Synthesis, morphology investigation and thermal mechanical properties of dopamine-functionalized multi-walled carbon nanotube/poly(amide-imide) composites

Here, poly(amide-imide) (PAI) composites containing multi-walled carbon nanotubes (MWCNT) were synthesized with solution casting method. To improve the dispersion and compatibility with the polymer matrix the MWCNT was surface-modified with dopamine biomolecule under microwave irradiation. The prepared dopamine-functionalized MWCNT (MWCNT-Dop) was characterized for their structure, morphology, and thermal behavior employing Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), thermogravimetric analysis, field emission scanning electron microscopy (FE-SEM), and transmission electron microscopy (TEM). The results consistently confirmed the formation of dopamine functionalities on MWCNT. The MWCNT-Dop/PAI hybrid films were also characterized extensively using FT-IR and XRD techniques. The microstructure of the composites was studied by FE-SEM and TEM, in terms of the dispersion state of the nanotubes and the polymer-nanotube interface. The thermal behavior and mechanical properties of the resultant composites were also studied. In comparison with neat PAI, the MWCNT-Dop reinforced composites posses higher thermal stability, tensile strength and Young's modulus.