Novel Thermoset Nanocomposite Intumescent Coating Based on Hydroxyapatite Nanoplates for Fireproofing of Steel Structures

摘要

Thermoset nanocomposite intumescent coating swells under the influence of heat forming a thick cohesive insulating barrier; it is one of the most effective ways for fire protection of steel structures. This study reports on the sustainable fabrication of hydroxyapatite (HA) nanoplates as an efficient phosphorous-based flame retardant agent (phosphorous content of 18.5 wt%). Epoxy nanocomposite, based on the synergism between HA particles and advanced intumescent flame retardant agent (commercially known as AP750) was developed. This novel nanocomposite was able to resist a direct flame source at 1700 degrees C and to self extinguish; it demonstrated an enhanced flammability performance in cone calorimetry with 51% decrease in the peak heat released. Nanocomposite layer of 3 mm thickness was employed for steel substrate protection against direct heat source. The developed intumescent coating was able to protect the steel substrate from heat source at 900 degrees C. It offered an improved performance, in terms of the coating's mechanical barrier, and flame resistance properties. HA nanoplates could propose a gas phase effect due to the release of active flame scavengers such as PO2 center dotdocumentclass[12pt], PO center dot, and HPO center dot. Furthermore, HA could expose a condensed phase effect via the formation of a protective charr layer.