Novel design of MOFs-based hierarchical nanoarchitecture: Towards reducing fire hazards of epoxy resin

Abstract

The inherent inflammability of epoxy resin (EP) has seriously limited its further application. The structural design of flame retardants has huge potential for boosting the fire safety properties of polymer materials. Herein, a novel MOFs-based hierarchical nanoarchitecture (ZIF-8@PA@SiO2) was constructed, composed of ZIF-8 nanoparticles, as well as in-situ grown phytic acid (PA) and silica. The results indicated that not only was ZIF-8@PA@SiO2 uniformly dispersed in the EP matrix, but it also formed a good interface bond, which was beneficial to boosting the thermal and fire safety properties of EP composites. The incorporation of ZIF-8@PA@SiO2 markedly decreased the maximum weight loss rate (MLRmax) and increased char residues. Compared with neat EP, the limiting oxygen index (LOI) value of EP/5% ZIF-8@PA@SiO2 increased from 23.4% to 28.8%. Furthermore, the peak heat release rate (PHRR), fire growth index (FGI), peak smoke production rate (PSPR), peak CO production rate (PCOPR) and smoke factor (SF) were decreased by 38.3%, 41.6%, 45.5%, 42.9% and 69.3%, respectively. The TG-FTIR results provided strong evidence for suppressed emissions of CO, aromatic, hydrocarbons and carbonyl, further corroborating the impeded heat release and the hindered fire toxicity, which were primarily ascribed to the barrier effect, free-radical scavenging and dilution effect of the multi-integrated P/N/Si-containing MOFs-based hierarchical nanoarchitecture.