Simultaneous reduction and surface functionalization of graphene oxide with POSS for reducing fire hazards in epoxy composites

Abstract

Simultaneous reduction and surface functionalization of graphene oxide (GO) was realized by simple refluxing of GO with octa-aminophenyl polyhedral oligomeric silsesquioxanes (OapPOSS) without the use of any reducing agents. The presence of OapPOSS made the hydrophilic GO hydrophobic, evidenced by the good dispersion of the OapPOSS-reduced GO (OapPOSS-rGO) in tetrahydrofuran solvent. The structure of OapPOSS-rGO was confirmed by XPS, FTIR and TEM. Morphologic study showed that, due to the good interfacial interaction between the functionalized graphene and epoxy, OapPOSS-rGO was dispersed well in the matrix. With the incorporation of 2.0 wt% of OapPOSS-rGO, the onset thermal degradation temperature of epoxy composite was significantly increased by 43 o C. Moreover, the peak heat release rate, total heat release and CO production rate values of OapPOSS-rGO/EP were significantly reduced by 49%, 37% and 58%, respectively, 2 compared to that of neat epoxy. This dramatically reduced the fire hazards were mainly attributed to the synergestic effect of OapPOSS-rGO: the adsorption and barrier effect of reduced graphene oxide inhibited the heat and gas release and promoted the formation of graphitized carbons, while OapPOSS improved the thermal oxidative resistance of the char layer.

Fabrication of Ce-doped MnO2decorated graphene sheets for fire safety applications of epoxy composites: flame retardancy, smoke suppression and mechanism

“…The continuous and compact char surfaces are good barriers to protect the underlying polymers and inhibit the exchange of degradation products, combustible gases and oxygen. 48,49 The results of flammability exhibit that CeMnO2-GNS-EP nanocomposite show the best flame retardancy among EP nanocomposites. By combining TGA and cone calorimetry results, it is reasonably believed that some epoxy chains participated in the carbonization process due to the barrier effect of GNS and the catalysis of Ce-MnO2, and more and better chars are formed, which decrease the flammability of EP nanocomposites.…”

“…The dense char layer can lower the efficiency of heat and volatiles transference because of the strong hindering effect, and can provide better flame shielding for the underlying material during combustion. 48,49 The char residue of Ce-MnO2-GNS-EP was also characterized by its XRD pattern, as shown in Fig. 12E.…”

Graphene-based flame retardants: a review

“…Small organic molecules, such as organosilicon compounds [64][65][66][67][68], cetyltrimethyl ammonium bromide [69] and pentaerythritol [70], are modified or adsorbed onto the planes and edges of graphene sheets to create organic-small molecule graphene composites. The incorporated small organic molecules act as a bridge between graphene and polymer matrices and form a network structure, thereby increasing the dispersion of graphene and improving the mechanical properties of the composites.…”

Flame retardancy and mechanical properties of ferrum ammonium phosphate–halloysite/epoxy polymer nanocomposites

“…The DTG curve showed a minimum (20.10%/ C) at 141 C, probably as a consequence of the NH 4 FePO 4 ÁH 2 O nanoplate thermal decomposition. 27 The results indicate the process of the loss of water and ammonia.…”