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The combustion of polystyrene (PS) releases enormous amounts of smoke and heat, which seriously affects individuals and property safety. This research employed a porous metal–organic framework (P-Fe-MOF) with excellent adsorption properties to fix 1,1'-bis(diphenylphosphino)ferrocene (BDF) into its porous channels to form a novel flame-retardant system. The peak heat release rate (PHRR) of the neat PS is reduced by 49.3% (from 1128 to 572 kW m−2) with the addition of 3 mass% of D-Fe-MOF, while the time to reach the peak is delayed form 170 to 250 s. Additionally, there is an obvious enhancement in thermal stability. The temperature at initial mass losses is significantly delayed from 331 °C for bulk PS to 379 °C for PS/D-Fe-3.0. And the char residue at 700 ℃ is increased from 1.27 to 3.24 mass%. Compared with pure PS, the char residue of PS/D-Fe-MOF is continuous and dense due to the excellent catalytic performance of D-Fe-MOF in the combustion of composites. This research presents a new flame-retardant design strategy and reduces the fire risk of PS, which provides valuable enlightenment for broadening the application field of MOF and improving the comprehensive properties of polymers. [ABSTRACT FROM AUTHOR]

The effects of adhesive (layer) on fire performances of structural insulated panel (SIP) have been mostly ignored. This research studied modifications to the epoxy resin adhesive (EA) with expandable graphite (EG), ammonium polyphosphate (APP) and calcium carbonate (CaCO3) to prepare an intumescent flame-retardant epoxy resin adhesive (FREA) which was applied to expanded polystyrene (EPS), a typical core material of SIPs. It was found that the FREA had a char yield of 33% which was 7.6 times of that of EA and a higher viscosity than EA. The limiting oxygen index reached a maximum of 37.7% and UL94 passed the V-0 rating when the EPS was coated with FREA, of which the fire performance was even better than flame-retardant EPS. Additionally, the heat release rate, production rates of CO, CO2 and soot and sample back temperatures were all reduced compared to the EPS coated with EA. Avoiding the sample surface recession in the cone calorimeter, the custom-made spray gun system proves that the FREA can significantly increase the ignition time and lead to self-extinguishment. The degradation products of APP crosslink with CaCO3 to produce phosphates which bond with expanded EG forming the char layer to prevent heat and flame. The use of flame-retardant adhesives can lead to a sufficient fire safety level for the core material without affecting its functions. [ABSTRACT FROM AUTHOR]

Cables are the most common combustibles in nuclear power plants (NPPs) and cable fires are the one of main threaten to the safety of NPPs. Fire characteristics and fire hazards for two typical cables used in NPPs were comparatively studied based on cone calorimeter and cable tray fire tests. The heat release rate (HRR) curves show different patterns, two-peaks and three-peaks for NPP and conventional flame retardant cables, respectively. This difference is attributed to the fire barrier, which distinguishes the burning of sheath and insulation. Moreover, the maximum value of HRR for conventional flame retardant cable is much higher than NPP flame-retardant cable, and the difference is 108 kW m−2. The time from first peak to second peak for NPP flame-retardant cable is approximately four times as conventional flame retardant cable. Based on cable tray fire, the burning time after burner off is much longer for conventional flame retardant cable and its total mass loss is 0.52 kg, which are three times and five times as much as NPP flame-retardant cable, respectively, and it has a self-sustaining stage during cable burning. The above indicates that the NPP flame-retardant cable has less sustained damage, fire development rate and overall fire hazard. In addition, spacing has little effect on the burning time of sheath, but the burning of insulation layer is promoted, the time from first peak to second peak decreases with the increase in spacing. However, the influence of spacing is non-monotonous in cable tray fire, and the burning of cables with 10 mm spacing has higher fire hazard with a maximum mass loss rate. [ABSTRACT FROM AUTHOR]

The surface of ammonium polyphosphate is modified by layered silicates (kaolinite or functionalized kaolinite). The thermogravimetric analysis data confirm that the layered silicates significantly strengthen the thermal stability of polypropylene (PP) and increase the char residue. Fire safety of PP containing different percentages of modified ammonium polyphosphate and charring–foaming agent is assessed by using limiting oxygen index (LOI) and UL-94 vertical combustion. The addition of layered silicates in polymers can effectively enhance the flame-retardant properties including the enhancements in UL-94 rating and LOI results. The flame-retardant mechanism and model are described based on the results of thermal degradation and char residue analysis. [ABSTRACT FROM AUTHOR]

The possibility of layered melamine-phytate (MEL-PA) as an efficient synergist for intumescent flame retardant (IFR) is explored. The synergistic effects of MEL-PA on polypropylene (PP)/IFR composites are investigated in terms of flammability tests and combustion under forced-flaming condition. The addition of MEL-PA can effectively improve limited oxygen index (LOI) of PP composites. When 2 mass% MEL-PA is incorporated, the LOI value is enhanced from 33.0 to 35.1%. In addition, fire-retardant performance is increased with the addition of MEL-PA. The heat and smoke releases of PP/IFR are greatly reduced by MEL-PA. When IFR is partially replaced by 0.5, 1.0 and 2.0 mass% MEL-PA, total smoke production values are decreased by 27.2%, 34.8% and 57.6%, respectively. Raman spectra analysis indicates that the adding of MEL-PA results in higher graphitization degree of char layer. This work proves that MEL-PA and IFR have a good synergistic effect on flame-retardant PP. [ABSTRACT FROM AUTHOR]

Polystyrene (PS) composites with different loading level and proportions of CNAPP20 [i.e., ammonium polyphosphate (APP) wrapped graphitic carbon nitride (g-C3N4), where mass ratio of g-C3N4 to the CNAPP was 20%] to aluminim phosphinates were fabricated. The results indicated that the additives had good interfacial interaction with PS matrix. It is noted that only the PS-1 achieved the UL-94 V-0 rating, and value of limited oxygen index was also the highest among all the composites. The peak of heat release rate (pHRR) and total heat release of all the composites were greatly reduced as compared to those of virgin PS (77.5% decrease in pHRR for PS-1). Combining CNAPP20 with DAHPi (i.e., aluminim diethylphosphinate) induced the formation of a cohesive and uniform carbonaceous residue. In addition, the concentration of carbon dioxide, smoke and carbon monoxide was reduced upon incorporation of CNAPP20 and DAHPi. The property improvements were attributed to the explanations that the formed continuous and dense char residues acted as protecting layers to prevent the heat and mass permeation, and that the evolved gas diluted the oxygen, which retarded the further combustion of flammable compounds. Also, the generated free-radical scavengers retarded polymeric chain breakage. [ABSTRACT FROM AUTHOR]

Graphene oxide (GO) is modified by melamine (MA) via the strong π- π interactions, hydrogen bonding, and electrostatic attraction. PP composites are prepared by melt compounding method, and GO/functionalized graphene oxide (FGO) is in situ thermally reduced during the processing. The results of scanning electron microscopy and transmission electron microscopy indicate that FGO nanosheets are homogeneously dispersed in polymer matrix with intercalation and exfoliation microstructure. The FGO/PP nanocomposite exhibits higher thermal stability and flame retardant property than those of the GO counterpart. During the thermal decomposition, the intercalated MA is condensed to graphitic carbon nitride (g-CN) in the confined micro-zone created by GO nanosheets. This in situ formed g-CN provides a protective layer to graphene and enhances its barrier effect. The heat release rate and the escape of volatile degradation products are reduced in the FGO-based nanocomposites. [ABSTRACT FROM AUTHOR]