1.1.13.2.4 Elastomeric Adhesives

1.1.13.2.4 Elastomeric Adhesives

Elastomeric adhesives possess unique rheological characteristics and have their own classification. The synthetic or naturally occurring elastomeric polymers on which they are based allow them to withstand considerable compression or elongation before suffering plastic (permanent) deformation. While materials, when unloaded, will return to their original dimensions if they have not been deformed beyond their yield point, elastomeric polymers and adhesives can be deformed considerably – sometimes several times their initial length – before this point is reached. Compare this to a rigid epoxy’s single-digit percent elongation before yield. Elastomeric adhesives excel in energy absorption and are commonly used for sealing, vibration damping and soundproofing. Their flexibility and low modulus make them robust in joint designs requiring resistance to peel and cleavage forces, non-uniform loading, flexure and thermal expansion differentials.

The same low modulus and high elongation that makes them so valuable in situations requiring flexibility render elastomeric adhesives less desirable for structural bonding, which requires high rigidity and load-bearing properties. Crosslinked thermosetting elastomeric adhesives may be considered for structural joints, but these applications must be carefully vetted for the reasons outlined above.