Cellulose nanocrystals effect on the stabilization of polyacrylonitrile composite films

Abstract

The stabilization kinetics of polyacrylonitrile-co-methacrylic acid (PAN-co-MAA) and cellulose nanocrystal (CNC) composite films were studied with up to 40 wt% CNC loading using differential scanning calorimetry (DSC). It was determined that the addition of CNC reduced the activation energy of the polyacrylonitrile cyclization reaction by 16% irrespective of the CNC loading in the range of 5–40 wt%. There was also a development of a new exothermic peak in the PAN-co-MAA/CNC composite films after cyclization not seen in the neat PAN-co-MAA and neat CNC samples, indicating a different set of reactions occurring. Fourier transform infrared spectroscopy (FTIR) and wide-angle X-ray diffraction (WAXD) demonstrated that CNC within the PAN-co-MAA/CNC composite films were more thermally stable than the neat CNC film. Additionally, for the composite films, their reaction rate constants for cyclization and oxidations were found to be higher than neat PAN-co-MAA at certain temperatures, indicating that the addition of CNC into PAN-co-MAA can reduce the energy needed for stabilization.