Preparation and properties evaluation of polyimide-matrix nanocomposites reinforced with glutamine functionalized multi-walled carbon nanotube

l-glutamine-grafted multi-walled carbon carboxylic acid nanotube (denoted as l-Gl-MWCNT) and polyimide-matrix l-Gl/MWCNT (l-Gl-MWCNT/PI) were prepared by in situ polymerization and solution-blending processes. The functionalization process was one-pot, fast, and simple, and resulted in a high degree of functionalization as well as dispersibility in organic solvents. The resulting materials were characterized by Fourier transform infrared spectroscopy, thermogravimetric analysis, X-ray diffraction, high-resolution transmission electron microscopy, and field-emission scanning electron microscopy. According to the microscopic characterizations, the MWCNTs are homogeneously dispersed in the composites. The thermal stability of the films containing Gl-MWCNTs was improved as the nanotube content increased from 5 to 15 wt% due to the improved interfacial interaction between the PI matrix and surface-modified MWCNTs.