| Abstract: | Viscoelastic parameters for poly(ethylene terephthalate) (PET) fibers heat set under different conditions were determined at 110 Hz between room temperature and about 200°C. The correlation of dynamic mechanical properties with structure and their dependence on the temperature of the measurement are discussed. It was found that in addition to the structural parameters such as degree of crystallinity, crystallite and amorphous orientation, etc., morphological factors such as size and distribution of crystallites also influence the dynamic mechanical properties. The activation energy of the α-transition is reported, and the effect of the distribution of relaxation times on the activation energy is discussed. |
