Cu(Ⅱ) and Co(Ⅱ) complexes decorated ammonium polyphosphate as co-curing agents on improving fire safety and mechanical properties of epoxy-based building coatings

Abstract

Epoxy resin (EP) is widely used as an organic coating in the field of building materials (such as steel and timber). However, it’s high flammability and smoke release in fires further hinder its application in construction. Here, Cu(II) and Co(II) complexes decorated ammonium polyphosphates (BAPP@Cu and BAPP@Co) were synthesized by a facile strategy of chemical surface modification and used as multifunctional additives to enhance various properties of epoxy coatings. It has been found that both BAPP@Cu and BAPP@Co as co-curing agents not only promote the curing reaction of EP but also enhance the interfacial compatibility between the filler and the epoxy matrix. In addition, both BAPP@Cu and BAPP@Co endow EP with enhanced mechanical performance and heat insulation compared to pristine ammonium polyphosphate (APP). More importantly, both BAPP@Cu and BAPP@Co impart excellent fire safety to EP coatings. The peak heat release rate (pHRR) and peak CO production rate (pCO) of EP-6 %BAPP@Cu are decreased by 35.6% and 46.2%, respectively, compared to virgin EP. Similarly, EP-6 %BAPP@Co exhibits high fire performance, with a 57.7% reduction in pHRR and a 62.9% reduction in pCO, respectively, in comparison to virgin EP. This work reports a new strategy for the chemical modification of APP by metal complexes and provides a new perspective for the application of building coating materials.