil. Ker les lahko po modifikaciji spremeni svoje mehanske lastnosti, je pomembno, da poznamo njegove mehanske lastnosti. Določimo jih lahko s standardnimi metodami. Glavni problem lesa je njegova gorljivost, zato ga je treba ustrezno zaščititi in zmanjšati možnost gorenja v požarno nevarnih situacijah. To storimo lahko predvsem z mineralizacijo ali lesnim premazovanjem. V diplomskem delu so raziskani tovrstni načini modifikacije, ki so ekološko bolj primerni in trajnostni. To so na primer mineralizacija s kalcijevim karbonatom ali struvitom, premazovanje z večfunkcionalnim premazom, ki je osnovan na prepletenem mrežnem sistemu CO₂-poliuretana in benzoksazina, lahko pa tudi pripravimo bioinspirirane mineralizirane lesne hidrogelne kompozite.

Language:Slovenian
Keywords:les, mineralizacija, termična modifikacija, lesni premazi, lepila, zaviranje gorenja
Work type:Bachelor thesis/paper
Typology:2.11 - Undergraduate Thesis
Organization:FKKT - Faculty of Chemistry and Chemical Technology
Year:2023
PID:20.500.12556/RUL-149485 This link opens in a new window
COBISS.SI-ID:169134339 This link opens in a new window
Publication date in RUL:07.09.2023
Views:871
Downloads:78
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Secondary language

Language:English
Title:Sustainable modification methods for improving the mechanical and fire-resistant properties of wood
Abstract:
Wood is a material widely used in manufacturing and construction due to its excellent mechanical properties, flexibility, low density and low cost. It is composed of cellulose, lignin and hemicellulose with a small amount of other components such as polyphenols, tannins, waxes and starch. Its properties can be adapted to the environment in which it is used through various chemical processes such as mineralization, wood coating and heat treatment. Mineralization is the impregnation of the wood structure with a mineral that, through its bonding, can modify the wood's properties, such as mechanical strength or flame resistance. Thermal treatment involves treating the wood at high temperatures, which can improve dimensional stability and rot resistance, but in most cases degrades mechanical properties. Wood can be coated with paints, varnishes, or stains that can protect the wood either by penetrating the cell wall or by forming a film on the wood surface. A wood coating can make the wood more resistant to burning. When gluing wood in construction, it is important that the wood remains in contact in different environments, that we use a strong enough adhesive for wooden beams, but we can also use weaker adhesives when assembling furniture. Wood can change its mechanical properties after modification. It is important we know its mechanical properties, they are determined by standardized methods. The main problem with wood is its flammability. It must be properly protected to reduce the risk of fire in situations with high fire risk. This can be done mainly by mineralization or wood coating, and in my work I have mainly explored more ecological and sustainable methods. These include, for example, mineralisation with calcium carbonate or struvite, coating with a multifunctional coating based on an interpenetrating network system of CO₂-polyurethane and natural bio-based benzoxazine or preparing bioinspired mineralized wood hydrogel composites.

Keywords:wood, mineralisation, thermal modification, wood coating, wood adhesives, flame retardancy

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