A green organic-inorganic PAbz@ZIF hybrid towards efficient flame-retardant and smoke-suppressive epoxy coatings with enhanced mechanical properties

Developing sustainable bio-based flame retardants for flammable polymers has been a research trend. However, applying bio-based flame retardants to confer excellent flame retardancy, smoke suppression, and mechanical properties to polymers remains a formidable challenge. Herein, a green organic-inorganic hybrid (PAbz@ZIF) was readily prepared through a simple neutralization reaction and in-situ generation method and applied to fabricate high-performance flame-retardant epoxy coatings (EP-PAbz@ZIF). It has been shown that PAbz@ZIF hybrids can enhance the curing activity of epoxy coatings in addition to their excellent dispersibility and interfacial compatibility. In addition, the epoxy coating containing 5.0 wt% PAbz@ZIF (EP-5%PAbz@ZIF) exhibits a higher char yield (from 25.1 wt% to 31.5 wt%) in comparison to pristine epoxy resin (EP). More importantly, the PAbz@ZIF-based epoxy coatings show more efficient flame retardancy and smoke suppression compared to pristine EP. For instance, the 5.0 wt% PAbz@ZIF enables EP-5%PAbz@ZIF to obtain a satisfactory UL-94 rating of V0. Meanwhile, the peak heat release rate, total smoke production, peak CO production rate, and peak CO2 production rate of EP-5%PAbz@ZIF are remarkably decreased by 48.6%, 20.5%, 38.6%, and 56.7%, respectively. Furthermore, EP-5%PAbz@ZIF exhibits enhanced heat insulation performance, flexural strength, and impact strength. This work offers a feasible idea for designing green organic-inorganic PAbz@ZIF hybrids and fabricating high-performance flame-retardant epoxy coatings.