Electrically conductive adhesive based on novolac-grafted polyaniline: synthesis and characterization

The aim of this study was to design and development of an efficient and facile strategy for the grafting of polyaniline (PANI) onto novolac-type phenolic resin. For this purpose, novolac resin (NR) was functionalized using p-antranilic acid in the presence of p-toluene sulfonic acid (p-TSA) as the dehydrating agent to afford phenylamine-functionalized novolac resin macromonomer (PhANRM). The graft polymerization of aniline monomer onto the PhANRM macromonomer was initiated by oxidized phenylamine groups after addition of ammonium peroxydisulfate (APS), and p-TSA-doped PANI was grown on NR via an oxidation polymerization method. The chemical structures of all samples were characterized using Fourier transform infrared (FTIR) and proton nuclear magnetic resonance (¹H NMR) spectroscopies. The electrical conductivity as well as electroactivity of the synthesized NR-g-PANI were investigated and compared with corresponding properties of pure PANI. The mechanical and adhesive features of the fabricated samples were also examined in the terms of tensile and lap shear strengths as well as elongation at break. As the results, the synthesized NR-g-PANI may be applied as electrically conductive adhesive, coating material, electromagnetic interference (EMI) shielding or other industrial fields mainly due to high mechanical and low cost advantages of NR as well as high thermal stability of the both NR and PANI.