Citation

Zhang X, He Q, Gu H, Colorado HA, Wei S, Guo Z. ACS Appl. Mater. Interfaces 2013; 5(3): 898-910.

Copyright

(Copyright © 2013, American Chemical Society)

DOI

10.1021/am302563w

PMID

23273023

Abstract

Both fibril and spherical polyaniline (PANI) nanostructures have successfully served as nanofillers for obtaining epoxy resin polymer nanocomposites (PNCs). The effects of nanofiller morphology and loading level on the mechanical properties, rheological behaviors, thermal stability, flame retardancy, electrical conductivity and dielectric properties were systematically studied. The introduction of the PANI nanofillers was found to reduce the heat release rate and increase the char residue of epoxy resin. A reduced viscosity was observed in both kinds of PANI - epoxy resin liquid suspension samples at lower loading (1 wt% for PANI nanospheres; 1 and 3 wt% for PANI nanofibers), the viscosity was increased with further increasing the PANI loading for both morphologies. The dynamic storage and loss modulii were studied together with glass transition temperature (Tg) being obtained from the peak of tan (sic). The critical PANI nanofiller loading for the modulus and Tg was different for the nanofibers (1 wt%) and for the nanospheres (5 wt%). The percolation thresholds of the PANI nanostructures were identified with the study of dynamic mechanical property and electrical conductivity, and due to the higher aspect ratio, nanofibers reached the percolation threshold with a lower loading (3 wt%) than the PANI nanospheres (5 wt%). The PANI nanofillers could increase the electrical conductivity of matrix, and at the same loading, epoxy nanocomposites with the PANI nanofibers showed lower volume resistivity than epoxy with nanospheres, which is discussed with the contact resistance and percolation threshold. The tensile test indicated an improved strength of epoxy matrix with the introduction of the PANI nanospheres at lower loading (1 wt%). And compared with pure epoxy, the elasticity modulus was increased for all the PNC samples; and further study on the fracture surface revealed an enhanced toughness. Finally, the real permittivity increased with increasing the PANI nanofiller loading, and the enhanced permittivity is analyzed with interfacial polarization.

Language: en