Preparing method for amino-terminated polyurethane for improving tenacity of cured epoxy material

The invention discloses a preparing method for amino-terminated polyurethane for improving tenacity of a cured epoxy material. The preparing method includes the following steps that 1, in the presence of a catalyst, polyether glycol and diisocyanate are polymerized in the nitrogen atmosphere; 2, the product is cooled to room temperature, and a viscosity modifier is added to obtain a prepolymer solution; 3, the temperature is kept at 2-10 DEG C, the product in the step 2 is added into an aliphatic polyamine solution, the mixture is heated to 40-50 DEG C, the temperature is kept for 1-3 h, and amino-terminated polyurethane for improving tenacity of the cured epoxy material is collected from a reaction product. The method is simple, polyamine terminal seal with primary amine and secondary amine is involved, the application range is wider, the polymerization success rate is up to 95%, the gel crosslinking phenomenon occurs rarely, the prepared amino-terminated polyurethane molecular chain is uniform and regular,