A new elongational rheometer for polymer solutions

Design and operation of a new elongational rheometer for low elastic polymer solutions are described. The free jet elongational rheometer is easy to operate and for suitable operating conditions a transient elongational flow with an approximately constant rate of strain can be realized. In any case, convenient comparative parameters can be obtained. The method of rheological curve fitting leads to a deformation dependent ralaxation time parameter of a modified upper convected Jeffreys-law.