Thermo-mechanical properties and structural features of diglycidyl ether of BIS phenol a cationically cured by electron beam radiation

The thermo-mechanical properties and structural features of diglycidyl ether of bisphenol A cationically cured by electron beam radiation have been studied by FT-NIR spectroscopy, dynamic mechanical analysis (DMA), MTDSC and AFM. The influence of formulation (onium salt nature and content, presence of additives) and of EB-treatment parameters (doses, thermal treatment) on the glass transition temperature (Tg) have been investigated. The conditions for achieving a high level of conversion together with the control of the final Tg values were determined. The presence of several relaxation peaks observed by DSC and DMA analysis suggests the presence of heterogeneities in the formed network. AFM analyses reveal the presence of nanoclusters interpreted as local variations of cross-link densities in the formed network.

► The nature of onium salt exerts a strong influence on reactivity. ► AFM reveals the presence of nanoclusters. ► Local variation of cross-link densities is correlated with DMA data. ► Tg of the network can be controlled and modulated by formulation with additives.