Using colorimetric methods to analyze the impact of acrylic binders' physical-chemical factors on dirt-pickup resistance of white façade coatings

Abstract

Building façade is one of the most significant factors to make the city glamorous; for this reason, special attention should be paid to the cleanness of buildings' exterior surface from pollution. This work intends to study the effect of physical-chemical parameters of acrylic façade coatings on its dirt-pickup resistance. Five pigmented white coatings based on five acrylic resins, and the corresponding clear coatings were prepared. Then, using dirt simulating past, half of the pigmented- and clear-coatings was contaminated. After cleaning the contaminated area, the dirt-pickup resistance of both clear and pigmented coatings was investigated through colorimetric methods. FTIR and DSC were used to analyze the physical and chemical properties of the acrylic resins. Besides, contact angle and water uptake were measured. Finally, the correlations between the physical-chemical parameters of acrylic binders and their colorimetric attributes were studied. Results showed that the higher glass transition temperature, lower water uptake, lower δ C-OH/ν CH ratio, and higher water droplet contact angle results in a better dirt-pickup resistance.