Three high-performance polyimides were exposed at 177°C to ultraviolet radiation at three different intensities and for three different times so that the product of intensity and time was a constant. Intensities of 1, 2 and 3 suns, and times of 500, 250 and 167h were used. One sun is the power in space at one earth-sun distance and is 0.135 J s -1 cm -2 . The polyimides were LARC™-8515, PETI-5 and K3B. Samples were analysed by XPS, TGA, TMA and DMA. Thermal analyses by TGA, TMA and DMA, which measure bulk properties, showed essentially no difference between samples exposed to heat and UV radiation, and control samples. Surface analysis by XPS showed an apparent decrease in carbonyl on the surface of some exposed samples. This could be correlated for the PETI-5 and LARC™-8515 samples to surface contamination by a silicone-containing material. © 1999 Society of Chemical Industry.
|State||Published - Oct 1 1999|