Investigation of Aluminate Coupling Agent as Modifier and Its Application on Improving Flame Retardant of Intumescent Flame Retardant Coatings

Intumescent flame retardant coating modified by aluminate coupling agent were prepared via sol-gel method using ammonium polyphosphate, Polyacrylamide, aluminate coupling agent (ACA), and boron nitride (BN). The effect of modification of ACA on its flame retardant and characterization were preliminarily studied by cone calorimeter, scanning electron microscope, surface tensiometer and contact angle measurement. It is found that the addition of ACA can increase the expansion rate of carbon layer, and a stronger blocking effect can lead to a better property of flame retardant. The sample containing BN, after being modified by 3M NaOH and ACA, dramatically decreases heat release rate, especially reduce the peak heat release rate (pHRR) by 54% and total heat release by 16%, respectively. Moreover, the time to ignition was delayed by 175%. Through examining the residues and pyrolysis products of the coating samples, the mechanism of enhanced flame retardant that promotes the char-forming and heat barrier of the modification of ACA and BN is proposed. This work can offer a significant guide for further studying of ACA and modified BN on the flame retardant.