Reactive flame retardant with core‐shell structure and its flame retardancy in rigid polyurethane foam

Abstract

With a shell of poly (methyl methacrylate-co-hydroxyl ethyl acrylate) (PMMA-HA), microencapsulated ammonium polyphosphate (MHAPP) is prepared by in situ polymerization. The core-shell structure of the reactive flame retardant (FR) is characterized by Fourier transform infrared (FTIR) and scanning electron microscopy/energy dispersive spectroscopy (SEM/EDS). The results of water leaching rate and water contact angle measurements show that ammonium polyphosphate (APP) is well coated by a hydrophobic shell. Due to the presence of active groups (-OH) and hydrophobic groups (-CH 3 ) in shell, MHAPP exhibits better compatibility, flame retardancy, and water resistance compared with neat ammonium polyphosphate (APP) in rigid polyurethane foam (PU). Compression strength of PU/MHAPP with suitable loading is higher than that of PU/APP and PU, the reason is that the active groups in shell can improve the compatibility of MHAPP in PU composite. From thermal stability and residue analysis, it can be seen that the presence of reactive flame retardant shows positive effect on thermal stability of PU composite at high temperature, results also indicate that MHAPP can promote the carbonization formation efficiency of PU composite during combustion process compared with APP.

The Effect of Soluble Ammonium Polyphosphate on the Properties of Water Blown Semirigid Polyurethane Foams

“…Ammonium polyphosphate (APP), as inorganic phosphorus flame retardant with nitrogen-phosphorus synergistic intumescent effect [17][18][19][20], has the advantages of thermal stability and lasting effect. APP can also improve the mechanical properties of the material, so it is often used with other flame retardants [21][22][23], and the most common APP flame retardant studied by researchers is form II, of which the polymerization degree is greater than 1000 [24][25][26][27]. In this paper, the water blown SPUF is synthesized only with soluble ammonium polyphosphate (SAPP) with a low polymerization degree.…”

Graphene and poly(ionic liquid) modified polyurethane sponges with enhanced flame‐retardant properties

“…When 1.5% Gr was added, the maximum LOI for the PU–PIL–Gr sample was measured to be as high as 26.1%. With such an LOI value, the PU–PIL–Gr samples were able to compete with reported PU materials . Clearly, the introduction of PIL and Gr into the sponge framework efficiently enhanced the LOI of the resulting modified sponges.…”

Continuous flame-retardant actions of two phosphate esters with expandable graphite in rigid polyurethane foams

“…Due to the less health hazard, the flame retardants containing phosphorus/nitrogen applied in RPUF have received more attentions. According to the previous literature, some researchers used a lot of additiontype flame retardants, such as phosphaphenanthrenephosphonamidates(EDAB-DOPO) [14], ammonium polyphosphate (APP) [15,16], polydopamine (PDA) [17], expandable graphite (EG) [18e20], polyhedral oligomeric silsesquioxane (POSS) [21], triphenylphosphate (TPP) [22], dimethyl methylphosphonate (DMMP) [23e25], dimethylpropanphosphonate (DMPP) [26], hexaphenoxy-cyclotriphosphazene (HPCP) [27] and aluminium phosphinate [28]. They all can enhance the flame retardancy of RPUFs.…”