Determination of internal friction of polymer solids with the pulse propagation technique

Abstract

The pulse propagation technique has been useful to determine the dynamic Young's modulus of a wide range of materials. However, the applicability of the sonic technique to internal friction measurements on solids has not been exploited fully. In this report the theoretical and experimental studies on determination of internal friction of solids with the pulse propagation method are described. New instrumentation and a procedure for internal friction measurements are discussed. The internal frictions are determined for the experimental polymer solids. Polyimid (PI), polyetherimide (Ultem), polyethersulfone (PES) and polyphenylene oxide show lower internal friction which indicates that polymers have stiff chain molecules in the structure and show high glass transition temperatures. This method will be useful for non-destructive measurement of internal friction and opening new areas of application. © 1985, The Society of Fiber Science and Technology, Japan. All rights reserved.