Incorporation of epoxy resin and graphene nanolayers into silica xerogel network: an insight into thermal improvement of resin

Three well-tuned procedures were used for thermal improvement of epoxy resin (E). Accordingly, graphene xerogel (GX) was used as nanofiller in the matrix of E. Additionally, (3-isocyanatopropyl)triethoxysilane-modified E (IE) or tetraethyl orthosilicate (TEOS) oligomer-modified E (TE) was incorporated into a hybrid structure of graphene-containing silica/siloxane network. For this purpose, a bifunctional silane coupling agent of 1,1'-(hexane-1,6-diyl)bis(3-(3-(trimethoxysilyl)propyl)urea) (HDBTMSPU) was synthesized. GX was obtained by incorporation of HDBTMSPU-modified graphene oxide (FGO) into xerogel structure using HDBTMSPU and TEOS. Modified resins, FGO, HDBTMSPU, and TEOS were also used in preparation of hybrid products. Thermal stability and char residue of the composites were compared. GO modification was approved by Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, Raman, X-ray diffraction, and thermogravimetric analysis results. Hybrid composite of IE, FGO, and silica/siloxane network shows higher thermal properties. Char residue is increased by 16.93 % by loading of only 1 wt% of FGO in this hybrid product.