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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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XPS spectra of GO and PGO (a), higher resolution C1s spectra of GO (b) and PGO (c). The curves of PGO (a) is offset vertically by 10 000 a.u.
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Figure 3: XPS spectra of GO and PGO (a), higher resolution C1s spectra of GO (b) and PGO (c). The curves of PGO (a) is offset vertically by 10 000 a.u.

Mentions: After modification, the removal of oxygen groups and the formation of chemical bonds on the surface of GO were confirmed by XPS spectra. Figure 3 shows the XPS spectra of GO and PGO in a binding energy range of 0–1100 eV (figure 3(a)), and C1s scan of GO and PGO (figures 3(b) and (c)). As shown in figure 3(a), some peaks are observed at around 189.9 eV (P2s), 285.2 eV (C1s), 399.6 eV (N1s) and 531.1 eV (O1s). But only two peaks are observed at around 285.2 eV (C1s) and 531.1 eV (O1s) in the spectrum of GO, which indicates that PGO contained oxygen, nitrogen, phosphorus, and carbon. The C1s scan of GO and PGO (figures 3(b) and (c)) display the presence of four kinds of carbon in the GO and PGO: C=O, C–O–C, C–OH and C–C in the graphitic domain, and the peaks of C–O–P and C–N appear in the curve of the PGO. In comparison, the C–O–C signal is increased after the functionalization, however, the C–OH is decreased, which indicates the C–OH on the surface of the GO is reduced into C–O–C in the process of functionalization reaction.


Novel PEPA-functionalized graphene oxide for fire safety enhancement of polypropylene
XPS spectra of GO and PGO (a), higher resolution C1s spectra of GO (b) and PGO (c). The curves of PGO (a) is offset vertically by 10 000 a.u.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Figure 3: XPS spectra of GO and PGO (a), higher resolution C1s spectra of GO (b) and PGO (c). The curves of PGO (a) is offset vertically by 10 000 a.u.
Mentions: After modification, the removal of oxygen groups and the formation of chemical bonds on the surface of GO were confirmed by XPS spectra. Figure 3 shows the XPS spectra of GO and PGO in a binding energy range of 0–1100 eV (figure 3(a)), and C1s scan of GO and PGO (figures 3(b) and (c)). As shown in figure 3(a), some peaks are observed at around 189.9 eV (P2s), 285.2 eV (C1s), 399.6 eV (N1s) and 531.1 eV (O1s). But only two peaks are observed at around 285.2 eV (C1s) and 531.1 eV (O1s) in the spectrum of GO, which indicates that PGO contained oxygen, nitrogen, phosphorus, and carbon. The C1s scan of GO and PGO (figures 3(b) and (c)) display the presence of four kinds of carbon in the GO and PGO: C=O, C–O–C, C–OH and C–C in the graphitic domain, and the peaks of C–O–P and C–N appear in the curve of the PGO. In comparison, the C–O–C signal is increased after the functionalization, however, the C–OH is decreased, which indicates the C–OH on the surface of the GO is reduced into C–O–C in the process of functionalization reaction.

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