Synthesis of nano-SiO_2/polyacrylate composite emulsion and its film performance

A nano-SiO2/polyacrylate composite emulsion with high silica content was synthesized through in-situ polymerization of acrylate monomers with modified silica gel using the methods of monomers pre-emulsification and semi-continuous addition. The effects of the dosages of nano-SiO2 and methacrylic acid (MAA), composition of emulsifier, and solid content of emulsion on emulsion properties were studied. The structure and thermal stability of emulsion were characterized by infrared spectroscopy and thermogravimetry, and the performances of emulsion film was tested. A nano-SiO2/polyacrylate composite emulsion with good thermal stability was prepared with 20% SiO2 and 5% MAA (as functional monomer) using an emulsifier composed of 1:3 (mass ratio) OP-10 and DNS-86 at a solid content of 40%. The emulsion film has the following properties:pencil hardness 6H, adhesion strength 1 grade, wear resistance 2 500 r, and good resistance to water and heat.