Gel-sol synthesis of surface-treated TiO_2 nanoparticles and incorporation with waterborne acrylic resin systems for clear UV protective coatings

摘要

Visible transparent UV protective coatings were developed by incorporating nano-TiO_2 into waterborne acrylic systems to provide UV protection for UV-sensitive color cool roofing. Water-based high crystalline TiO_2 nanoparticle suspension was prepared via a gel-sol method at a basic pH. The TiO_2 nanoparticles have an average size of 20 nm and are stable against agglomeration. As-prepared TiO_2 nano-suspension is ready to be well dispersed in commercial waterborne acrylic resin system without extra-surface modification. The fabricated TiO_2/acrylic nanocom-posite coating achieved a UV cut-off below 350 nm with a visible transmission greater than 85% at 700 nm. It is also demonstrated by using Rhodamine 6G that surface modification of nano-TiO_2 with a SiO_2 insulation layer would suppress the catalytic activity of nano-TiO_2 and improve the UV protection for UV and photocatalysis sensitive dyes.