Flame retardancy working mechanism of methyl‐DOPO and MPPP in flexible polyurethane foam

Abstract

The chemical nature of flexible polyurethane (flex PU) foams, the low density, the high air permeability and the open cell structure cause this material to be highly flammable. The new phosphorus flame-retardant (FR) methyl-DOPO (9, 10-dihydro-9-oxa-methylphosphaphenanthrene-10-oxide) is known to show an excellent flame retarding behavior in flex PU foam by acting mainly in the gas phase. In this study, the FR working mechanism of methyl-DOPO and its ring-opened analogue MPPP (methylphenoxyphenyl-phosphinate) is investigated by TGA, TG-MS, FMVSS 302 and Cone Calorimeter measurements. Under TG-MS conditions comparable concentrations of low molecular weight species such as HPO, mathrmCH 3PO or PO 2 are released. These species are able to scavenge the H- and OH-radicals in the radical chain reactions of the flame leading to a significant increase in the CO/CO 2 ratio and the smoke density during cone calorimeter experiments. Finally, the flame retardancy of MPPP is determined to be less efficient in flex PU foam because of the higher vapor pressure compared with methyl-DOPO. Here, the vaporization of methyl-DOPO occurs in the same temperature region as the depolymerization of the urethane and the bisubstituted urea groups during pyrolysis of the foam leading to an optimal interaction

Inherently Flame-Retardant Flexible Polyurethane Foam with Low Content of Phosphorus-Containing Cross-Linking Agent

“…A heat flux of 25 kW/m 2 is ordinarily chosen for flexible polyurethane foam, as the foam cannot withstand high heat flux because of its open-cell structure. 2,3,8,11,12 Moreover, to make our results comparable with those of others, in this investigation, the same heat flux was also applied. Figure 4 shows the HRR and THR curves of neat FPUF, FPUF-CPOP, and FPUF-PTMAs.…”

An Overview of Mode of Action and Analytical Methods for Evaluation of Gas Phase Activities of Flame Retardants

“…To understand the activity of phosphorus derivatives on flexible polyurethane (PU) foams, combustion and the thermal behavior of foams containing phosphorus derivatives were examined [18]. TGA-MS measurements were performed for methyl-DOPO (9,10-dihydro-9-oxa-methylphosphaphenanthrene-10-oxide) and MPPP (methylphenoxyphenyl-phosphinate) containing foams.…”

“…It is very difficult to monitor and identify the decomposition pathways of flame-retardants in gas phase. Some methods have recently been developed in order to analyze and quantify the decomposition products of a flame retardant in a polymeric matrix [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19]. With emerging analytical techniques, it has become possible to get a better understanding of the mode of action of flame-retardants.…”

Effect of Meltable Triazine-DOPO Additive on Rheological, Mechanical, and Flammability Properties of PA6

“…Concerning the phosphorous-containing flame retardants, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) and its derivatives could be an attractive FR solution for PA6 due to their relatively higher thermal stability [25][26][27][28]. DOPO and its derivatives are known to predominantly act by a gas-phase mechanism, through the formation of PO¨radicals, which might also be assisted by a condensed-phase activity via the incorporation of specific functionalities at the DOPO moiety [25,29]. Despite the promising performance of these non-halogenated FRs, there are still some problems which need to be overcome.…”