Citation

Li T, Yu R, Zhao D. ACS Omega 2021; 6(23): 15246-15256.

Copyright

(Copyright © 2021, American Chemical Society)

DOI

10.1021/acsomega.1c01524

PMID

34151103

Abstract

A novel halogen- and phosphorus-free intrinsic flame-retardant foam is fabricated from curable phenol-terminated polyphenylene ether resin with a high molecular weight using phenol, formaldehyde, and diphenyl ether as starting materials. The limiting oxygen index (LOI) of the pure foam is 24.90% ± 0.28. When 0.5 wt % silica sol is added, the LOI of the foam (SPF-0.5) is up to 28.5% ± 0.15 and both the combustion heat release rate and total combustion heat are low. Moreover, the SPF-0.5 foam exhibits high carbon residue, high compressive strength, and low pulverization rate and is superior to some previously reported phenolic foam. The flame-retardant mechanism includes the condensed-phase flame retardation and the gas-phase flame retardation, with the former being the main step, which is based on the high cross-linking density, the higher strength and smaller size of foam cells, and the formation of a carbon-silicon compound in the foam. This halogen- and phosphorous-free flame-retardant foam is also environmentally benign.

Language: en