Chemorheology of reactive graphitic nanofiber-reinforced epoxy as a composite matrix

Abstract Based on the development of a series of nanofiber/epoxy matrices with reactive graphitic nanofibers (r-GNFs) in our previous work, the flow behavior and cure process of the nanofiber/epoxy materials with 0.1, 0.3 and 1.3 wt% of r-GNFs were investigated by rheological method and differential scanning caloremetry (DSC) tests. Non-isothermal and isothermal viscosity curves (at 110, 115 and 120°C, respectively) were obtained. The gel time was obtained from the isothermal tests for the neat epoxy resin and the nanofiber/epoxy systems. Nanofiber/epoxy matrix has longer gel time. Arrhenius activation energies obtained from both DSC and rheological tests showed close values for the nanofiber/epoxy matrices with different contents of r-GNFs. These results on the flow and curing characteristics of the nanofiber/epoxy matrices indicated that the nanofiber/epoxy matrices have good processability for manufacturing fiber composites and are expected to improve the properties of the fiber composites. Both isothermal and non-isothermal viscosity models were applied to describe the rheological behaviors of the nanofiber/epoxy matrices. On the one hand, a four-parameter isothermal model was found to be valid in simulating the isothermal process; on the other hand, a five-parameter non-isothermal model was constructed and found suitable for describing the non-isothermal behavior of the nanofiber/epoxy matrices. The theoretical results from the chemorheological models were found to be in good agreement with the experimental data. Keywords: CHEMORHEOLOGYGRAPHITIC NANOFIBERSNANOCOMPOSITESCHEMORHEOLOGICAL MODEL