Effect of tri(methoxysilyl)propyl methacrylate silane modified nanosilica on some properties of acrylic coating

Abstract

Acrylic emulsion resin is one of popular matrixes for both outside and inside coatings. It has low cost, high UV and weather resistance, good aesthetics and environmentally friendly. The introduction of inorganic additives in nanosize such as SiO2, TiO2, etc. into acrylic emulsion resin could improve the mechanical and thermal properties of the polymer matrix. The surface modification of nanoparticles can enhance the dispersibility of the nanoparticles in the polymer matrix. This paper presents the characteristics of nanosilica modified with different contents of tri(methoxysilyl)propyl methacrylate silane (MPTS) as a coupling agent and the effect of modified nanosilica on the abrasion resistance and thermal properties of acrylic emulsion resin. The infrared (IR) spectroscopy and thermo-gravimetric analysis (TGA) were used to evaluate the presence of MPTS on the surface of modified nanosilica. Grafting yield of MPTS on the surface of nanosilica was calculated from TGA diagrams. The obtained results showed that nanosilica was surface modified successfully by MPTS with a grafting yield of 47 % when using 3 wt.% of MPTS. After modification, the modified nanosilica became more hydrophobic and can disperse well in acrylic emulsion resin. The modified nanosilica improved significantly the abrasion resistance of acrylic coating as compared to neat acrylic resin and acrylic/unmodified silica nanocoating. The MPTS modified nanosilica has the potential to be applied as a reinforcing additive to acrylic emulsion resins to improve its abrasion resistance.