The functionalization of carbon nanofibers with 4,4′-diaminodiphenylmethane, a curing agent for epoxy resins

A. functionalization technique for carbon nanofibers (CNFs) via acid is described. The integrity and chemical nature of the CNFs during the different stages of the applied treatment (oxidation, activation, and functionalization) were examined using different microscopic, chemical, and thermal analysis techniques. The treatment effect on the dispersion ability of the nanofibers in different solvents (tetrahydrofuran, chloroform, and acetone) was also evaluated. Results show that chloroform is the best medium to reach good dispersions and stability of the CNFs in a wide range of concentrations. Using this medium, the functionalization process using 4,4'-diaminodiphenylmethane (DDM) was adopted for the fabrication of reactive CNFs with linker molecules on their surface capable of binding covatently to thermosetting polymers, such as epoxy. The DDM surface derivatized CNFs have been used as reinforcement in epoxy matrix nanocomposites with improved thermomechanical properties in relation to non-treated carbon nanofibers.