Study of epoxy resin curing process by applying internal friction technique

Curing process of an amine-epoxy system was investigated using vibrating reed technique and torsion pendulum apparatus, working at frequencies of about 100 Hz and 1 Hz, respectively. The measurements of mechanical spectra were carried out in isothermal conditions (300–325 K) at different frequencies in time domain i.e. in the course of chemical reaction between epoxy resin and a hardener. It was shown that the curing reaction is observed as an asymmetrical maximum of Q−1(t) which position is correlated with the inflection point of free vibrations frequency f(t) curve. An increase of the measurement temperature and frequency causes a shift of the observed mechanical spectra into shorter times.