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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.

No MeSH data available.


Raman spectra of GO and PGO.
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Figure 4: Raman spectra of GO and PGO.

Mentions: Raman spectra (figure 4) show the peak positions and the ratio between the peak intensity of D band and that of G band (D/G) for GO and PGO, which reflects the structural changes occurring during the chemical processing from GO to PGO. D band (at about 1355 cm−1) is a breathing model of κ-point phonons of A1g symmetry, G band (at about 1600 cm−1) is usually assigned to the E2g phonon of C sp2 atoms [37]. As in figure 4, the Raman spectrum of GO is similar to that of PGO, suggesting that the skeletal structure of GO remains in the PGO after functionalization. However, there is a slight decrease of the D/G intensity ratio after functionalization, the decrease of the ratio indicates an increase of topological disorder in the graphene layer and a decrease in size of nanocrystalline graphene.


Novel PEPA-functionalized graphene oxide for fire safety enhancement of polypropylene
Raman spectra of GO and PGO.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Figure 4: Raman spectra of GO and PGO.
Mentions: Raman spectra (figure 4) show the peak positions and the ratio between the peak intensity of D band and that of G band (D/G) for GO and PGO, which reflects the structural changes occurring during the chemical processing from GO to PGO. D band (at about 1355 cm−1) is a breathing model of κ-point phonons of A1g symmetry, G band (at about 1600 cm−1) is usually assigned to the E2g phonon of C sp2 atoms [37]. As in figure 4, the Raman spectrum of GO is similar to that of PGO, suggesting that the skeletal structure of GO remains in the PGO after functionalization. However, there is a slight decrease of the D/G intensity ratio after functionalization, the decrease of the ratio indicates an increase of topological disorder in the graphene layer and a decrease in size of nanocrystalline graphene.

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.