IUVSTA 15th International Vacuum Congress (IVC-15), AVS 48th International Symposium (AVS-48), 11th International Conference on Solid Surfaces (ICSS-11)
    Vacuum Science & Technology Wednesday Sessions
       Session VST-WeA

Paper VST-WeA1
Kinetic Parameters of Materials Outgassing: Experimental Determination Using Thermoelectric Quartz Crystal Microbalance

Wednesday, October 31, 2001, 2:00 pm, Room 125

Session: Gas Sorption Phenomena II
Presenter: E. Grossman, Soreq NRC, Israel
Authors: I. Gouzman, Soreq NRC, Israel
M. Murat, Soreq NRC, Israel
E. Grossman, Soreq NRC, Israel
Y. Noter, Soreq NRC, Israel
Y. Lifshitz, Soreq NRC, Israel
Correspondent: Click to Email
The outgassing of polymer-based materials is a concern for all space-related applications. The knowledge of the kinetic parameters characterizing outgassing of materials is of great importance since they are used to predict the potential contamination and the associated degradation of space systems. In the present work thermoelectric quartz crystal microbalance (TQCM), incorporated in a modified ASTM E 595 standard outgassing system, was used to measure the kinetics of spacecraft materials' outgassing under high vacuum and elevated temperatures. The measurements were carried out by collecting the outgassed species on the TQCM sensor surface. The experimental procedure consisted of the following steps: (i) a stepwise increase of the sample temperature in the 25 - 125°C range, while keeping the TQCM at a constant temperature (25 or 0°C), (ii) cooling the sample and keeping it at room temperature without changing the TQCM temperature in order to isolate the contaminants re-emission process, and (iii) increasing the TQCM temperature in several steps, studying the effect of the temperature on the re-emission kinetics. An analytical model was developed to derive the outgassing and re-emission kinetic parameters from the experimental data. The system capabilities were demonstrated by studying the outgassing kinetics of several materials that included polysiloxane and polyurethane based black coatings (S2 and PU1, respectively, both manufactured by MAP, France) as well as a closed cell polymethacrylimide foam (Rohacell, manufactured by Rohm, Germany). Outgassing and residence times, activation energies, and the contamination potential of different components of the outgassed products were calculated based on the proposed model. The derived parameters can be used to predict the outgassing and contamination profiles of space systems, both on the ground (e.g. in a thermal vacuum tests) and in space.