Method for preparing nano silicon dioxide/aqueous polyurethane hybrid material

The invention discloses a method for preparing a silicon dioxide/aqueous polyurethane hybrid material, which comprises: preparing an isocyanate terminated polyurethane prepolymer by reacting a polyisocyanate and a polyol in the presence of a carboxyl hydrophilic chain extender and a small molecular chain extender; adding an amino or hydroxyl silane coupling agent to react the amino or hydroxyl silane coupling agent with the polyurethane prepolymer to obtain siloxane terminated polyurethane; and adding neutralizing agent to form a salt, adding a precursor and deionized water for emulsion, and obtaining the silicon dioxide/aqueous polyurethane hybrid material with a solid content of 10 to 80 weight percent. The hybrid material has better stability at room temperature, avoids discharge of volatile organic compound (VOC) during film forming and has the advantages of environment protection and the like. In addition, besides good mechanical properties, the film made of the hybrid material has excellent water resistance, solvent resistance, thermal stability and the like. The material is widely used in fields of pain and coating.