Preparation and properties of polyimide-based nanocomposites containing functionalized Fe3O4 nanoparticles

Polyimide (PI)/Fe 3 O 4 nanocomposites were successfully prepared via the thermal curing of different amounts of Fe 3 O 4 nanoparticles (2, 4, 6 and 8 wt%) functionalized by 3-aminopropyltriethoxy silane as a coupling agent, containing the poly(amic acid) derived from 5-diamino- N-(4-(4,5-diphenyl-1H-imidazol)phenyl)benzamide and 3,3′,4,4′-benzophenonetetracarboxylic dianhydride. The effect of Fe 3 O 4 nanoparticles on the structural, thermal and magnetic properties of nanocomposites was investigated. The Fourier transform infrared spectroscopy and scanning electron microscopy (SEM) results reveal that the surface of Fe 3 O 4 nanoparticles is sufficiently compatible with PI through linkage of the coupling agent between Fe 3 O 4 and the polymer. Also, the SEM image shows that Fe 3 O 4 nanoparticles are dispersed uniformly in the polymer matrix, with a particle size of around 78 nm. The nanocomposites of 2 and 8 wt% exhibit the saturation magnetization values of 0.055 and 0.170 emu g − 1 , respectively. The thermogravimetric analysis data show that the thermal stability of the nanocomposites is improved as compared to the pure PI.