Surface-modified aramid fiber and preparation method therefor

A method for preparing a surface-modified aramid fiber, comprising the following steps:

• (1) immersing a surface-cleaned aramid fiber in an alkali metal hydroxide alcohol solution having a mass concentration of 5.0 to 15.0%, and shaking and reacting at 65° C. for 5 hours to obtain an aramid fiber grafted with amino and carboxyl groups on a surface thereof;
• (2) immersing the aramid fiber grafted with amino and carboxyl groups in an organic solvent containing γ-glycidoxypropyltrimethoxysilane under an inert gas atmosphere, and reacting at 70° C. for 12 hours to obtain a silicon methoxylated aramid fiber;
• (3) dissolving a cerium salt and an inorganic base in water, stirring for 35 minutes, adding hydrogen peroxide to obtain a suspension, adjusting a pH of the suspension to 12, reacting at 40° C. for 12 hours, washing and filtering, drying, calcining at 700° C. for 2 hours to obtain a nano-cerium oxide;
• dispersing the nano-cerium oxide, a boron source and a nitrogen-containing compound in a mixed solution of ethanol and water, ultrasonically stirring for 1 hour, steaming and drying, calcining at 950° C. for 5 hours under a nitrogen source gas to obtain cerium oxide particles coated with boron nitride;
• (4) adding the cerium oxide particles coated with boron nitride and dopamine hydrochloride to a buffer having a pH of 8.5, and stirring at room temperature for 6 hours;
• filtering, washing, and drying to obtain a cerium oxide coated with polydopamine modified boron nitride;
• (5) immersing the silicon methoxylated aramid fiber in an aqueous solution of the cerium oxide coated with polydopamine modified boron nitride, and shaking at 60° C. for 6 hours;
• washing and drying to obtain the surface modified aramid fiber,
• wherein the aramid fiber is a para-aramid fiber or a meta-aramid fiber;
• the alkali metal hydroxide is sodium hydroxide;
• the inorganic base is sodium hydroxide;
• the inert gas is nitrogen gas;
• the organic solvent is ethanol;
• the cerium salt is cerium chloride;
• the boron source is boric acid;
• the nitrogen-containing compound is urea;
• the nitrogen source gas is nitrogen;
• and the buffer is Tris-HCl.