A highly efficient melamine/red phosphorus flame retardant for polyurethane‐based foams

Abstract

A highly dispersed melamine/red phosphorus (MA/RP) composite flame retardant was prepared by means of simple mechanical grinding. After co‐thermal pretreatment with polyether polyol (PPG‐2000) at 135°C, organic–inorganic hybrid foams (MA/RP/HF) containing MA/RP flame retardant were prepared by the one‐step method using main raw materials such as polyisocyanate and sodium silicate. When 0.5 wt% MA/RP with the mass ratio of 1:5 is added, MA can realize the uniform dispersion of RP in the substrate and enhance its flame retardancy, and the obtained MA/RP/HF presents uniform and closed pores and excellent basic properties. The TG results reveal that MA/RP/HF shows good thermal stability and the corresponding char residual rate reaches 37.9% at 800°C. The flame retardant test results prove that MA/RP/HF is capable of passing the V‐0 grade, with the LOI value being 26.8%. According to the cone calorimeter analysis, its peak heat release rate and total heat release decrease by 30.1% and 51.7% compared with those of rigid polyurethane‐based foam and by 40.1% and 30.0% compared with those of pure HF, respectively. Finally, the synergistic flame retardancy mechanism of MA and RP on polyurethane‐based foam was discussed.

Synergistic Flame Retardant Properties of Polyoxymethylene with Surface Modified Intumescent Flame Retardant and Calcium Carbonate

“…They are considered as the most promising flame retardant for POM, but the efficiency is not high enough, and the additional amount sometimes even exceeds the content of POM itself [ 19 ]. Lu et al made ME/RP composite flame retardant by simply mixing red phosphorus and melamine by mechanical grinding, which achieved excellent flame-retardant performance in polyurethane foam and had more advantages than using ME and RA alone [ 20 ]. Adding synergists is the easiest way to improve flame retardant efficiency by promoting the synergistic effect between the IFR components [ 21 ].…”

Preparation of flame retardant and thermal insulation polystyrene foams via high internal phase emulsion template

“…The limiting oxygen index (LOI) and UL‐94 vertical burning test are important indicators for evaluating the combustion performance of materials 40 . Table 3 lists the LOI values and vertical burning test results of pure polyHIPE and its composites with different amounts of APP/starch (or APP) added.…”

“…The limiting oxygen index (LOI) and UL-94 vertical burning test are important indicators for evaluating the combustion performance of materials. 40 When the APP content is increased to 15%, APP@polyHIPE achieves the UL-94 V-2 rating and its LOI value reaches 24.6%, exhibiting superior flame retardancy compared with PS foam prepared using traditional physical method. 41 It is worth noting that the addition of starch further improves the LOI values of the composites, reaching 25.8% at 15% of starch load, and APP/starch@polyHIPE fulfills the V-1 level of UL-94 test.…”

Surface Flame-Retardant Systems of Rigid Polyurethane Foams: An Overview

“…Among the additive types, halogenated flame retardants have been studied and used earlier, but they are being phased out due to adverse environmental effects. Research into improving the flame retardancy of RPUFs with aluminum hydroxide [ 5 , 6 , 7 ], expandable graphite (EG) [ 8 , 9 ], ammonium polyphosphate (APP) [ 10 , 11 , 12 ], and melamine (MEL) [ 13 , 14 , 15 ] is relatively mature. In addition, synthetic organic flame retardants containing phosphorus are rapidly developing due to their environmental friendliness, high flame-retardant efficiency, ease of modification, etc.…”