Characterization of Creep Behavior of Polymer Composites by the Use of Dynamic Test Methods

This paper describes a new dynamic test method for estimating momentary creep response of polymers and their composites. It is based on impulsive excitation of test specimens and the subsequent measurement of their frequency response functions. The vibration test involves the determination of frequency dependent storage modulus and loss factors. The Time-Temperature Superposition (TTS) principle is applied to the frequency domain vibration test data to form a master curve, which is then transformed to the time domain to generate the creep compliance master curve. In order to assess the validity of the new method, the static creep behavior for several materials was measured, and subsequently compared with creep results calculated from data obtained by the new dynamic test method. The materials studied are polyetherimide (PEI) neat resin and a unidirectional E-glass/PEI composite in the [90]12 (transverse) configuration.