SUMMARY
This work aims to clarify the difference between the influence of TiO2 particles at micrometer and nanometer sizes on the mechanical properties and weathering durability of water-based acrylic coatings. To prepare coatings, micro-R-TiO2 and nano R-TiO2 particles with 2 wt.% content were dispersed in the emulsion acrylic polymer by ultrasonic vibration. The coatings without TiO2 particles, with 2 wt.% micro R-TiO2 and with 2 wt.% nano R-TiO2 were tested for abrasion resistance, weathering aging in UV/CON accelerated weathering chamber. Weathering aging was assessed by IR quantitative analysis, the weight loss of the coating. The obtained results showed that the micro R-TiO2 with the 2 wt.% content enhanced simultaneously the abrasion resistance and weathering durability of water-based acrylic coatings but not as effectively as nano R-TiO2. Incorporation of 2 wt.% micro-R-TiO2 increased slightly the abrasion resistance of coating from 78.4 to 98.9 lite/mil (26% increase) while with addition of nano-R-TiO2 at the same content, the abration resistance was significantly improved from 78.4 to 129.3 lite/mil (65% increase). After 48 aging cycles, the alkane CH groups and weight of the coatings without R-TiO2 particles, containing 2 wt.% micro-R-TiO2, containing nano-R-TiO2 lost 34.2% and 17.4%; 23.8% and 13%; 13.7% and 13 %, respectively.