Effect of heat treatment on carbon fiber surface properties and fibers/epoxy interfacial adhesion

► The carbon fiber surface properties and fiber/epoxy interfacial adhesion have great changes during heat treatment. ► This research has concluded that the wettability depends not only by the surface energy values of carbon fiber and resin, but also on the polarity match of surface energy. ► Close correlation can be found between IFSS and the concentration of reactive groups in interface region including hydroxyl group and epoxy group. ► The results can be theoretical guidance for improving performances of carbon fiber and carbon fiber reinforced resin matrix composite.