Rheological testing of a curing process controlled by Joule heating

A multi-walled carbon nanotubes (MWCNT)/epoxy system was cured through direct application of a DC electric field while rheological properties were measured. Therefore, rheological testing was performed simultaneously to the curing reaction. Each plate was electrically connected to either pole of a DC power supply so that, by means of the Joule effect, heating was controlled by application of an electric potential. The plates were also connected to the poles of an LCR meter in order to perform dielectric analysis to evaluate the initial conductivity of the sample. The temperature of the sample was measured by a thermographic camera connected to a PID control unit used for adjusting the electric potential according to the heating program. It was observed that wt 3% of MWCNTs and 1 A current allowed reaching 200 °C, a sufficiently high temperature to fully cure most thermoset systems.