Halogen-free flame-retardant rigid polyurethane foam with a nitrogen–phosphorus flame retardant

Abstract

A halogen-free flame retardant containing nitrogen and phosphorus, 2-[anilino-(6-oxobenzo[c][2,1]benzoxaphosphinin-6-yl)methyl]phenol (PDOP), has been synthesized by reaction of benzo[c][2,1]benzoxaphosphinine-6-oxide (DOPO) with 2-( N-phenyliminomethyl)phenol. Halogen-free flame-retardant rigid polyurethane foams (RPUF-PDOP) were prepared using PDOP as a flame retardant. The flammability was investigated using limiting oxygen index, a vertical burning test (UL-94), and a cone calorimeter. When PDOP (10 wt%) as flame retardant was added to RPUF (RPUF-PDOP10%), the limiting oxygen index value was increased from 18% to 27%, and a UL-94 V-0 rating was achieved; meanwhile, the peak heat release rate, total heat release, and the average mass-loss rates of RPUF-PDOP10% were reduced from 246 to 207 kW m−2, from 26.9 to 21.0 MJ/m2, and from 0.043 to 0.033 g/s, respectively. Especially, the initial decomposition temperature of RPUF-PDOP10% was decreased from 228°C to 209°C. The final residual char from decomposition of RPUF-PDOP10% was significantly increased up to 35.6%. The addition of PDOP did not markedly decrease the mechanical properties of the resulting flame-retardant RPUFs.

Flame retardation and thermal stability of novel phosphoramide/expandable graphite in rigid polyurethane foam

“…Additive‐type flame retardants become more common and low cost additives to endow RPUF good flame retardancy, such as 2‐[anilino‐(6‐oxobenzo[c] benzoxaphosphinin‐6‐yl)methyl]phenol(PDOP), melamine amino trimethylene phosphate (MATMP), DOPO‐BA, phosphorus‐melamine‐urea‐formaldehyde, ammonium polyphosphate (APP), dimethyl methyl phosphonate (DMMP), and hexaphenoxy‐cyclotriphosphazene (HPCP) . Besides of these substances, expandable graphite (EG) has been wildly used for flame retarding RPUF due to its low cost and excellent physical expansion action in condensed phase .…”

Novel Biobased Polyol Using Corn Oil for Highly Flame-Retardant Polyurethane Foams

“…Moreover, low density and ease in air permeability allow for a higher fire growth velocity [17]. In order to counter this issue, compounds such as additive and reactive flame retardants consisting of halogenated and non-halogenated compounds or, inorganic metal oxides, and hydroxides are added within the foam matrix during the synthesis [8,19,20]. Reactive flame retardants consist of compounds with functional groups that can readily get bonded within the foam matrix [6,8,9,21].…”

“…In practice, separate synthesis for such flame retardants could add to the cost of the final foams, while additive flame retardants consist of simple compounds and require very little concentrations to impart flame retardancy [7]. Although halogenated flame retardants are widely used, they suffer from several environmental issues [20,22,23]. Phosphorus-containing flame retardants serve as promising candidates to counter this issue.…”

Synergistic Flame Retardant Effects of Expandable Graphite and Ammonium Polyphosphate in Water-Blow Polyurethane Foam

“…Because of the problems related to the large amount of toxic and corrosive gases and smoke released during PU decomposition, halogen-free flame retardants have been facilitated rapidly. Over the past decades, halogen-free flame retardants have been increasingly applied in polymeric systems [17,18]. e phosphorus-nitrogen intumescent flame retardants (IFR) are widely used as halogen-free additives because they provide excellent fire protection with less smoke and lower toxicity [19][20][21][22].…”