Weathering modification of acrylic emulsion by introducing UV absorbing groups

Abstract

A new kind of UV‐absorbing silicon‐fluorinated acrylic emulsion was prepared by emulsion polymerization with 4‐allyloxy‐2‐hydroxybenzophenone, 3‐methacryloxypropyltrimethoxysilane (MPS) and hexafluorobutyl methacrylate (HFMA) as functional monomers. The emulsion and its coating were characterized by transmission electron microscope, Fourier transform infrared spectrum (FTIR), X‐ray photoelectron spectroscopy, ultraviolet absorption spectrum，thermo‐gravimetric analysis, water contact angle (CA), and artificial accelerated aging test. The results indicated that the emulsion with core‐shell structure was synthesized and showed prominent absorption peaks at 320 and 350 nm. The water CA of the coating was increased from 70.2° to 86.7° because of the incorporated HFMAs and MPSs. Both of the initial and final decomposition temperatures of the coating were increased by more than 20°C compared with those of the unmodified coating. After 10 days of accelerated aging, the color difference (ΔE) and rate of loss of gloss (ΔG) were only 2.78% and 5.22%, while those of the unmodified coating were as high as 22.94% and 78.57%, respectively. Because of the UV absorbers were incorporated by chemical reaction, the new coating had a more durable and effective anti‐ultraviolet performance compared with the coatings the UV absorbers were introduced by physical blending.