| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 1689052 | Vacuum | 2011 | 8 Pages |
Performance deterioration with time is one of the most important issues in a vacuum insulation panel (VIP), which is mostly due to the inner gas pressure rise. Outgassing from the interior of core materials is the major gas source when the core material is a polymer. Outgassing characteristics of a polycarbonate as the VIP’s core material are examined theoretically and experimentally. To measure the outgassing rate, specific outgassing tests are carried out using a pressure rise method. Diffusive outgassing mechanism is discussed based on the Fick’s law. As the result, the total amount of dissolved gas and the diffusion coefficients of various gases in the polycarbonate are obtained by using the measured outgassing rate. Temperature dependence of the diffusion coefficient of nitrogen is also examined. It is shown that the outgassing rate of polymer core materials can be significantly reduced to a negligible level by a baking pre-treatment in vacuum and/or by a metal coating on the polymer surface.
Research highlights► Diffusive outgassing is the major residual gas source in the VIP having a polymer core. ► Diffusion coefficients are measured by using a short-term outgassing behavior. ► The measured diffusion coefficients of N2 and O2 are in accordance with the references. ► Surface desorption effect of H2O and CO2 is greater than that of N2 and O2. ► Outgassing rate can be lowered by a baking pre-treatment or metal coating on the surface.
