Poly(azo-ether-imide) nanocomposite films reinforced with nanofibers electrospun from multi-walled carbon nanotube filled poly(azo-ether-imide)

A high molecular weight (27 x 10(3) gmol(-1)) poly(azo-ether-imide) has been fabricated in this study. Well-aligned poly(azo-ether-imide) fibers and poly(azo-etherimide)/multi-walled carbon nanotube nanofibers-based nanocomposite were then produced by electrospinning via self-reinforcement. Transmission electron microscopy showed that the poly(azo-ether-imide)-multi-walled carbon nanotube electrospun nanofibers were uniform and almost free of defects. Scanning electron microscopy indicated the wrapping of matrix over the bundles of nanofibrs. The as prepared electrospun nanofibers were utilized as homogeneous reinforcement to enhance the tensile strength and toughness of films. The tensile strength and tensile modulus of poly(azo-ether-imide) film reinforced with 3 wt% poly(azoether- imide)-multi-walled carbon nanotube nanofibers were 18% and 23% higher as compared to those of the poly(azo-ether-imide) film reinforced with 3 wt% neat poly(azo-ether-imide) nanofibers. The significant enhancement in the overall mechanical properties of the poly(azo-ether-imide)-multi-walled carbon nanotube nanofibers reinforced polyimide films was ascribed to good compatibility between the electrospun nanofibers and the matrix as well as high nanofiber orientation in the matrix. The homogeneous alignment of poly(azo-ether-imide)/multi- walled carbon nanotube nanofibers was also studied using scanning electron microscopy micrographs. Moreover, the thermal stability of poly(azo- ether- imide)/multi- walled carbon nanotube nanofibers reinforced polyimide was superior having 10% gravimetric loss at around 602-617 degrees C and glass transition temperature in the range of 241-263 degrees C relative to the neat polymer and poly(azo-ether-imide) nanofiber-based system. This study demonstrated the fabrication of high performance and high toughness polyimide nanocomposites by using this facile self-reinforcement method.