Synthesis and characterization of thermally stable camphor-based polyimide--clay nanocomposites

Authors : Murat YİĞİT, Turgay SEÇKİN, Beyhan YİĞİT, Süleyman KÖYTEPE

Pages : 182-194

Doi:10.3906/kim-1202-65

View : 18 | Download : 8

Publication Date : 0000-00-00

Article Type : Research Paper

Abstract :A new monomer was prepared from insert ignore into journalissuearticles values(1R,3S);-insert ignore into journalissuearticles values(+);-camphoric acid. Novel polyimide and polyimide--clay hybrid composites were developed from one-pot condensation reactions of this monomer and pyromellitic dianhyride. Polyimide-montmorillonite nanocomposites were prepared from solution of polyimide and with different weight percentages insert ignore into journalissuearticles values(1, 5, 10 wt %); of organo-modified montmorillonite insert ignore into journalissuearticles values(OM-MMT); using N-methyl-2-pyrrolidone insert ignore into journalissuearticles values(NMP); as aprotic solvent. The reactive organoclay was formed by using hexadecylpyridinium chloride as a swelling agent for silicate layers of montmorillonite. The polyimide--clay composites films insert ignore into journalissuearticles values(PI--MMT); were characterized by Fourier transform infrared spectroscopy, scanning electron microscopy insert ignore into journalissuearticles values(SEM);, and X-ray diffraction insert ignore into journalissuearticles values(XRD);. All composites were subjected to differential scanning calorimetry measurements for the purpose of examining Tg from all compositions. The clay content significantly influenced the thermal behavior of the polymeric films, such as glass transition and decomposition temperatures of polyimide--clay composites. The glass transition temperatures of the composites were higher than that of the original polyimide. Their thermal decomposition temperatures insert ignore into journalissuearticles values(Td = temperature at 5% mass loss); were measured via thermogravimetric analysis and showed that the introduction of clay into polymer backbones increased thermal stability. SEM, XRD, and the other conventional techniques were used for structural characterization. Dispersion of the modified clay in the polyimide matrix resulted in nanostructured material containing intercalated polymer between the silicate layers. The morphology and properties of PI nanocomposites greatly depend on the functional groups of the organic modifiers, synthesis procedure, and structure of polyimide because of the chemical reactions and physical interactions involved.
Keywords : Polyimide, nanocomposites, organoclay, clay dispersion