Effect of Carbon Nanoparticles on Properties of Polyetherimide Fibers

In the present work, fibers based on heat-resistant amorphous polyimide brand Ultem-1000 were prepared by melt extrusion. Vapor-grown carbon nanofibers (VGCFs) and single-wall carbon nanotubes (SWCNTs) were used to increase the mechanical characteristics of the polymer fibers. The fibers were characterized by scanning electron microscopy (SEM), thermophysical and mechanical tensile analysis. SEM study revealed very good distribution of the carbon nanofillers throughout the polyimide fiber volume. The mechanical testing of the unoriented nanocomposite fibers showed that the introduction of VGCFs or SWCNTs led to an increase in tensile strength and modulus. High-temperature drawing allows obtaining polyimide nanocomposite fibers with significantly increased mechanical properties (»300 MPa for strength and »4.6 GPa for modulus).

Decomposition and Flammability of Polyimide Graphene Composites

Polyimide-graphene composites were synthesized by in-situ condensation polymerization and the thermal stability and decomposition behavior of the composites were studied. Polyimides, because of their aromatic backbone, are a class of fire-retardant polymers. Their high char retention ≥50% at testing temperatures ≥600 °C makes them thermally stable polymers. The effect of nanographene sheets on the decomposition behavior of polyimide is presented in this paper. It is shown that the reinforcement of polyimide with nanographene sheets significantly decreased the rate of decomposition of polyimide and increased the char retention of the composite. Thermogravimetric analysis data were used to assess the thermal stability, rate of mass loss and predicted limiting oxygen index of the neat polyimide and composites. Results obtained showed around a 43% decrease in the rate of polyimide degradation at 50 wt.% graphene loading. The limiting oxygen index of the polyimide nanocomposite was calculated by using the char retention, and it was found to increase by up to 24% at 50 wt.% graphene loading over that for the neat matrix.

Photoluminescence, thermal and surface properties of triarylimidazole-containing polyimide nanocomposite films

Three series of triarylimidazole-containing polyimide nanocomposite films were prepared via thermal imidization. Due to the introduction of inorganic nanoparticles including SiO2, Al2O3 and Si3N4, the fluorescence intensities of these composite films were clearly increased.