The effects of graphene on the flammability and fire behavior of intumescent flame retardant polypropylene composites at different flame scenarios

Self Cite

Extensive application of epoxy resins (EPs) is highly limited by their intrinsic flammability. Combining EPs with nanoparticles and phosphorus‐nitrogen flame retardants is an effective approach to overcome the drawback. In this work, simultaneous incorporation of octa‐aminophenyl polyhedral oligomeric silsesquioxanes (OapPOSS) and polyphosphazene into EP was reported for the first time. Significantly, reduced peak of heat release rate and UL‐94 V‐0 rating were achieved by tuning suitable ratios of polyphosphazene and OapPOSS for EP composites. During combustion, polyphosphazene promoted char formation and released nonflammable gases such as CO2, NH3, and N2 to dilute oxygen concentration and cool pyrolysis zone. Moreover, numerous phosphorus‐containing species acting as free radical scavengers were generated during degradation. Silicon dioxide evolving from OapPOSS protected char residues from thermal degradation. This study provides a novel method to fabricate high‐performance flame‐retardant EP composites, which have potential applications in the field of electrics and electronics.

Section: Resultsmentioning

confidence: 90%

“…High‐resolution C 1s, O 1s, and N 1s XPS spectra of residual char of EP0 are shown in Figure . In the case of C 1s spectrum, the peak at 284.6 eV belongs to C–H and C–C in the aliphatic and aromatic species . The band at ca.…”

Section: Resultsmentioning

confidence: 99%

A combination of POSS and polyphosphazene for reducing fire hazards of epoxy resin

Shi

Zheng

et al. 2017

Self Cite

“…Figure shows the XPS spectra of char residue of EP, RGO/EP, ZIF‐8/EP, and ZIF‐8/RGO/EP composites after combustion by a cone calorimeter, respectively. As can be seen in C1s spectra, 3 characteristic peaks at 284.7, 285.8, and 287.5 eV belong to C―H and C―C in aliphatic and aromatic species, C―O in ether and/or hydroxyl groups and C═O (carboxylic groups), respectively . Usually, the thermal oxidation resistance of char residue can be measured by the value of Cox/Ca (Cox, oxidized carbons; Ca, aliphatic and aromatic carbons).…”

Section: Resultsmentioning

confidence: 99%

Zeolitic imidazolate frameworks‐8 modified graphene as a green flame retardant for reducing the fire risk of epoxy resin

Wang

et al. 2018

A novel hybrid material of ZIF‐8/RGO (zeolitic imidazolate frameworks‐8 loaded the surface of graphene) was synthesised by a simple method and characterized. Then, ZIF‐8/RGO was added into epoxy resin (EP), and the flame retardancy and smoke suppression of the EP composites were studied. Compared with pure EP, the peak heat release rate and the total heat release of the EP composites were reduced remarkably, and their LOI and UL94 vertical burning rating were also improved. In addition, their smoke production rate and total smoke production were decreased drastically. The improved flame retardancy and smoke suppression were mainly attributed to the physical barrier effect of graphene. Meanwhile, the metal oxide decomposed from ZIF‐8 could contribute to the production of char residue and enhance the compactness of the char layer.

“…Intumescent flame retardant (IFR) has attracted a great deal of attention because of its low smoke, non‐toxicity, anti‐dripping, and environmental friendly characteristics . The mechanism of IFR refers to the formation of multicellular swollen char on the surface of the matrix under heating beyond a critical temperature, which acts as excellent insulation barrier against heat transfer from the heat flux/flame to the unburned matrix . A typical IFR mainly comprises 3 components: an acid source, a charring agent, and a blowing agent .…”

Section: Introductionmentioning

confidence: 99%

Synthesis of a novel hyperbranched and phosphorus‐containing charring‐foaming agent and its application in polypropylene

Zhu

Cui

et al. 2018

Self Cite

In this work, a novel hyperbranched and phosphorus‐containing triazine derivative (HPCFA) is synthesized. HPCFA is used as charring‐foaming agent and combined with ammonium polyphosphate (APP) as intumescent flame retardant to flame retard polypropylene (PP). PP/HPCFA/APP composite can achieve limited oxygen index value of 31% and pass UL 94V‐0 rating by addition of 20 wt% HPCFA/APP (1/2, w/w). Besides, HPCFA is compared with another hyperbranched charring‐foaming agent (HCFA). HPCFA and HCFA have similar chemical structure, and their only difference is that HPCFA has phosphorus‐containing unit in the main chain compared with HCFA. HPCFA/APP system exhibits superior flame retardancy compared with HCFA/APP system. Char residue analysis demonstrates that HPCFA/APP system can form denser and more compact char layer in comparison with that of HCFA/APP system.