Preparation and characterization of colloidized diamine/oxidized-graphene via condensation polymerization of carboxyl groups epoxy/oxidized-graphene nanocomposite

A different sequence of epoxy composite preparation was performed by mixing oxidized graphene platelets (oGNP) with a curing agent prior to mixing it with epoxy resin. When oGNP was mixed with trimethylhexamethylene diamine (TMD), the condensation reaction between the hydroxyl and amine groups resulted in the formation of a TMD/oGNP colloid. The TMD/oGNP colloid was used to cure epoxy resin. The colloidization eventually improved the dispersion and prevented re-agglomeration in the epoxy resin. A thermogravimetric analysis showed that the thermal stability of the epoxy/oGNP system had improved, while the presence of the oGNP gave more stability to the solvent in terms of an increase in the crosslink density. These results showed that the TMD/oGNP colloid sequence was better able to enhance the properties of the epoxy composite compared to the conventional method of obtaining epoxy/graphene by mixing the graphene with the epoxy resin prior to adding in the curing agent. [Display omitted] •Overview of conventional methods for graphene filled epoxy nanocomposites fabrication manufacturing processes is presented.•New sequence of fabrication to maintain high dispersion of graphene in epoxy matrix with less re-agglomeration is reported.•Colloidal mixture of oxidized graphene and diamine curing agent is prepared prior to mixing with epoxy resin.•Colloidal polymerization between oxidized graphene and diamine curing agent is expected to stabilize the mixture.•Improved dispersion level of graphene and increased crosslink density enhances tensile and thermal properties.