Method for preparing polyacrylonitrile-based double-layer carboxyl fiber through reduction method

The invention belongs to the technical field of functional polymer materials, and particularly relates to a method for preparing polyacrylonitrile-based double-layer carboxyl fibers through a reduction method. The preparation method comprises the following steps: 1) partially reducing nitrile groups in low-molecular-weight polyacrylonitrile powder into amino groups to obtain partially aminated polyacrylonitrile; 2) grafting the partially aminated polyacrylonitrile fiber onto a carboxylated polyacrylonitrile fiber to obtain a polyacrylonitrile fiber with a double-layer structure; and 3) hydrolyzing the polyacrylonitrile fiber with the double-layer structure under an alkaline condition to obtain the polyacrylonitrile fiber with the double-layer structure. The prepared double-layer carboxyl fiber is better in mechanical property, higher in carboxyl content and utilization rate, has the advantages of being large in exchange capacity, high in adsorption-desorption rate and diversified in application form in the us