Borik asit ve polikaprolakton modifikasyonunun ahşabın biyolojik dayanım ve boyut stabilizasyonu ile bor yıkanmasına etkisi
Küçük Resim Yok
Tarih
2019
Yazarlar
Dergi Başlığı
Dergi ISSN
Cilt Başlığı
Yayıncı
Bursa Teknik Üniversitesi
Erişim Hakkı
info:eu-repo/semantics/openAccess
Özet
Bu çalışmada ahşap malzemenin dış mekanlardaki kullanımını arttırmak için sağlığa ve çevreye olumsuz etkilerinden dolayı geleneksel emprenye maddelerine getirilen kısıtlamalar nedeniyle, bor ve polikaprolakton esaslı koruma sistemlerinin geliştirilmesi amaçlanmıştır. Borlu emprenye bileşikleri hem masif ahşap hem de ahşap bazlı kompozit malzemelerin korunmasında kullanılan oldukça önemli maddeler olup, hem ahşabı degrade eden mantarlara hem de böceklere karşı yüksek oranda toksik özellik göstermektedir. Bu yüzden borlu emprenye bileşikleri ahşap esaslı malzemeleri su ile temasta olmayan toprak üstü yapılarda korumak için önemli kimyasal maddeler olarak kabul edilmektedir. Ancak dış ortam koşullarında kullanılan emprenye edilmiş malzeme içindeki borlu bileşikler yıkanmak suretiyle ahşaptan uzaklaşabilir ve zaman içerisinde ahşap malzemenin biyolojik dayanım özellikleri kaybolur. Diğer yandan çevre dostu yöntemler içerisinde kabul gören ahşabın kimyasal modifikasyonu da malzemenin hem boyutsal kararlılığını artıran hem su alımını azaltan, çoğu durumda da biyolojik bozunmaya karşı dayanımını arttıran işlemler olarak karşımıza çıkmaktadır. Asetilleme ve furfurilasyon gibi ticari boyutta uygulanan birkaç yöntem mevcuttur. Yeni, düşük maliyetli, daha etkili yöntemler de akademik olarak çalışılmaktadır. Polikaprolakton modifikasyonu da yeni bir yöntem olarak literatüre girmiş, ahşabın boyutsal stabilitesi ve su iticiliğini kayda değer oranda arttırdığı tespit edilmiştir. Hem biyobozunur bir polimer olması, hem de hidrofobik olması, polikaproktonu çevre dostu ve etkili bir modifikasyon kimyasalı olmasının önünü açmaktadır. Borlu bileşikler ve kimyasal modifikasyon işleminin beraber yürütüldüğü ve ahşaba uygulandığı az sayıda çalışma literatürde vardır. Bu çalışmada, borik asit ile hücre çeperi içine girerek kovalent bağ yapabilen hidrofobik polikaprolakton polimeri çeşitli varyasyon ve yöntemler ile ahşap malzemeye uygulanmıştır. Böylece istenen borlu bileşikler polimer yardımıyla hücre çeperi içine hapsedilerek borun yıkanmasının önlenmesi/azaltılması ve biyolojik dayanımın arttırılması hedeflenmiştir. Deney sonucunda modifiye edilmiş ahşap malzemenin kimyasal ve fiziksel olarak karakterize edilmiş, özellikle modifikasyonun ve borik asitin etkinliğini anlamak için çürüklük testlerine tabi tutulmuş, borlu bileşiğin fiksasyonunun sağlanıp sağlanmadığını test etmek için de ICP-OES analizi ile bor tayini yapılmıştır. Ayrıca modifiye ahşabın kimyasal özellikleri FTIR spektroskopisi ile, morfolojik değişimleri de taramalı elektron mikroskobu (SEM) ile incelenmiştir.
In this study, due to the restrictions imposed on traditional impregnation materials for their negative effects on health and environment, boric acid and polycaprolactone based protection systems were investigated in order to improve wood properties for outdoor use. Boron compounds are very important substances in the protection of both wood and wood based composite materials and show high toxicity against wood-degrading mushrooms and other bio-organism. Therefore, boron compounds are considered to be important chemicals to protect wood based materials in above ground structures not in contact with water. But boron compounds in the impregnated material used in outdoor conditions can be removed from the wood by washing and in time the biological durability properties of the wood material are lost. On the other hand, the chemical modification of the wood, which is admitted within the environmentally friendly methods, is able to increase the dimensional stability of the material and decrease the water uptake, and in many cases increase the resistance against biodegradation. There are several commercially available methods such as acetylation and furfurylation. New, low cost, more effective methods are also studied in academic research. The modification of polycaprolactone has also entered the literature as a novel method, and it has been determined that the dimensional stability and water repellency of wood were significantly increased. Being both a biodegradable polymer and being hydrophobic, polycaprolactone paves the way for an environmentally friendly and effective modification reagent. There are few studies in the literature where boron compounds and chemical modification processes are carried out together and applied to wood. In this study, the epsilon-caprolactone monomer was grafted into the cell wall and the boric acid has been applied together to wood material with various variations and methods. Thus, the boron compound was planned to provide bio-resistance to wood by fixing it into the cell wall with the help of polymer. At the end of the experiment, the modified wood material was chemically and physically characterized, and it was subjected to decay tests to understand the effectiveness of the modification and boric acid. Boron analysis was performed by ICP-OES analysis to test whether the fixation of the boron compound was achieved. In addition, the chemical properties of the modified wood were investigated by FTIR spectroscopy and the morphological changes were illuminated by scanning electron microscopy (SEM). On the other hand, it is important in terms of cost of the modification processes that the various production methods applied provide the most optimum and successful method.
In this study, due to the restrictions imposed on traditional impregnation materials for their negative effects on health and environment, boric acid and polycaprolactone based protection systems were investigated in order to improve wood properties for outdoor use. Boron compounds are very important substances in the protection of both wood and wood based composite materials and show high toxicity against wood-degrading mushrooms and other bio-organism. Therefore, boron compounds are considered to be important chemicals to protect wood based materials in above ground structures not in contact with water. But boron compounds in the impregnated material used in outdoor conditions can be removed from the wood by washing and in time the biological durability properties of the wood material are lost. On the other hand, the chemical modification of the wood, which is admitted within the environmentally friendly methods, is able to increase the dimensional stability of the material and decrease the water uptake, and in many cases increase the resistance against biodegradation. There are several commercially available methods such as acetylation and furfurylation. New, low cost, more effective methods are also studied in academic research. The modification of polycaprolactone has also entered the literature as a novel method, and it has been determined that the dimensional stability and water repellency of wood were significantly increased. Being both a biodegradable polymer and being hydrophobic, polycaprolactone paves the way for an environmentally friendly and effective modification reagent. There are few studies in the literature where boron compounds and chemical modification processes are carried out together and applied to wood. In this study, the epsilon-caprolactone monomer was grafted into the cell wall and the boric acid has been applied together to wood material with various variations and methods. Thus, the boron compound was planned to provide bio-resistance to wood by fixing it into the cell wall with the help of polymer. At the end of the experiment, the modified wood material was chemically and physically characterized, and it was subjected to decay tests to understand the effectiveness of the modification and boric acid. Boron analysis was performed by ICP-OES analysis to test whether the fixation of the boron compound was achieved. In addition, the chemical properties of the modified wood were investigated by FTIR spectroscopy and the morphological changes were illuminated by scanning electron microscopy (SEM). On the other hand, it is important in terms of cost of the modification processes that the various production methods applied provide the most optimum and successful method.
Açıklama
Fen Bilimleri Enstitüsü, Biyokompozit Mühendisliği Ana Bilim Dalı
Anahtar Kelimeler
Ağaç İşleri, Wood Products, Ormancılık ve Orman Mühendisliği
