The effects of applied strain on sealants exposed to outdoor weathering were examined for two sealant formulations, sealants A and C. Both static and dynamic strain was applied to the sealants during the summer in a Gaithersburg, MD-outdoor location. Both sealants exhibited a reversible change in equilibrium distance. Stress relaxation studies on all samples revealed that, for sealant A, two mechanisms affected modulus change; exposure without applied strain increased the modulus while additionally applied strain decreased the modulus. Only one mechanism that decreased the modulus was found for sealant C. A 7% dynamic strain and a 25% static strain were observed to produce equivalent modulus changes in both systems.
Citation: Journal of ASTM International
Pub Type: Journals
Sealant, Strain, Modulus, Outdoor Weathering, Characterization