Effect of layered double hydroxide, expanded graphite and ammonium polyphosphate additives on thermal stability and fire performance of polyisocyanurate insulation foam

Abstract

This work examines the effect of Layered Double Hydroxides (LDHs), Expandable Graphite (EG) and Ammonium Polyphosphate (APP) on the thermal stability and behaviour under fire conditions of polyisocyanurate (PIR) insulation foams. Virgin materials' and char residues' morphologies were analyzed with a variety of experimental techniques including field emission scanning electron and optical microscopy along with Raman spectroscopy. Thermal stability and burning behaviour were examined using thermogravimetric (TGA) coupled with Fourier Transform Infrared (FTIR) spectrometer and cone calorimeter. TGA results suggested a decrease in degradation temperature upon introduction of fillers in PIR samples. FTIR spectra were used to determine the absorbance intensity of the different pyrolysis gases. Cone calorimeter data analysis established a limited effect on reducing the rate of heat release rate and smoke production with the inclusion of LDHs. However, EG or EG + APP addition, caused a considerable decrease in heat release rate, owing to the increased char strength and the release of non-combustible gases. The positive effect of EG or EG + APP in the fire behaviour of PIR foams was further supported by the morphological evaluation of their residual char samples.

A Systematic Review and Bibliometric Analysis of Flame-Retardant Rigid Polyurethane Foam from 1963 to 2021

“…However, the addition of large amounts of expanded graphite to RPUF can lead to the deterioration of its mechanical properties. Synergistic flame-retardant or surface-modification methods can reduce the damage to mechanical properties of RPUF by expanded graphite [ 58 ]. This situation is also prevalent for other mechanically added flame retardants.…”

Properties of flame-retardant leaf fiber cement-based composites at high temperatures

“…As shown in Figure 5 , APP has an antisymmetric stretching vibration peak of NH4+ at 3431 cm-1, N–H stretching vibration peak of ammonium polyphosphate at 3242 cm-1, and N–H bending vibration peak at 1668 cm-1, P=O stretching vibration peak at 1290 cm-1. 1115cm-1 is the asymmetric stretching peak of the P–O bond, and 916cm-1 is the symmetric stretching peak of the P–O bond of ammonium polyphosphate [ 20 , 21 ]. The stretching vibration peak of Mg–OH is denoted as MH.…”

Effects of Various Types of Expandable Graphite and Blackcurrant Pomace on the Properties of Viscoelastic Polyurethane Foams

“…Therefore, in recent years, researchers have focused on finding synergistic effect of expandable graphite (EG) with other additive flame retardants [ 40 , 41 , 42 ] or nanofillers [ 43 , 44 , 45 ]. The main mechanism to improve the flame resistance is to increase the char yield [ 46 , 47 , 48 ].…”