Our current understanding regarding the evaluation of the thermal endurance and UV radiation stability of two different types of commercially available aromatic polyimides at elevated temperatures is presented. Such materials are typically used as thermal control foils. To characterise the thermal endurance we have performed a high vacuum thermal ageing campaign at 350 degree C up to 4452 hrs. During that test we found the mass loss to be higher for the K-film than for the U-film material. Further UV/VIS/NIR transmission and thermo-optical measurements revealed the degradation behaviour of both films versus time at 350 degree C. We found that in general the U-film degrades at a slower rate. To screen the radiation stability we performed an environmental UV test with samples being simultaneously at 100 degree, 230 degree and 350 degree C. After the test we noted that the K-film shows for all three temperatures a higher mass loss than the U-film. We also found a non-linear correlation of the activation energies for the mass loss of the K-film as a function of temperature. Additionally we found a higher loss of transmittance (UV/VIS) for the K-film and a higher degradation of the alpha/ epsilon ratio when compared to the U-film. On the latter it seems that this degradation is temperature activated.


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    Title :

    Space environmental testing of thermal controlfoils at extreme temperatures


    Contributors:


    Publication date :

    2003


    Size :

    7 Seiten, 12 Quellen



    Type of media :

    Conference paper


    Type of material :

    Print


    Language :

    English




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