Polypyrrole inter-layered low temperature curing benzoxazine matrices with enhanced thermal and dielectric properties

In the present work, curing reaction of benzoxazine was studied with the incorporation of different weight percentage of polypyrrole (PPy). Conventional benzoxazine derived from Bisphenol-F, aniline (BF-a) and bio-based benzoxazine derived from cardanol, furfurylamine (C-f) were synthesized and studied. Significant change in curing temperature (Tp) was observed with the addition of PPy to both C-f and BF-a monomers. With the incorporation of 5 wt% PPy, the Tp of C-f significantly reduced from 245 degrees C to 185 degrees C and similarly for BF-a monomer from 226 degrees C to 165 degrees C. The plausible mechanism of the benzoxazine ring opening reaction in presence of PPy is also discussed. Further, scanning electron microscopy (SEM) and X-ray diffraction studies suggest that the incorporation of PPy leads to the formation of fractal morphology. Consequently, the PPy inter-layered poly(C-f) and poly(BF-a) matrices contribute to the achievement of low value of dielectric constant (K = 3.39 and 3.83). In addition, PPy interlayer provokes enhanced thermal stability and higher LOI value. Thus, the present work demonstrates the catalytic role of PPy towards the curing reaction of benzoxazines and its contribution towards thermal and dielectric behaviour the of resulted matrices.