Synthesis and characterization of metal functional polybenzoxazines

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Tezin Türü: Doktora

Tezin Yürütüldüğü Kurum: Orta Doğu Teknik Üniversitesi, Fen Edebiyat Fakültesi, Kimya Bölümü, Türkiye

Tezin Onay Tarihi: 2014

Öğrenci: TUĞBA LEKESİZ ORHAN

Eş Danışman: JALE HACALOĞLU, CEYHAN KAYRAN İŞÇİ

Özet:

Polybenzoxazines possessing excellent mechanical and physical properties has been developed to overcome the shortcomings associated with the use of traditional phenolics. Various approaches for performance improvement of polybenzoxazine were examined. These approaches include alloying with other high performance polymers, hybridization with inorganics, and designing of novel monomers as well as high molecular weight polymeric precursors. In the first part of this work, benzoxazines based on phenol and aniline or aniline derivatives namely aminopyridine, aminobenzonitrile and nitroaniline are synthesized and polymerized by curing the monomers systematically. In the second part of the work metal or metal ions are incorporated to benzoxazine monomers based on aminopyridine, aminobenzonitrile and nitroaniline. The structural and thermal characteristics of the polybenzoxazines and metal or metal ion functional polybenzoxazines are analyzed via FTIR, NMR, DSC, TGA and DP-MS techniques. The effects of curing program used and incorporation of metal and/or metal ion on structural and thermal characteristics of the polybenzoxazines are investigated. In general, the benzoxazines based on aniline or aniline derivatives are polymerized via ring opening of oxazine ring followed by attack of NCH2 groups to mainly para positions of phenol and aniline ring. The char yield and presence of chains that can only decompose at elevated temperatures mainly depend on extent of crosslinking and unsaturated linkages. Coordination of metal and/or metal ion to pyridine in case of aminopyridine based benzoxazine, to CN groups in case of aminobenzonitrile and finally to NO2 groups in case of nitroaniline cause drastic changes in structural and thermal characteristics of the polybenzoxazines produced. The coordination of metal or metal ion to the aromatic ring of the benzoxazine monomer promotes the evolution of amine or substituted amine groups which in turn causes an increase in the formation of unsaturated linkages but a decrease in the extent of crosslinking.