Coating Mechanics to Defend Against the Environmental Elements

By Nicholas Foley, Xin Li, Jack Johnson

Exterior surfaces experience degradative environmental conditions, such as intense UV exposure, rain, and temperature swings, leading to deterioration. Coatings are low-cost solutions offering decades of protection and preventing significant repair costs for buildings. The coating must withstand UV, mitigate water damage, and express the flexibility required to maintain adhesion to dimensionally unstable substrates (i.e., wood) as they undergo thermal expansion and contraction through the days and seasons.

BASF has investigated paint film mechanics through accelerated thermal cycling grain crack and tensile testing with intent to correlate the film properties to exterior exposure data. In this article, we demonstrate that adhesion after accelerated weathering, combined with tensile elongation testing, can be used to model outdoor weathering.