Adhesion of construction sealants to polymer foam backer rod used in building construction

Abstract

Sealants play a vital role in maintaining the weather tightness of modern high-rise buildings. Typical sealed joints comprise an elastomeric sealant, a backing foam and the sides of the joint corresponding to the cladding panels. Conceptually, the sealant should adhere only to the sides of the joint to enable maximum movement capacity of the material to be utilised; this is known as two-sided adhesion. Previous work has shown that the sealant sometimes adheres to the backing material, resulting in three-sided adhesion, and that this results in a decrease in joint performance. The adhesion between the foam and the sealant was studied using tack and peel tests, and the results were compared with measurements of the surface energies of the foams and the surface tensions of the sealants. Adhesion mechanisms are suggested and peel force–surface energy correlations are presented. Implications for the practical application of the results in building construction are made.