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Novel PEPA-functionalized graphene oxide for fire safety enhancement of polypropylene

View Article: PubMed Central - PubMed

ABSTRACT

Polypropylene (PP) is a general-purpose plastic, but some applications are constrained by its high flammability. Thus, flame retardant PP is urgently demanded. In this article, intumescent flame retardant PP (IFRPP) composites with enhanced fire safety were prepared using 1-oxo-4-hydroxymethyl-2,6,7-trioxa-1-phosphabicyclo [2.2.2] octane (PEPA) functionalized graphene oxide (PGO) as synergist. The PGO was prepared through a mild chemical reaction by the covalent attachment of a caged-structure organic compound, PEPA, onto GO nanosheets using toluene diisocynate (TDI) as the intermediary agent. The novel PEPA-functionalized graphene oxide not only improves the heat resistance of GO but also converts GO and PEPA from hydrophobic to hydrophilic materials, which leads to even distribution in PP. In our case, 7 wt% addition of PGO as one of the fillers for IFRPP composites significantly reduces its inflammability and fire hazards when compared with PEPA, by the improvement of first release rate peak (PHRR), total heat release, first smoke release rate peak (PSRR) and total smoke release, suggesting its great potential as the IFR synergist in industry. The reason is mainly attributed to the barrier effect of the unburned graphene sheets, which protects by the decomposition products of PEPA and TDI, promotes the formation of graphitized carbon and inhibits the heat and gas release.

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The SEM images of intumescent char layer: sample 1 (a), sample 4 (b), sample 7 (c).
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Figure 10: The SEM images of intumescent char layer: sample 1 (a), sample 4 (b), sample 7 (c).

Mentions: The morphology of the residue chars of IFRPP composites after CCT is shown in SEM images in figure 10. The samples with PEPA and PGO produced a continuous, intact and intumescent outer surface, which acts as an insulating barrier, prohibits the oxygen and heat from reaching the underlying substrate due to polyphosphoric acid (decomposition products of PEPA or PGO). Sample 7 is more compact with fewer bubbles appearing on its surface than that of sample 4, suggesting that it could form a better barrier cross-linked network structure through lamellar structure of GO sheets to develop a more compact char layer with better physical barrier ability and mechanical performance.


Novel PEPA-functionalized graphene oxide for fire safety enhancement of polypropylene
The SEM images of intumescent char layer: sample 1 (a), sample 4 (b), sample 7 (c).
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC5036477&req=5

Figure 10: The SEM images of intumescent char layer: sample 1 (a), sample 4 (b), sample 7 (c).
Mentions: The morphology of the residue chars of IFRPP composites after CCT is shown in SEM images in figure 10. The samples with PEPA and PGO produced a continuous, intact and intumescent outer surface, which acts as an insulating barrier, prohibits the oxygen and heat from reaching the underlying substrate due to polyphosphoric acid (decomposition products of PEPA or PGO). Sample 7 is more compact with fewer bubbles appearing on its surface than that of sample 4, suggesting that it could form a better barrier cross-linked network structure through lamellar structure of GO sheets to develop a more compact char layer with better physical barrier ability and mechanical performance.

View Article: PubMed Central - PubMed

ABSTRACT

Polypropylene (PP) is a general-purpose plastic, but some applications are constrained by its high flammability. Thus, flame retardant PP is urgently demanded. In this article, intumescent flame retardant PP (IFRPP) composites with enhanced fire safety were prepared using 1-oxo-4-hydroxymethyl-2,6,7-trioxa-1-phosphabicyclo [2.2.2] octane (PEPA) functionalized graphene oxide (PGO) as synergist. The PGO was prepared through a mild chemical reaction by the covalent attachment of a caged-structure organic compound, PEPA, onto GO nanosheets using toluene diisocynate (TDI) as the intermediary agent. The novel PEPA-functionalized graphene oxide not only improves the heat resistance of GO but also converts GO and PEPA from hydrophobic to hydrophilic materials, which leads to even distribution in PP. In our case, 7 wt% addition of PGO as one of the fillers for IFRPP composites significantly reduces its inflammability and fire hazards when compared with PEPA, by the improvement of first release rate peak (PHRR), total heat release, first smoke release rate peak (PSRR) and total smoke release, suggesting its great potential as the IFR synergist in industry. The reason is mainly attributed to the barrier effect of the unburned graphene sheets, which protects by the decomposition products of PEPA and TDI, promotes the formation of graphitized carbon and inhibits the heat and gas release.

No MeSH data available.


Related in: MedlinePlus