Flame Retardancy Of Rigid Polyurethane Foam Research Articles

Coastal Building Energy Conservation Based on Rigid Polyurethane Foam External Wall Insulation Technology

Zhao, X., 2020. Coastal building energy conservation based on rigid polyurethane foam external wall insulation technology. In: Al-Tarawneh, O. and Megahed, A. (eds.), Recent Developments of Port, Marine, and Ocean Engineering. Journal of Coastal Research, Special Issue No. 110, pp. 247–250. Coconut Creek (Florida), ISSN 0749-0208.Energy saving technology of coastal buildings is a hot spot. In this paper, flame-retardant rigid polyurethane foam (RPF) is prepared by adding straw as enhancer straw and water as foaming agent. Then the relationship between structure and properties of RPF, effect of enhancer and additive flame retardant on properties of RPF are studied by some characterization methods. The addition of the enhancer straw can improve the mechanical properties of RPF in a certain range. When the amount is too large, it will produce a certain pulverization, which will reduce the mechanical properties. In this study, a complete application scheme of RPF insulation products in roof has been formed, providing an energy-saving way for RPF insulation products.

The Synergistic Effect of Ionic Liquid-Modified Expandable Graphite and Intumescent Flame-Retardant on Flame-Retardant Rigid Polyurethane Foams.

In this study, a nitrogen–phosphorus intumescent flame-retardant 3-(N-diphenyl phosphate) amino propyl triethoxy silane (DPES), the ionic liquid (IL) of 1-butyl-3-methyl-imidazole phosphate, and a phosphorous-containing ionic liquid-modified expandable graphite (IL-EG), were synthesized, and their molecular structures were characterized. The flame-retardant rigid polyurethane foams (RPUFs) were compounded with synergistic flame-retardant IL-EG/DPES to study the effects of the combination IL-EG and DPES on the pore structure, mechanical properties, thermal decomposition behavior and thermal decomposition mechanism of RPUF. The results showed that IL-EG/DPES had good thermal stability, and an excellent expansibility and char yield. The flame-retardant RPUF, modified with IL-EG and DPES at the ratio of 1:1, had a relatively uniform pore size, the highest compressive strength, and an excellent flame-retardant performance due to the form interwoven hydrogen bonds between IL-EG and DPES, as well as the new synergistic flame-retardant coating on the RPUF surface to restrict the transfer of gas or heat into the PU matrix.

Flame-retardant system for rigid polyurethane foams based on diethyl bis(2-hydroxyethyl)aminomethylphosphonate and in-situ exfoliated clay

The flame-retardant rigid polyurethane foams (FR-RPUFs) with organoclay (OMMT) and/or diethyl bis(2-hydroxyethyl)aminomethylphosphonate (DBHP) were prepared by free foaming. The modification effect of OMMT was studied by X-ray diffraction (XRD), Fourier transform infrared spectrometry (FTIR) and thermogravimetric analysis (TGA). The dispersion state of OMMT in RPUF was evaluated by XRD and transmission electron microscopy (TEM). The compressive strength and micro-morphology of neat RPUF (N-RPUF) and FR-RPUFs were investigated by universal testing machine and scan electronic microscopic (SEM). The flame retardancy of FR-RPUFs was explored by limiting oxygen index (LOI), vertical burning test (UL94) and cone calorimeter test (CCT). These results indicated that OMMT was exfoliated or intercalated during the synthesis of FR-RPUFs. The incorporation of OMMT endowed RPUF smaller cell size, higher density and compressive strength. Compared to the flame-retardant effect of OMMT or DBHP alone, the OMMT/DBHP system significantly raised LOI value and UL94 rating, reduced heat release rate and total heat release, and increased char yields. During combustion of FR-RPUFs, DBHP boosted the formation of phosphorus-rich char layer, and the char layer was reinforced by nano-dispersed clay sheets to create a physical barrier that can insulate the underlying polymer from heat and slow oxygen uptake and the escape of volatile ingredients produced by polymer degradation. The results from pyrolysis-gas chromatography/mass spectroscopy (Py-GC/MS) confirmed that the PO⋅ and PO2· radicals pyrolyzed by DBHP can be released into gaseous phase to terminate free radical chain reaction of combustion. The results from TGA indicated that OMMT and DBHP can increase residues. Also, the kinetics analysis demonstrated that OMMT can improve the thermal stability of RPUF. Therefore, a bi-phase flame-retardant effect of OMMT/DBHP system in RPUF was achieved.

The influence of carbon-encapsulated transition metal oxide microparticles on reducing toxic gases release and smoke suppression of rigid polyurethane foam composites

The rapid development and massive consumption of rigid polyurethane foams (RPUF) has drawn attention to their fire safety related problems, such as the heat release and notable generation of smoke and toxic gases in fire. Three novel types of carbon-encapsulated transition metal oxide microparticles, Cu@C, Fe2O3@C and Cu2O@Fe2O3@C, were prepared via a simple hydrothermal method in this research. Potential smoke and toxicity suppression by the as-prepared carbon-encapsulated hybrids in flame-retardant RPUF composites with ammonium polyphosphate (APP) and dimethylmethylphosphonate (DMMP) were investigated. Compared with pure RPUFs, the peak heat release rate (pHRR) value of RPUF/A5-D5/5.0Fe2O3@C decreased by 40.5%, indicating the obvious improved flame retardancy. Besides, the related mechanisms of smoke suppression and toxic based on the catalytic effect of transition metal oxide was also proposed on the basis of experiment results.

Synthesis of a novel phosphorus and nitrogen-containing flame retardant and its application in rigid polyurethane foam with expandable graphite

A novel phosphorus and nitrogen containing flame retardant named 1,4-bis(Diethyl methylenephosphonate) piperazine (BDEMPP) was synthesized. The chemical structures of BDEMPP were determined by Fourier transform infrared spectrum (FTIR), nuclear magnetic resonance (NMR) and gas chromatography-mass spectrometry (GC-MS). The flame retardant rigid polyurethane foams (FR-RPUFs) were prepared by one-pot and free foaming with incorporating BDEMPP/expanded graphite (EG) with polyether polyol and polymethylene polyphenyl isocyanate. The limit oxygen index (LOI), vertical burning (UL94) and cone calorimeter (CONE) test showed that the fire-retardant properties were improved due to the barrier effect of EG and residual char. With addition of 10 wt % EG and 15 wt % BDEMPP, RPUF/10EG/15BDEMPP passed UL94 V-0 with the LOI value of 25.7%. The thermogravimetric analysis (TGA) results revealed that the initial decompose temperature (T5%) of RPUF/10EG/15BDEMPP was decreased compared with pure RPUF. However, the yield of residual char was increased from 0.35% for pure RPUF to 30.52% for RPUF/10EG/15BDEMPP at 800 °C. EG and BDEMPP had a slight influence on density and compression strength. The density and compression strength of pure RPUF was 45.42 kg m−3 and 213 kPa. As for RPUF/10EG/15BDEMPP, the density and compression strength was 44.18 kg m−3 and 180 kPa. The morphology and composition of residual char were investigated. The results demonstrated that the intact, compact and thick residual char with abundant of phosphorus and nitrogen was formed to enhance the flame retardancy and smoke suppression.

Steel slag waste combined with melamine pyrophosphate as a flame retardant for rigid polyurethane foams

To explore the potential application of industrial waste, steel slag powder in combination with melamine pyrophosphate (MPP) was adopted to improve the flame retardancy of rigid polyurethane foam (RPUF). The incorporation of steel slag slightly reduced the thermal conductivity of the resulting flame-retardant RPUF samples. The addition of MPP and/or steel slag did not significantly alter the thermal stability in terms of T-10% and Tmax but did obviously increase the T-50% value, suggesting the improved thermal resistance of the residues. The coaddition of MPP and steel slag into RPUF resulted in higher LOI values and lower peak heat release rates than the samples incorporating either MPP or steel slag alone. The superior flame retardancy could be attributed to MPP promoting char formation, which then acted as a barrier at the beginning of RPUF thermal decomposition; simultaneously, the thermally stable inorganics in the steel slag powder strengthened the thermal resistance of this char layer.

Highly Effective Flame-Retardant Rigid Polyurethane Foams: Fabrication and Applications in Inhibition of Coal Combustion.

The extemporaneous combustion of coal remains a major threat to safety in coal mines because such fire accidents result in casualties and significant property loss, as well as serious environmental pollution. This work proposed the fabrication of flame-retardant rigid polyurethane foam (RPUF) containing expandable graphite as char expander/sealant with melamine phosphosphate and 2-carboxyethyl (phenyl)phosphinic acid as char inducer and radical trapping agents. The as-prepared RPUF successfully inhibited coal combustion by forming thermally stable high graphitic content expandable intumescent char sealing over the coal. The RPUF achieved UL-94 V-0 rating in addition to significant reductions in peak heat release, total heat release, and CO and CO2 yields. The external and the internal residual char structure was studied by X-ray photoelectron spectra, Raman spectroscopy, and real-time Fourier transform infrared spectra techniques, and a flame-retardant mode of action has been proposed. This work provides important insight into a facile fabrication of highly efficient and economical flame-retardant RPUF to inhibit the spontaneous combustion of coal.

Gamma-irradiation-induced micro-structural variations in flame-retardant polyurethane foam using synchrotron X-ray micro-tomography.

Flame-retardant polyurethane foams are potential packing materials for the transport casks of highly active nuclear materials for shock absorption and insulation purposes. Exposure of high doses of gamma radiation causes cross-linking and chain sectioning of macromolecules in this polymer foam, which leads to reorganization of their cellular microstructure and thereby variations in physico-mechanical properties. In this study, in-house-developed flame-retardant rigid polyurethane foam samples were exposed to gamma irradiation doses in the 0-20 kGy range and synchrotron radiation X-ray micro-computed tomography (SR-µCT) imaging was employed for the analysis of radiation-induced morphological variations in their cellular microstructure. Qualitative and quantitative analysis of SR-µCT images has revealed significant variations in the average cell size, shape, wall thickness, orientations and spatial anisotropy of the cellular microstructure in polyurethane foam.

Synthesis of reactive phenylphosphoryl glycol ether oligomer and improved flame retardancy and mechanical property of modified rigid polyurethane foams

A novel reactive phenylphosphoryl glycol ether oligomer (PPGE) was synthesized to improve the flame retardancy of rigid polyurethane foam (RPUF). The PPGE segments in RPUF simultaneously enhanced its compressive modulus and flame retardancy. With the incorporation of 2% phosphorous weight content in RPUF, the limiting oxygen index value of 2%PRPUF improved from 20.0% of neat RPUF to 24.5%. The cone calorimeter test results demonstrated that the total heat release and peak heat release rate values of 2%PRPUF decreased, approximately 24% and 18% lower than those of neat RPUF, respectively. The combination of 2%PRPUF with expanded graphite (EG) efficiently reduced the flame spread rate and smoke toxicity of flame retardant RPUF. The flame-retardant mechanism of the 2%PRPUF/EG demonstrated that the synergistic effect of phosphorous-containing radical inhibition and the barrier of expansive char residue consequently led to a highly efficient flame retardancy. The reactive phosphorous-containing oligomer is promising in the development of high-performance flame-retardant thermal insulation RPUFs.

Density Effect on Flame Retardancy, Thermal Degradation, and Combustibility of Rigid Polyurethane Foam Modified by Expandable Graphite or Ammonium Polyphosphate.

The current study aims at comparatively investigating the effect of apparent density on flame retardancy, thermal degradation and combustion behaviors of rigid polyurethane foam (RPUF), RPUF/ expandable graphite (EG) and RPUF/ ammonium polyphosphate (APP). A series of RPUF, RPUF/EG and RPUF/APP samples with different apparent densities (30, 60 and 90 kg/m3) were prepared. The flame retardancy, thermal degradation, and combustion behaviors of each sample were investigated. Limiting oxygen index (LOI) results indicated that increasing apparent density was beneficial to the flame retardancy of all foam systems. The effect of apparent density on the enhancement of flame retardancy followed the sequence of RPUF < RPUF/APP < RPUF/EG. Thermogravimetric analysis (TGA) results showed that an increase in the apparent density can cause more weight loss in the first degradation stage and less weight loss in the second degradation stage for all foam systems. The combustion behaviors also showed significant differences. The samples with a higher apparent density showed a longer duration of heat release and higher total heat release (THR). The findings in this study demonstrated that apparent density played an important role in flame retardancy, thermal degradation, and combustion behaviors of RPUF, which must be paid more attention in the studies of flame-retardant RPUF.

Ammonium polyphosphate modified with β-cyclodextrin crosslinking rigid polyurethane foam: Enhancing thermal stability and suppressing flame spread

Ammonium polyphosphate modified with β-Cyclodextrin (β-CD) as intumescent flame retardants was prepared and then incorporated in rigid polyurethane foam (RPUF) to improve thermal stability and flame retardancy. Scanning electron microscope (SEM), Transmission electron microscope (TEM), Fourier-transform infrared (FTIR) spectra and X-ray photoelectron spectroscopy (XPS) were used to characterize the modified APP (β-APP). The results showed that the surface of β-APP was covered of β-CD and the dispersibility of β-APP in substrate was improved apparently. In addition, the influence of β-APP on the cell structure, crosslink density, thermal stability and flame retardancy of RPUF were investigated. The results showed that β-APP was able to promote cellular distribution of RPUF into smaller and homogeneous. The results of dynamic thermomechanical analysis (DMA) and thermogravimetric analysis (TGA) indicated that the glass transition temperature (Tg) and crosslink density of β-APP/RPUF increased obviously, and the thermal stability of β-APP/RPUF was better than other FR-RPUFs. During combustion, flame spreading speed of 25 wt%β-APP/RPUF reduced by 67.3% relative to pure RPUF and extinguish time decreased to 2.1s with the most complete inner char and the most dense outside char. In addtion, peak heat release rate (PHRR) of the sample decreased by 43.8% compared to pure RPUF. Therefore β-APP exhibited a prominent charring property and flame-retardant effect in condensed phase for RPUF.

Thermal Degradation and Flame Retardant Mechanism of the Rigid Polyurethane Foam Including Functionalized Graphene Oxide.

A flame retardant rigid polyurethane foam (RPUF) system containing functionalized graphene oxide (fGO), expandable graphite (EG), and dimethyl methyl phosphonate (DMMP) was prepared and investigated. The results show that the limiting oxygen index (LOI) of the flame-retardant-polyurethane-fGO (FRPU/fGO) composites reached 28.1% and UL-94 V-0 rating by adding only 0.25 g fGO. The thermal degradation of FRPU samples was studied using thermogravimetric analysis (TG) and the Fourier transform infrared (FT-IR) analysis. The activation energies (Ea) for the main stage of thermal degradation were obtained using the Kissinger equation. It was found that the fGO can considerably increase the thermal stability and decrease the flammability of RPUF. Additionally, the Ea of FRPU/fGO reached 191 kJ·mol−1, which was 61 kJ·mol−1 higher than that of the pure RPUF (130 kJ·mol−1). Moreover, scanning electron microscopy (SEM) results showed that fGO strengthened the compactness and the strength of the “vermicular” intumescent char layer improved the insulation capability of the char layer to gas and heat.

Eco-Friendly Flame-Retardant Additives for Polyurethane Foams: A Short Review

Polyurethane (PU) materials are extensively used in the construction industry as core material insulation for sandwich panel application, such as wall cladding, structure insulation and roof panel. Demands on PU application have escalated given its significant advantages to reduce energy consumption. Meanwhile, rigid PU (RPU) foams are combustible materials characterized by rapid flame spread, high heat-release rates, and ability to produce large quantities of toxic gases in original form. Thus, flame-retardant (FR) additives are used to improve the thermal properties of PU. However, some commercial additives used today have are hazardous to humans and the environment, and their extensive application is limited by their negative effects on polymer mechanical properties. Accordingly, identifying materials that are environmentally friendly and harmless to humans has become urgent. Some alternative additives that are gaining research interest are clay and fly ash, which are natural and recyclable resources that can enhance the FR properties of other polymers. However, room for improvement is always present as the related technology is continually being developed. This review focuses on studies aiming to enhance the flame retardancy of RPU foam using fly ash and local clay as additives.

The effects of N,N-(pyromellitoyl)-bis-l-phenylalanine diacid ester glycol on the flame retardancy and physical–mechanical properties of rigid polyurethane foams

Flame-retardant rigid polyurethane foams incorporating N,N-(pyromellitoyl)-bis-l-phenylalanine diacid ester glycol have been prepared. After adding N,N-(pyromellitoyl)-bis-l-phenylalanine diacid ester glycol, the density and compressive strength of the polyurethane foams were seen to decrease. The flame retardancy of the polyurethane foams has been characterized by limiting oxygen index, upper limit–94, and cone calorimeter tests. The polyurethane foam with 2.27 wt% N,N-(pyromellitoyl)-bis-l-phenylalanine diacid ester glycol gave a highest limiting oxygen index of 33.4%, and the peak heat release rate of polyurethane foam reduced to 19.5 kW/m2 from 47.6 kW/m2 of PU-0 without N,N-(pyromellitoyl)-bis-l-phenylalanine diacid ester glycol. Upper limit–94 revealed N,N-(pyromellitoyl)-bis-l-phenylalanine diacid ester glycol did not change the burning rating, and all polyurethane foams had passed V-0 rating. The thermal stability of polyurethane foams has been investigated by thermogravimetric analyzer. N,N-(pyromellitoyl)-bis-l-phenylalanine diacid ester glycol significantly increased the initial decomposition temperature of polyurethane foams and their residues. In addition, the morphology of residual char from the flame-retarded polyurethane foams after cone calorimeter tests has also been characterized by digital photographs. The results indicated that N,N-(pyromellitoyl)-bis-l-phenylalanine diacid ester glycol significantly enhanced the strength and compatibility of the char layer formed by the polyurethane foams. These results indicate that N,N-(pyromellitoyl)-bis-l-phenylalanine diacid ester glycol can improve both the quality and quantity of the char, which has a significant effect on the flame-retardant properties of the foam.

Inherently flame-retardant rigid polyurethane foams with excellent thermal insulation and mechanical properties

In an effort to overcome issues encountered in additive flame retardants for rigid polyurethane foams (RPUFs), a novel reactive flame-retardant triol (TDHTPP) based on a triazine and phosphate structure was designed and synthesized. This triol was chemically incorporated in the main chains of RPUFs as a chain-extender to prepare inherently flame-retardant RPUFs. TDHTPP showed good solubility in the polyols (polyol 4110 and PEG 400) of RPUF, making it convenient for industrial fabrication, such as in spay foaming. Excellent compatibility of TDHTPP with the polymer matrix endowed flame-retardant RPUFs (FR-RPUFs) much higher compressive strength than that of the neat RPUF, and a low thermal conductivity of ∼0.03 W/(m·K). Notably, with only 5 wt% of TDHTPP incorporated, the resultant RPUF displayed a UL-94 V-0 rating and more importantly, exhibited a great persistent flame retardancy during thermal accelerated aging tests at 140 °C for 96 h. Further characterization revealed that TDHTPP possessed both vapor-phase and condensed-phase flame-retardant behaviors, in which, vapor-phase action was dominant. This work provides a facile route to synthesize RPUFs with persistent flame retardancy, excellent thermal insulation and mechanical properties.

A flame retardant rigid polyurethane foam system including functionalized graphene oxide

A functionalized graphene oxide (fGO) was prepared by graphene oxide (GO), boric acid and 3‐aminopropyltriethoxysilane in an ethanol aqueous solution using ultrasonic agitation. Its structure was characterized by the Fourier transform infrared (FTIR), X‐ray diffraction (XRD), thermogravimetric analysis (TG), and elemental analysis. Subsequently, the fGO was incorporated into the flame‐retardant‐polyurethane (FRPU) system, in which fGO as a synergist and reinforcing agent, expandable graphite (EG), and dimethyl methylphosphonate (DMMP) as flame retardants, to improve its the flame‐retardancy and mechanical properties, evidenced by the limiting oxygen index (LOI), vertical burning test (UL‐94) test and the cone calorimeter test (CONE). The LOI value of FRPU/fGO composites reached 28.1% by addition of 0.25 phr fGO and 10 phr EG/DMMP, and its UL‐94 test reached V‐0 rating. The CONE results revealed that fGO could significantly enhance flame retardant properties of FRPU composites, and the peak heat release rate (PHRR) values value of FRPU/fGO remarkably reduced by 32.9%. Moreover, fGO indeed enhanced the mechanical properties of rigid polyurethane foam (RPUF). POLYM. COMPOS., 40:E1274–E1282, 2019. © 2018 Society of Plastics Engineers

Highly-efficient reinforcement and flame retardancy of rigid polyurethane foam with phosphorus-containing additive and nitrogen-containing compound

Flame retardant rigid polyurethane foam (RPUF) with a reactive melamine-derived polyol (MADP) and 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) were fabricated through free-rise technique. The thermal stability and fire behaviors of RPUF were investigated by thermogravimetric analysis (TGA), limiting oxygen index (LOI), and cone calorimeter. In comparison with the results of RPUF and RPUF/MADP, RPUF/MADP-DOPO displayed higher compressive strength, owing to the two stiff phenyl groups of DOPO. Moreover, with only 7.5 wt % MADP and 7.5 wt % DOPO loading, the MADP/DOPO system endowed RPUF with enhanced char formation, increased LOI value of 28.5% and reduced heat release. Scanning electron microscope (SEM) images, X-ray photoelectron spectroscopy (XPS) analysis and Raman spectra of the char residues suggested that the formation of compact, continuous char layer. The thermal degradation was characterized using thermogravimetric analysis/infrared spectrometry (TG-IR) and chemical structure changes during the thermal degradation were monitored by real time Fourier transform infrared (RT-FTIR), these results demonstrated that the partial phosphorus from DOPO remained in the residual char, but the introduction of MADP significantly promoted generating more stable aromatic structure and enhanced the strength of the char layer formed. Furthermore, MADP facilitated the formation of more H2O and CO2 and diluted the flammable gases in gaseous phase. Based on the analysis, the introduction of MADP/DOPO can endowed excellent flame retardancy to RPUF depending on bi-phase flame-retardant mechanism.

Highly flame retardant and bio‐based rigid polyurethane foams derived from orange peel oil

Limonene dimercaptan (LDM), an orange peel oil‐based derivative, and glycerol‐1‐allyl ether (GAE) were used to synthesize bio‐based polyol (LDM‐GAE) using one step photochemical thiol‐ene reaction. The synthesized polyol was used to prepare flame retardant polyurethane foams using dimethyl methyl phosphonate (DMMP) as an additive flame retardant (AFR) and a new bromine containing reactive flame retardant (RFR) derived from 2,4,6‐tribromophenol. Both flame retardants lead to rigid polyurethane foams with excellent physical‐mechanical properties with a short self‐extinguishing time (7.5 and 12.8 sec for DMMP and bromine‐based foams, respectively) and with low weight loss after burning. The reactive bromine polyol lead to rigid polyurethanes with better physical‐mechanical properties than those of foams based on AFR with phosphorous, but the flame retardant properties of foams prepared using AFR are superior to the foams prepared using bromine polyol (RFR). Low addition of DMMP is sufficient to reduce the flammability of polyurethane foam without compromising its physical‐mechanical properties. These flame retardant rigid polyurethane foams based on limonene dimercaptan can be used in all applications of rigid polyurethane foams especially where flammability is an issue such as for insulation of buildings. POLYM. ENG. SCI., 58:2078–2087, 2018. © 2018 Society of Plastics Engineers

Mechanical Properties and Flame Retardancy of Rigid Polyurethane Foams Containing SiO2 Nanospheres/Graphene Oxide Hybrid and Dimethyl Methylphosphonate

ABSTRACTHalogen-free flame-retardant rigid polyurethane foams were prepared using the combination of SiO2 nanospheres/graphene oxide hybrid and a phosphorus-containing flame retardant, dimethyl methylphosphonate. The flame retardancy, mechanical, and thermal properties of flame-retardant rigid polyurethane foams containing dimethyl methylphosphonate and SiO2 nanospheres/graphene oxide were investigated. The results demonstrated that the combination of dimethyl methylphosphonate and SiO2 nanospheres/graphene oxide enhanced flame retardant and mechanical properties of rigid polyurethane foam greatly compared with pure rigid polyurethane foam and dimethyl methylphosphonate-modified foam. Morphological study indicated that the partial substitution of dimethyl methylphosphonate with SiO2 nanospheres/graphene oxide led to smaller cell sizes and more uniform cell sizes of dimethyl methylphosphonate-modified rigid polyurethane foams.

Synthesis and characterization of flame retardant rigid polyurethane foam based on a reactive flame retardant containing phosphazene and cyclophosphonate

A reactive flame retardant hexa-(5,5-dimethyl-1,3,2- dioxaphosphinane-hydroxyl-methyl-phenoxyl)-cyclotriphosphazene (HDPCP) was synthesized by using 5,5-dimethyl-1,3,2-dioxaphosphinane 2-oxide and hexa-(4-aldehyde-phenoxy)-cyclotriphosphazene via P-H addition reaction. And it was used to prepare flame retardant rigid polyurethane foams (FR-RPUFs). The effect of flame retardant HDPCP on physical-mechanical, thermal degradation and fire behavior properties of FR-RPUFs system has been investigated. The results suggested that HDPCP showed no obviously negative influence on physical-mechanical property of RPUF. The thermal stability and char residue at 700 °C of RPUF were enhanced by introducing HDPCP. HDPCP is benefit to improve flame retardance of RPUF. The limiting oxygen index (LOI) increased from 19 to 25% with incorporation of 25% HDPCP. Moreover, the peak heat release rate (PHRR), total heat release rate (THR), total smoke rate (TSR) and total smoke production (TSP) of RPUFs decreased due to a good char-forming ability of HDPCP.