Thermal degradation of polyetherimide joined by friction riveting (FricRiveting). Part I: Influence of rotation speed

The thermal degradation of polyetherimides joined by friction riveting (FricRiveting) (Amancio Filho ST, Beyer M, Dos Santos JF. Verfahren zum Verbinden eines metallischen Bolzens mit einem Kunststoff-Werkstück - DE 10 2005 056 606 A1. Germany: Deutsches Patent- und Markenamt; 2007) has been investigated for varying rotation speeds. The rotation speed is an important variable to be understood in order to predict thermal degradation during this process. Investigated rotation speeds in the range of 1570-2199 rad/s resulted in high process temperatures (350-475 °C) and heating rates (up to 2 °C/100 rad/s), but only small heating times (<3 s). Thermal degradation was evaluated by gel permeation chromatography, Fourier transform infrared spectroscopy and X-ray computer microtomography. The results indicated that thermal degradation in the PEI polymer was mainly due to chain scission. Moreover, the small level of thermally degraded material (average drops of 10% in molecular weight) showed only a minor dependence on rotation speed. Although high peak temperatures and heating rates were present, the restricted variation and average values of heating time were insufficient to cause strong thermal changes in the joints of the studied rotation speed range.