sharkskin and spurt (i.e., stick-slip transition)

You are watching extrusion of a polymeric liquid from a capillary die of diameter around 1 mm. Similar process is applied to tens of billion pounds of polymeric materials every year. As the applied pressure increases, the so called sharkskin surface roughness increases until the sample undergoes spurt, which is a stick-slip transition.

A one-hour seminar is now available on the relevant subject of nonlinear rheology of entangled polymers:

http://youtu.be/ffbhZYlkWcA
Visit http://www3.uakron.edu/rheology/ for more information

Category:

Science & Technology

Tags:

• sharkskin
• polymer rheology
• extrusion