Limits...
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.


The SEM images of GO (a), PGO (b), (c) and TEM images of GO (d), PGO (e), (f).
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Figure 5: The SEM images of GO (a), PGO (b), (c) and TEM images of GO (d), PGO (e), (f).

Mentions: SEM and TEM images are used to reveal the surface and structure morphology of GO and PGO at the submicrometer scale in figure 5. The SEM and TEM images of GO display that GO sheets exhibit a typically flat yet wrinkled nano-platelet shape within several ten-of-microns size (figures 5(a) and (d)) after an appropriate ultrasonic treatment. After surface functionalization, the ordered flat structure was broken into many disordered small pieces within several microns size (figures 5(b) and (c)), and there are many small dots wrap around the cracked GO sheets, as shown in figures 5(c), (e) and (f). These evidences demonstrate that the chemical reaction of the organics and –OH on the GO sheets could fracture the sheets due to the large size organic bounds planted into the narrow space of the layers. The strong inter- and intra-molecular interactions [38] make GO crushed and reassembled. During these processes the PEPA dots grow on the GO sheets and assemble into the structure as shown in figure 5(c). The PEPA, a kind of flame retardant additive, that cladding on the GO sheets is expected to form a protect layer on fire, which avoids the GO from burning out.


Novel PEPA-functionalized graphene oxide for fire safety enhancement of polypropylene
The SEM images of GO (a), PGO (b), (c) and TEM images of GO (d), PGO (e), (f).
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Figure 5: The SEM images of GO (a), PGO (b), (c) and TEM images of GO (d), PGO (e), (f).
Mentions: SEM and TEM images are used to reveal the surface and structure morphology of GO and PGO at the submicrometer scale in figure 5. The SEM and TEM images of GO display that GO sheets exhibit a typically flat yet wrinkled nano-platelet shape within several ten-of-microns size (figures 5(a) and (d)) after an appropriate ultrasonic treatment. After surface functionalization, the ordered flat structure was broken into many disordered small pieces within several microns size (figures 5(b) and (c)), and there are many small dots wrap around the cracked GO sheets, as shown in figures 5(c), (e) and (f). These evidences demonstrate that the chemical reaction of the organics and –OH on the GO sheets could fracture the sheets due to the large size organic bounds planted into the narrow space of the layers. The strong inter- and intra-molecular interactions [38] make GO crushed and reassembled. During these processes the PEPA dots grow on the GO sheets and assemble into the structure as shown in figure 5(c). The PEPA, a kind of flame retardant additive, that cladding on the GO sheets is expected to form a protect layer on fire, which avoids the GO from burning out.

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.