Hardener type as critical parameter for the electrical properties of epoxy resin/polyaniline blends

Epoxy resin/polyaniline-salt (EP/PANI-DBSA) blends were prepared and cured with different types of hardeners. The effect of hardener type on the volume resistivity of the blends was investigated. It was found out that acidic curing agents support the conductive character of polyaniline, while alkaline hardeners conflict this property. Moreover, colour changes of the mixtures after the addition of the hardener revealed possible transformation of the conductive PANI-DBSA salt to the nonconductive PANI base form. An UV-vis analysis confirmed these assumptions. Despite of the acidic character of the anhydride type hardener, low conductivity was obtained. This was related to its insufficient curing action in the presence of PANI-DBSA. Furthermore, IR spectra of EP/PANI-DBSA blends varying the hardener type and the wt% of PANI-salt (<10 wt%) were recorded. These indicate a possible connection of the shoulder creation at the 1585 cm(-1) band, spectral region 1575 to 1560 cm(-1), with the degree of volume resistivity. (C) 2005 Springer Science + Business Media, Inc.