Method for modifying surface of asphalt-based carbon fiber by using rigid-flexible polymer system

The invention discloses a method for modifying the surface of asphalt-based carbon fiber by using a rigid-flexible polymer system. The method comprises the following steps of: subjecting asphalt-basedcarbon fiber having undergone agent removal treatment to carboxylation, hydroxylation and amination successively with concentrated nitric acid, a saturated solution of lithium aluminum hydride/tetrahydrofuran and a silane coupling agent solution; and then grafting rigid polydopamine and flexible polyetheramine onto the surface of the asphalt-based carbon fiber by using an impregnation method so as to complete modification of the surface of the asphalt-based carbon fiber and form a modified coating of the rigid-flexible polymer system on the surface of the asphalt-based carbon fiber, wherein the modified coating is uniformly coated on the surface of the carbon fiber in a granular manner and can form a rigid-flexible hybrid cross-linked network structure in an interface area after compounding with resin, which is b