Covalent assembly of MCM-41 nanospheres on graphene oxide for improving fire retardancy and mechanical property of epoxy resin

In the study, the hierarchical nanohybrid (GO@MCM-41) with mesoporous MCM-41 nanospheres covalent assembling on graphene oxide (GO) nanosheets was successfully prepared, aiming to improve fire retardancy of epoxy resin (EP). Fourier transformation infrared spectra (FTIR), Raman spectra, X-ray diffraction (XRD), X-ray photoelectron spectra (XPS), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) verified GO@MCM-41. The nano-dispersion of GO@MCM-41 in EP was certified via TEM and XRD. Fire-retardant investigation (cone calorimeter test) revealed that EP nanocomposite with 2 wt% GO@MCM-41 possessed a 40.0% drop of peak heat release rate (pHRR) and suppressed smoke production relative to EP/GO. Intriguingly, EP/GO@MCM-41 demonstrated lower pHRR than EP/GO-MCM-41 (direct addition of GO and MCM-41). TG analysis indicated GO@MCM-41 imparted EP with significantly reduced degradation rate and increased char yield, accompanied by reduced volatile in thermogravimetric analysis couple with Fourier transformation infrared spectra (TG-FTIR) and improved aromatization in variable-temperature FTIR. The impact strength of EP/GO@MCM-41 was enhanced by 38.8% compared with EP. Contrastive analysis proposed the mechanism of neighboring synergy of GO and MCM-41, which involved in GO nanosheets wrapped by enormous carbonaceous stuffs due to MCM-41 neighboring catalysis. In perspective, hierarchical nano-assembly with neighboring synergy offered a viable approach for fire-safe polymers.