The Waterborne Symposium

Abstract: Applications of Dynamic Mechanical Analysis to Characterize Coating Performance

Dynamic Mechanical Analysis (DMA) is an underutilized capability in characterizing coatings.  The performance of a coating is more often evaluated by directly applying destructive deformation such as abrasion, scratch, delamination, and elongation-at-break.  These tests are valuable in differentiating performance, but they can show significant variability and do not provide insight into the relationship between chemical composition and end-use properties.
The viscoelastic mechanical properties of a coating are highly relevant to attributes such as flexibility, adhesion, and abrasion and scratch resistance.  This can be dependent on the glass transition of the formulation components, but characterizing this is often neglected if the operating temperature of the final coating is not a concern.  Routine testing of glass transition behavior by DMA can be valuable in understanding the effects of changes in formulation on final properties, and on the chemical compatibility of the components.
This work will present DMA measurements of commercial coatings to demonstrate a relationship between viscoelastic behavior and physical properties.  Testing will include both linear and non-linear viscoelastic properties, and the effects of environmental conditions such as humidity and submersion.  Testing will primarily focus on free films of coatings, but will also demonstrate the ability to measure coatings permanently bonded to a substrate for applications where generating free films is not experimentally feasible.