In situ cross-linking capability of novel amine-functionalized graphene with epoxy nanocomposites

In situ chemical linkage between nanofillers and polymer is challenging, but it is an effective process for enhancing the mechanical and thermal properties of polymer nanocomposites. Herein, novel amine-functionalized graphene is designed and developed to show the in situ chemical interaction with epoxy matrix. Three different graphene materials, graphene oxide (GO), carboxylic graphene oxide (GO-COOH), and ethylenediamine substituted graphene oxide (GO-CONHCH2CH2NH2) is synthesized chemically, and epoxy nanocomposite with different wt% is fabricated. FTIR showed the presence of hydroxyl and amide bond formation, confirmed by C-13-NMR, where the carboxylic carbon peak of GO at 193 ppm shifted to 184 ppm for GO-CONHCH2CH2NH2. Elemental analysis by XPS showed that C: O: N of GO changed from 70:30:0 to 79:13:8 for GO-CONHCH2CH2NH2. Three-point bending studies revealed that maximum flexural strength and modulus for GO-CONHCH2CH2NH2 incorporated epoxy polymer composite because of intermolecular chemical bond formation between the epoxy resin and GO-CONHCH2CH2NH2. The formation of a chemical bond between GO-CONHCH2CH2NH2 and epoxy polymer is confirmed by Raman spectroscopy and XPS analysis. The mechanism of forming an in situ chemical bond between amine-functionalized graphene and the epoxy polymer is derived based on experimental evidence.

Automated summary

In situ chemical linkage between amine-functionalized graphene and epoxy polymer has been successfully achieved, leading to improved mechanical and thermal properties of nanocomposites. The formation of a chemical bond between the graphene and epoxy is demonstrated and its mechanism is derived based on experimental evidence.