Thermomechanical characterization of Nano-Fe₃O₄ reinforced thermoplastic adhesives and single lap-joints

In this work, Acrylonitrile Butadiene Styrene (ABS) was selected as the thermoplastic adhesive and reinforced with varying concentration of ferromagnetic nanoparticles (FMNP) through melt processing. The effect of FMNP content on thermo-mechanical properties was experimentally characterized. Also, lap-joints using glass-fiber substrates were bonded using ABS/FMNP films through conventional oven-bonding and induction-bonding techniques, and their effect on resulting joint behavior was studied. Further, effects of adhesive melt-processing mix-times and O₂-plasma surface treatment on resulting joints were also studied. Results indicate that the percolation limit of FMNP to ensure melting and flow during induction bonding was 8 wt%, and the flow time decreased with increase in FMNP content. ABS adhesive with 16 wt % FMNP showed good balance of stiffness and strength relative to other concentrations. Both oven and induction bonded joints that were O₂ - plasma treated had higher ductility relative to untreated joints. Further, induction bonded joints with both O₂ -plasma and substrate preheating had 15% higher peak loads relative to oven-bonded joints. Optimization of the induction heating process parameters along with surface functionalization of particles and substrates is essential to fully exploit the benefits offered by these novel thermoplastic adhesives.