Available at: https://digitalcommons.calpoly.edu/theses/3289
Date of Award
6-2026
Degree Name
MS in Polymers and Coatings
Department/Program
Chemistry & Biochemistry
College
College of Science and Mathematics
Advisor
Erik Sapper
Advisor Department
Chemistry & Biochemistry
Advisor College
College of Science and Mathematics
Abstract
Solar reflective coatings offer a promising strategy to mitigate the urban heat island effect by reducing absorption of near-infrared solar energy. This thesis project investigates the feasibility of incorporating near-infrared reflective pigments into waterborne direct-to-metal (DTM) latex coating systems while maintaining acceptable color comparison characteristics and coating performance. An all acrylic latex DTM formulation with titanium dioxide as the sole pigment was prepared and tinted with a variety of conventional and solar reflective commercial colorants across the yellow, red, blue, and green color ranges. Coatings were evaluated for solar reflectance, CIELAB color, gloss, contrast ratio, rheological behavior, accelerated ultraviolet weathering resistance, and salt fog spray corrosion resistance. Comparisons between conventional and solar reflective pigments demonstrated that performance improvements were highly dependent on pigment chemistry and color family. Chrome antimony titanium buff rutile and yellow iron oxide solar reflective pigments provided measurable increases in solar reflectance while maintaining comparatively low color deviation from conventional references, while other colors demonstrated only minimal reflectance improvements or poor color matches. The titanium dioxide-rich white base was found to strongly influence overall reflectance behavior, limiting the observable gains achievable with many pigment substitutions. Accelerated weathering and corrosion testing additionally showed that pigment selection influenced long-term coating durability and appearance retention. Overall, this work demonstrates the practical potential of selected solar reflective pigments in DTM coating systems while highlighting the challenges associated with balancing color accuracy, solar reflectance, wet coating behavior, and long-term durability in real-world coating applications.