Properties of a novel inherently flame‐retardant rigid polyurethane foam composite bearing imide and oxazolidinone

Abstract

A novel inherently flame-retardant rigid polyurethane (PU) foam with imide and oxazolidinone was prepared by using 3,3 0 ,4,4 0biphenyltetracarboxylic dianhydride (PTDA) and 9,10-dihydro-9-oxa-(10-glycidoxypropylene)-10-phosphap-henanthrene-10-oxide (e-DOPO) as reactive flame retardants. The physical and mechanical properties of the prepared PU foams were investigated. The compressive strength was improved to 0.22 MPa, the thermal conductivity decreased, and the density hardly changed. Thermogravimetric (TG) analysis and TG analysis coupled with Fourier transform infrared spectroscopy indicated that the PTDA and e-DOPO showed a small improvement in thermal properties. The fire behaviors were evaluated based on the limited oxygen index (LOI), cone-calorimetry experiment, and smoke-density test. The LOI of the PU foam with PTDA and e-DOPO reached 22.4%. The peak of heat release rate and total heat release decreased to 227.50 kW m −2 and 11.27 MJ m −2 from 281.28 kW m −2 and 14.05 MJ m −2 , respectively. The morphologies of the PU foam and residues after the cone-calorimetry test were characterized by scanning electron microscopy. X-ray photoelectron spectroscopy analysis indicated that PTDA and e-DOPO lead to an increase in graphite in the residue and the formation of a better barrier to prevent burning by the condensedphase mechanism.

Polyurethane: Recent Engineering Contributions

“…The phosphorous based polyols could be mixed with bio-based polyols to prepare highly fire retardancy and superior physico-mechanical rigid PU foams [75]. The study of a rigid PU foam showed that 3,3',4,4'-biphenyltetracarboxylic dianhydride and 9,10-dihydro-9-oxa-(10-glycidoxypropilene)-10-phosphaphenantrene-10-oxide lead to an increase in graphite in the fire residue and the formation of a better barrier to prevent burning by the condensed phase mechanism [76]. Rigid PU modified with microencapsulated red phosphorous, Mg(OH)₂, glass filler and hollow glass bead were prepared and showed that the fire retardancy and the combustion were improved [77].…”

“…After a surface modification EG was introduce also in foams based on PU-imide. The foams exhibited outstanding enhancements compare to that of only pristine EG introduction in compressive strength, thermal stability and flame resistance [86]. Four wood-based wastes were incorporated into rigid bio-based PU foams; these were characterized by thermal and combustion properties.…”

Preparation and mechanism study of intrinsic hard segment flame‐retardant polyurethane foam

“…Recently, many flame retardants on fire resistance of PUF have been reported 11,13–15 . The selection of suitable flame retardants is extremely important for enhancing the flame retardancy of materials.…”

“…[9][10][11][12] Recently, many flame retardants on fire resistance of PUF have been reported. 11,[13][14][15] The selection of suitable flame retardants is extremely important for enhancing the flame retardancy of materials. For example, some researchers have adopted additive flame retardants, such as halogenated compounds, 16 graphite, [17][18][19] phosphorus nitrogen compounds and so forth.…”

Flame retardancy of ceramic‐based rigid polyurethane foam composites

“…3,3′4,4′‐biphenyltetracarboxylic dianhydride and 9,10‐dihydro‐9‐oxa‐(10‐glycidoxypropylene)‐10‐phosph‐phenanthrene‐10‐oxide were incorporated in RPUF for enhancing the flame retardancy of the foam. It was concluded from the results that the incorporated flame retardant showed a small improvement in the thermal properties but the peak of heat release (PHRR) and total heat release (THR) decreased by approximately 20% . Along with the incorporation of flame retardant, some functional filler such as aluminium diethyl phophinate, calcium hypophosphite, and others may also be used to abate the flammability of RPUF.…”