Viscoelasticity and Pressure Sensitive Adhesive
No pun intended, but it is hard to separate the relationship between viscoelasticity and pressure sensitive adhesive (PSA). What exactly is viscoelasticity and why is it important in a PSA? Let's try to take a potentially complex issue and break it down.
What is Viscoelasticity?
Viscoelasticity is a blend of the words viscosity and elasticity.
- Viscosity refers to the resistance a liquid has to flow, generally related to the thickness of the liquid.
- Elasticity is the ability for a solid to return to its original shape once strain is removed.
Examples of elastic materials include viscoelastic foam, rubber bands, stress balls and bungee cords. High viscous materials are generally thick liquids or gels. Honey, motor oil, and syrups are considered high viscosity liquids. Low viscosity liquids flow easily, like water.
The Affect of Heat on Viscosity
Heat reduces viscosity which you can see in daily life. Oil loses viscosity as it heats in an engine. Maple syrup will flow easier when warmed. Gels will even lose their form when subjected to heat. This is an important fact to keep in mind when discussing the relationship between viscoelasticity and PSA. Heat has an effect on both.