Hydrophilic modified flexible self-crosslinking fiber as well as modification method and application thereof

The invention discloses a hydrophilic modified flexible self-crosslinking fiber and a modification method and application thereof. The length of the modified flexible self-crosslinking fiber is 200-12000mu m, the diameter of the modified flexible self-crosslinking fiber is 3-120mu m, the crystallinity of the modified flexible self-crosslinking fiber is 40-90%, and the surface of the modified flexible self-crosslinking fiber is provided with one or more hydrophilic groups of hydroxyl, amino, imino, carboxyl and sulfo. The modification method adopts a chemical method, a physical method or a plasma method; the fiber has a good application prospect in unconventional reservoir fracturing; by utilizing the fiber, the sand-carrying performance of the low-viscosity fracturing fluid can be improved. The fiber is good in temperature resistance stability and shows good flexibility, a stable self-crosslinking network structure is formed in the fracturing fluid, the fracturing fluid prepared from the fiber can improve the