Bis-amino functionalized iron N-heterocyclic carbene as epoxy resins hardener and flame behaviour modifier

Evaluation of Novel Bio-Based Amino Curing Agent Systems for Epoxy Resins: Effect of Tryptophan and Guanine

“…A similar concept can be applied to the present hardener coadjutants, thus assuming that imidazole NH are expected to react faster than primary and aromatic amines. Additionally, it is worth pointing out that all the selected molecules ( Figure 1A-D) display a significant nitrogen atomic fraction, which, as previously reported [7,29], seems to be an effective way of improving epoxy resin flame retardancy.…”

Synthesis of functionalized iron N-heterocyclic carbene complexes and their potential application as flame behavior modifier in cross linked epoxy resins

“…It is also worth to point out that the char content of EC157/3 systems at 600°C is similar to that one of EC157/2 formulations with the same hardener content. 55 Anyway, considering the higher molecular weight of 3 with respect of 2, EC157/3 formulations results in an iron content lower than EC157/2 systems, as shown in Table 1 (See Experimental Section). Hence, the presence of aromatic moieties seems to promote the charring ability of the systems which, in turn, should result in better flame retardancy.…”

“…An analogous assessment carried out in the presence of 5, 7.5 and 10% of 2 was able to positively cross-link DGEBA though reaching slightly lower Tg (104°C, 105°C and 110°C respectively). 55 TGA curves (Figure 2) show, in addition to a high thermal stability of the resins with respect to the plain unreacted epoxy precursor, a significant char production in inert atmosphere (in the range of 20-30% of the initial weight), that cannot be attributed to the DGEBA degradation pattern neither solely to the iron-related non-volatile residue. Such a behavior can be instead ascribed to the presence of the iron-based hardener which, as reported in literature [12][13][14] can catalyze the char formation.…”