Study of cure of epoxy resins by torsional braid analysis

Abstract

The use of torsional braid analysis (TBA) for the dynamic mechanical characterisation of polymers in composites has been inhibited to some degree by difficulties associated with both the measurement and processing of data. Methods for overcoming difficulties associated with spurious motions of the TBA pendulum and for the rapid and optimum processing of raw output data are outlined. A description follows of the application of the modified TBA technique to the analysis of six nominally similar epoxy resins systems. It is shown, by the presentation of comparative data, that the TBA method gives highly reproducible results, with little scatter, in studies both of gelation and vitrification times over a wide range of isothermal temperatures, and of activation energies for the processes involved, and also in studies of dynamic mechanical behaviour over a wide temperature range.