Surface modification of birch and acetylated birch wood by silicone nanofilaments

التفاصيل البيبلوغرافية
العنوان:	Surface modification of birch and acetylated birch wood by silicone nanofilaments
بيانات النشر:	KTH, Byggnadsmaterial RISE Research Institutes of Sweden, Division Bioeconomy and Health, Material and Surface Design Stockholm, Sweden 2023
تفاصيل مُضافة:	Yin, Haiyan
نوع الوثيقة:	Electronic Resource
مستخلص:	The increasing awareness of sustainability motivates the development of building materials from renewable resources. The requirements of wood-based products with improved durability, for example, enhanced liquid repellence and UV and biological resistance, are still a challenge. Surface modification of wood by a superhydrophobic layer is one approach for counteracting the challenge. In this thesis, wood veneers of untreated and acetylated birch were surface-modified with fluorinated or non-fluorinated silicone nanofilaments in gas phase. Results demonstrated that the fluorine surface-modified birch (F-SMB) samples showed superamphiphobicity, i.e. a surface that repelled water, ethylene glycol and hexadecane with contact angles (CAs) greater than 150° and roll-off angles (ROAs) of less than 10°. Fluorine-free surface-modified birch and acetylated birch (SMB and SMAB) showed superhydrophobicity with static CA greater than 160° towards water and low ROA even for samples prepared with the shortest reaction time of 1 h. The surface-modified wood showed good wetting resistance analyzed by the multicycle Wilhelmy plate method. The SMB showed a lower water uptake than the acetylated wood while the SMAB showed the lowest water uptake, i.e. a pronounced increased water resistance, due to a combined effect of acetylation and surface modification. The silicone nanofilaments were not degraded after UV irradiation. Both the UV-irradiated SMB and SMAB still showed good wetting resistance with high static CAs and low water uptake. The UV-irradiated SMAB showed the lowest water uptake. The SMB and F-SMB showed good mold resistance with mold appearing later or with less intensity than those on the untreated birch due to the improved water resistance. All acetylated birch showed an even better mold resistance since the acetylation reduces the moisture absorption in the wood substance; whereas the surface modifications on acetylated birch played a slightly negative effect due to side Den ökande medvetenheten om hållbarhet motiverar utvecklingen av byggmaterial från förnybara resurser. Kraven på träbaserade produkter med förbättrad beständighet, till exempel förbättrad vätskeavvisning och UV- och biologisk beständighet, är fortfarande en utmaning. Ytmodifiering av trä med ett superhydrofobt ytskikt är ett sätt att tackla utmaningen. I denna avhandling ytmodifierades träfanér av obehandlad och acetylerad björk med fluorerade eller icke-fluorerade silikon-nanofilament i gasfas. Resultat visade att björkproverna som ytmodifierats med de fluorerade silikon-nanofilamenten (F-SMB) uppvisade superamfifobicitet, alltså ytor som stötte bort vatten, etylenglykol och hexadekan med kontaktvinklar (CA) större än 150° och avrinningsvinkel (ROA) på mindre än 10°. Proverna av björk och acetylerad björk som modifierats med de icke-fluorerade silikon-nanofilamenten (SMB och SMAB) uppvisade superhydrofobicitet med statisk CA större än 160° för vatten och låg ROA även för prover preparerade med den kortaste reaktionstiden på 1 timme. Det ytmodifierade träet uppvisade god vätningsbeständighet, analyserat genom flercykelmätningar med Wilhelmy-metoden. SMB visade ett lägre vattenupptag än det acetylerade träet medan SMAB visade det lägsta vattenupptaget, det vill säga en markant ökad vattenresistens, tack vare en kombinerad effekt av acetylering och ytmodifiering. Silikon-nanofilamenten bröts inte ned efter UV-bestrålning. Både den UV-bestrålade SMB och SMAB visade fortfarande god vätningsbeständighet med höga statiska CA och lågt vattenupptag. Den UV-bestrålade SMAB visade lägst vattenupptagningsförmåga. SMB och F-SMB visade god resistens mot mögelpåväxt som uppträdde senare eller med mindre intensitet än påväxten på den obehandlade björken tack vare den förbättrade vattenavvisningen. All acetylerad björk visade en ännu bättre mögelresistens eftersom acetyleringen minskade fuktupptagningen i träsubstansen; medan ytmodifierad acetylerad björk uppvisade något sämre möge QC 20230223
مصطلحات الفهرس:	Acetylated wood, surface modification, superhydrophobicity, plastron, wetting, silicone nanofilaments, UV irradiation, mold resistance, blue stain., Acetylerat trä, ytmodifiering, superhydrofobicitet, vätning, silikon-nanofilament, UV-bestrålning, mögelresistens, blånad., Wood Science, Trävetenskap, Other Civil Engineering, Annan samhällsbyggnadsteknik, Doctoral thesis, comprehensive summary, info:eu-repo/semantics/doctoralThesis, text
URL:	http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-323747 TRITA-ABE-DLT ; 235
الإتاحة:	Open access content. Open access content info:eu-repo/semantics/openAccess
ملاحظة:	application/pdf English
أرقام أخرى:	UPE oai:DiVA.org:kth-323747 0000-0002-9585-1961 urn:isbn:978-91-8040-479-2 1372210922
المصدر المساهم:	UPPSALA UNIV LIBR From OAIster®, provided by the OCLC Cooperative.
رقم الأكسشن:	edsoai.on1372210922
قاعدة البيانات:	OAIster

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