Publication: Kendi kendini onarabilen poliüretan nanokompozit kaplamaların sentezi ve karakterizasyonu
Abstract
Nanokompozitler, mukavemet, sertlik, termal kararlılık ve hafiflik bakımından üstünözelliklere sahip olması gibi özellikleriyle verimlilik ve sürdürülebilirliği artırmak içinpek çok uygulama alanında aranan malzemeler olarak öne çıkmaktadır. Buna karşın,nanokompozitler mezoskopik hasar (örneğin, mikro çatlaklar ve kavitasyon), bozulma veyüzey çizikleri gibi dezavantajlara sahiptir. Kendiliğinden iyileşmenin polimernanokompozitlerine uygulanması, elektronik, enerji, nakliye ve kaplamalar gibi birkaççok işlevli uygulama için sürdürülebilir, daha güvenli ve daha uzun ömürlü materyallereyönelik yeni yönergeler sunmaktadır. Esneklik, kolay işleme, hafiflik ve adapte olma gibidoğal özelliklerinden dolayı çeşitli uygulamalar için çeşitli polimer esaslı malzemelerkullanılmıştır. Bununla birlikte, sentezlenmiş nanokompozitlerde çatlak oluşumu,polimer ve polimer kompozit sistemlerde görülenlere kıyasla çok kritik problemlerarasındadır.Bu tez çalışmasında, kendini onarma özelliğine sahip grafen oksit – poliüretan esaslınanokompozit malzemeler geliştirilmiştir. Poliüretan nanokompozit kaplamanınmikrokapsüllenmiş azid – alkin siklo katılma reaksiyonu ile oluşan çatlakları onarmasıyoluyla kendini tamiri incelenmiştir. Alkoksisilan modifiye poliüretan prepolimeri veperflorooktil alkoksisilanlarla birlikte susuz sol-jel yöntemiyle nanokompozit kaplamalarhazırlanmıştır. Ardından kendini onarma özelliğini sağlayan alkin fonksiyonel grafenoksit sentezi gerçekleştirilmiş ve çok fonksiyonlu azid içeren polivinilformalmikrokapsüller hazırlanmıştır. Poliüretan nanokompozit malzemeler içerisine eklenen bubileşenlerle kendini onarabilen kaplamalar hazırlanmıştır. Hazırlanan serbest filmlerinDSC, TGA, SEM ve korozyon ölçümleri yapılarak karakterize edilmiştir. Kaplamayüzeyinde hasar oluştuktan sonra, azid alkin katılması reaksiyonları sonrasındamalzemenin kendini onarmasını takiben mekanik mukavemetini geri kazanımı daincelenmiştir.
Nanocomposites stand out as promising materials in many applications in order toincrease productivity and sustainability with their properties such as strength, hardness,thermal stability and lightness. However, nanocomposites have disadvantages such asmesoscopic damage (eg, microcracks and cavitation), distortion and surface scratches.The application of self-healing to polymer nanocomposites provides new guidelines forsustainable, safer, and longer-lasting materials for a number of multifunctionalapplications, such as electronics, energy, transport and coatings. Various polymer-basedmaterials have been used for different applications due to their natural properties such asflexibility, easy processing, lightness and adaptability. The crack formation innanocomposites is one of the critical problems compared to those seen in polymer andpolymer composite systems.In this thesis, a new self-healable graphene oxide - polyurethane based nanocompositematerial was developed. The self-healing of the polyurethane coating was investigatedvia the microcapsulated azide - alkyne cycloaddition reaction to heal cracks.Nanocomposite coatings were prepared by an anhydrous sol-gel process using thealkoxysilane modified polyurethane prepolymer and perfluorooctylalkoxysilane. Thenfor the self-healing ability both the alkyne functional graphene oxide and multifunctionalazide containing polyvinylformal microcapsules were synthesized. Finally, incorporationof these components into nanocomposite formulation, self-healable coatings werefabricated. The prepared films were characterized by DSC, TGA, SEM and corrosionmeasurements. The self-healing mechanism of the material was investigated that are ableto recover their fundamental properties including mechanical strength after the damageoccurred.
Nanocomposites stand out as promising materials in many applications in order toincrease productivity and sustainability with their properties such as strength, hardness,thermal stability and lightness. However, nanocomposites have disadvantages such asmesoscopic damage (eg, microcracks and cavitation), distortion and surface scratches.The application of self-healing to polymer nanocomposites provides new guidelines forsustainable, safer, and longer-lasting materials for a number of multifunctionalapplications, such as electronics, energy, transport and coatings. Various polymer-basedmaterials have been used for different applications due to their natural properties such asflexibility, easy processing, lightness and adaptability. The crack formation innanocomposites is one of the critical problems compared to those seen in polymer andpolymer composite systems.In this thesis, a new self-healable graphene oxide - polyurethane based nanocompositematerial was developed. The self-healing of the polyurethane coating was investigatedvia the microcapsulated azide - alkyne cycloaddition reaction to heal cracks.Nanocomposite coatings were prepared by an anhydrous sol-gel process using thealkoxysilane modified polyurethane prepolymer and perfluorooctylalkoxysilane. Thenfor the self-healing ability both the alkyne functional graphene oxide and multifunctionalazide containing polyvinylformal microcapsules were synthesized. Finally, incorporationof these components into nanocomposite formulation, self-healable coatings werefabricated. The prepared films were characterized by DSC, TGA, SEM and corrosionmeasurements. The self-healing mechanism of the material was investigated that are ableto recover their fundamental properties including mechanical strength after the damageoccurred.