(374e) Reinforced Magnetic Epoxy Nanocomposites with Conductive Polypyrrole Nanocoating on Nanomagnetite As a Coupling Agent

The new function of polypyrrole (PPy) to serve as a coupling agent has been demonstrated in preparing conductive epoxy resin nanocomposites with PPy coating on magnetite (f-Fe₃O₄) nanoparticles. Compared with pure epoxy suspension, the viscosity of epoxy nanosuspensions with 5.0 and 10.0 wt% f-Fe₃O₄ nanoparticles was almost the same. The glass transition temperature (T_g) of cured solid epoxy polymer nanocomposites (PNCs) with 30.0 wt% f-Fe₃O₄ nanoparticles was 22.3 ^oC higher than that of cured pure epoxy (88.2 ^oC) in the dynamic mechanical analysis (DMA).¹ At 50 wt% weight loss, the decomposition temperature of the cured epoxy PNCs with 30.0 wt% f-Fe₃O₄ nanoparticle was delayed from 421.5 (cured pure epoxy) to 483.4 ^oC. Compared with the tensile strength of 83.0 MPa for the cured pure epoxy,² the enhanced tensile strength of 91.7 MPa observed in the cured epoxy PNCs with 5.0 wt% f-Fe₃O₄ nanoparticles is attributed to the introduced interfacial interaction between the nanoparticles and the host epoxy matrix, through the PPy nanocoating, as observed in the fracture surface. The volume resistivity of the cured epoxy PNCs with 30.0 wt% f-Fe₃O₄ nanoparticles decreased almost 7 orders of magnitude compared with the cured pure epoxy (1.6×10¹³ µΩ cm). The cured epoxy PNCs exhibited good magnetic properties; the surface functionality and epoxy polymer had little effect on the magnetic moment of the Fe₃O₄ nanoparticles. The cured epoxy PNCs with f-Fe₃O₄nanoparticles showed positive permittivity, and the permittivity increased with increasing particle loading. The role of PPy nanocoating on the nanocomposite formation mechanism was investigated by using the FT-IR and TGA tests.

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(2)        Gu, H.; Tadakamalla, S.; Zhang, X.; Huang, Y.; Jiang, Y.; Colorado, H. A.; Luo, Z.; Wei, S.; Guo, Z.: Epoxy resin nanosuspensions and reinforced nanocomposites from polyaniline stabilized multi-walled carbon nanotubes. Journal of Materials Chemistry C 2013, 1, 729-743.