Secondary Relaxations in Polymers Containing Phenyl Rings
The dynamic mechanical behaviour of bisphenol-A-polycarbonat (PC), polyarylsulfon (PES), polyetherimid (PEI), polyamidimid (PAI) and polyaryletheretherketon (PEEK) has been investigated in the temperature range between -170 and +270 °C and generally two decades around 1 Hz on the frequency axis. Although there are great differences in the chemical structure in regard of their repeating units, all polymers investigated show a maximum in mechanical damping between -100 and -90 °C at an interpolated frequency of 1 Hz. Significant differences in the damping behaviour were found at higher temperatures. While PC, PEEK and PES have shoulders in the neighborhood of 0 °C and a broad minimum around +100 °C, both polyimids are characterised by wide maxima from -20 °C up to their glass rubber transition.
KeywordsPhenyl Ring Aromatic Polymer Tetracarboxylic Acid Secondary Relaxation Dynamic Mechanical Behaviour
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