NON-REVERSIBLE TUNEABLE ELECTRICAL CONDUCTIVITY OF PANI-BASED CFRP IN THROUGH THICKNESS DIRECTION BY CONTROLLING DE-DOPING EFFECT OF POLYANILINE

In this work, Carbon Fabric Reinforced Plastics (CFRPs) with Polyaniline (PANI)-based matrix were prepared and their conductivity through thickness direction was controlled by controlling the inherent de-doping phenomenon of PANI. PANI was doped with a strong protonic acid, dodecylbenzenesulfonic acid (DBSA) and mixed with a cross-linking polymer, divinylbenzene (DVB). This mixture was further used to impregnate the carbon fabric layers to prepare conductive PANI-based CFRP (CF/PANI) composite. The de-doping phenomenon of PANI was capitalized to control the electrical conductivity of the CFRP through thickness direction. The property of PANI to get de-doped at higher temperature and longer annealing time was established with a series of experiments. Prepared CF/PANI was subjected to different annealing time to obtain the desired electrical conductivity. Electrical and mechanical properties of prepared CF/PANI were measured after each annealing time. Average electrical conductivity value > 1 S/cm in through thickness direction of CF/PANI was obtained. This conductivity could be reduced by thermal annealing. 3 CF/APNI samples were subjected to different annealing time to achieve 0.8, 0.5 and 0.3 S/cm electrical conductivity in through thickness direction. These 3 CF/PANI panels were tested against simulated thunder lightning strike with an intensity of 40 kA. The effect of electrical conductivity and mechanical properties of CF/PANI samples against lightning strike are demonstrated. UV-Vis analysis, FT-IR spectra and micro-images were used to demonstrate the de-doping phenomenon of PANI. Mechanical properties were measured after each thermal treatment cycle to determine any deteriorating effect on overall mechanical properties of the composites and finally the effectiveness of these panels against simulated thunder lightning test were tested.