Abstract
This study aimed to prepare ecofriendly flame retardants. Using the –OH and –COOH functional groups of multilayer graphene oxide (GO) for the hydrolytic condensation of tetraethoxysilane (TEOS), TEOS was grafted onto GO to form Si-GO. Subsequently, p-aminophenol (AP) was grafted onto Si-GO to produce Si-GA, forming composite materials with epoxy (EP). The structures and properties of the composite materials were examined with Fourier-transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), and the limiting oxygen index (LOI). In terms of structure, FTIR observed two characteristic peaks of Si-GO, namely Si–O–C and Si-O-Si, indicating that TEOS was successfully grafted onto GO. TGA was used to determine the thermal stability of the epoxy/Si-GA composites; with the increase in Si-GA, the char yield of the materials increased from 15.6 wt % (pure epoxy) to 25 wt % (epoxy/10 wt % Si-GA), indicating that Si-GA effectively enhanced the thermal stability of the epoxy matrix. Lastly, the flame retardant tests determined that the LOI value rose from 19% (pure epoxy) to 26% (epoxy/10 wt % Si-GA), proving that graphene with modified silicon can be used to enhance the flame retardancy of epoxy.
Highlights
Polymer materials have a wide range of applications
Fourier-transform infrared spectroscopy (FTIR) and X-ray photoelectron spectra (XPS) analyses proved that TEOS was grafted onto graphene oxide (GO)
The integrated procedure decomposition temperature (IPDT) values increased with the concentration of Si-GA, which increased from 629 ◦C for pure epoxy to 825 ◦C for 10 wt % of epoxy/Si-GA; this was a 196 ◦C increase
Summary
Polymer materials have a wide range of applications. their popularity has necessitated the development of their flame resistance, either by increasing the flame retardancy of a material itself, or through the addition of flame retardants. Epoxies are high performance materials with excellent mechanical and chemical properties, they are highly combustible. This has actuated the demand for flame-proof epoxy, of which the most widely researched are epoxies that are both incombustible and halogen-free in accordance with the WEEE (Waste Electrical and Electronic Equipment) and RoHS (Restriction of Hazardous Substances) directives [3,4,5]. The demands for halogen-free flame retardants, coupled with the used of nanotechnologies, will indirectly lead to improvements in material incombustibility [6,7] This indicates the immense business opportunities behind such successful research, which has triggered fierce competition worldwide regarding related research
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