Nano-ZnO modified geopolymer composite coatings for flame-retarding plywood

作者：Wang, YaChao^*; Xu, Mingrui; Zhao, JiangPing; Xin, A.

来源：CONSTRUCTION AND BUILDING MATERIALS, 2022, 338: 127649.

DOI：10.1016/j.conbuildmat.2022.127649

• Flame retardants
• Nano-ZnO
• Pyrolysis kinetics
• Silica fume
• Formaldehyde

Herein the nano-ZnO/melamine polyphosphate (MPP) co-doped silica fume-based geopolymer composite coatings is fabricated for flame-retarding plywood. Its flame-retarding mechanism is investigated by microstructural characterizations and pyrolysis kinetics. The results show that an appropriate dosage of nano-ZnO (0.47 wt%) enhances flame retardancy, evidenced by the fire performance index increased to 2.98 s center dot m(2)center dot kW(-1) from 1.10, the fire growth index (FGI) decreased from 0.48 to 0.23 kW center dot m(- 2)center dot s(- 1), the flame retardant index (FRI) climbs from 1 to 2.79. Because the doped ZnO initiates the formation of ceramic-like Si/C/P residues, the as-formed ZnP4O11 is determined through the reactions between MPP and nano-ZnO. The ceramic-like reactions make the pyrolysis E alpha rise from 204.30 to 255.61 kJ center dot mol(-1) at 800 similar to 1000 ?C, according to the as-identified three-stage deceleration F3) of pyrolysis kinetics, resulting in the resilient and interpenetrating residues with a formaldehyde adsorption rate of 56%. It seeks effective recycling of metallurgical solid waste for preparing ecological flame retarding coatings, proposing an efficient approach for quantitatively probing the Si/C/P residues.