Multifunctional curing component for epoxidized novolac resin by grafting poly (amidoamine) on carbon nanotubes using a divergent method

Poly(amidoamine)-grafted carbon nanotube (CNTD) was synthesized and used as a multi-component curing agent for epoxidized novolac resin (ENR). This composite and curing agent can improve thermal stability of the resin due to its tubular graphitic core and also dendritic amino-functionalities. The ENR was cured in the presence of different amounts of CNTD. Then, the thermal degradation temperature and also char content of the products were compared with the ethylenediamine-cured ENR. Successful functionalization of oxidized carbon nanotubes with poly(amidoamine) was evaluated by Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, X-ray diffraction, and thermogravimetric analysis. According to the thermogravimetric analysis results, char content of ethylenediamine-cured ENR is 44.7% which increased to 54.6%, 55.5%, and 56.9% by the addition of 3, 5, and 8wt% of CNTD into the resin matrix. Also, addition of CNTD content increased thermal stability of the composites. The tubular structure of CNTD was observed by scanning and transmission electron microscopies.