Preparation method for surface-modified polyacrylic acid microspheres

The invention relates to a surface modification method for powder, in particular to a surface modification method for polyacrylic acid microspheres and a polysulfide sealant containing surface-modified polyacrylic acid microspheres. According to the method, surface treatment is performed on the polyacrylic acid microspheres by adopting a two-step method with hydroxyl-terminated unsaturated monomers and thioether monomers, grafting modification is performed on the surfaces of the polyacrylic acid microspheres to enable the thioether structures to be evenly and stably distributed on the surfaces of the microspheres, therefore, the dispersity of the microspheres in liquid polysulfide rubber is effectively improved, and the viscosity of base adhesives is reduced; meanwhile, in the base adhesive sulfidation process, the thioether structures on the surfaces of the microspheres also have reactive active groups to participate in a sulfuration reaction, therefore, stable chemical bonds are formed between the microspheres and a matrix, connection between the microspheres and the matrix is enhanced, and then the mechanical properties of macroscopic materials are enhanced. In addition, according to the modification method, the needed technology conditions are easy to achieve, the product property is stable, and large-scale production of products is facilitated.