Thermal, combustion and optical properties of new polyimide/ODA-functionalized Fe3O4 nanocomposites containing xanthene and amide groups

Abstract

A new soluble polyimide was successfully synthesized via direct poly-condensation reaction between aromatic diamine containing xanthene group and aliphatic dianhydride. Multifunctional polyimide including xanthene derivatives, amide groups and high content of aromatic rings as well as aliphatic linkages was designed and synthesized. The polyimide was characterized by size exclusion chromatography, Fourier transform infrared spectroscopy and nuclear magnetic resonance (1H NMR). Fe3O4 nanoparticles were functionalized by 4,4′-oxydianiline (ODA). Polyimide/Fe3O4 nanocomposites were prepared by covalently embedding the ODA-functionalized Fe3O4 (ODA-Fe3O4) containing amine groups (5 and 8 mass% of the nanoparticle). This functionality not only gave specific characteristics to Fe3O4 nanoparticles but also improved the interphase interaction between the nanoparticles and the polyimide matrix through covalent attachment. For comparison, nanocomposites using unmodified Fe3O4 nanoparticles also were prepared. The TEM analysis showed better dispersion of ODA-Fe3O4 within the polyimide matrix, which arising from formation of covalent bonding between ODA-functionalized Fe3O4 and the polyimide chains. Moreover, magnetic, optical, combustion and thermal properties of the polyimide and the corresponding nanocomposites were studied. Thermo gravimetric analysis results indicated improving on thermal properties of the polyimide nanocomposites as compared with the neat polyimide. According to microscale combustion calorimetry (MCC) analysis, 73.5% reduction in the peak heat release rate value was achieved by introducing 8 mass% of ODA-Fe3O4 in the polyimide matrix. Moreover, MCC analysis showed that ODA-Fe3O4 have better efficiency on improving the flame retardancy of the polyimide as compare with unmodified Fe3O4 nanoparticles.