Figure 6: Rheology and dielectric relaxometry characterization of the curing performance of the homopolymerized epoxy ink system as a function of catalyst loading and temperature.

Top panel: Room parallel plate oscillatory strain rheology measurements of the BPF resin on which we base our ink, at catalyst loadings of 0.1–2 wt% (conducted at room temperature. Note that at high catalyst loadings, the effective work time of the resin is ~75 hours and at low loadings (0.1 wt%) the room temperature work time is >350 hours. Lower panel: dielectric relaxometry analysis of the effective network curing process in the based BPF resin, at a catalyst loading of 0.1 Wt%. Despite being stable for over 250 hours at this low loading, these data show that a primary ‘green strength cure’ may be attained in only 5 hours at 80 °C, with full conversion of ~24 hours. At higher temperatures (150–200 °C) thermal snap curing may be achieved in under a minute. Such rapid curing is difficult to assess using relaxometry, but may be observed qualitatively in Video S2.