Outgassing properties of PI aerogel and CF/PTA composites before and after electron/ultraviolet irradiation

Abstract

In this study, different test standards were employed to investigate the vacuum outgassing behavior of Polyimide (PI) aerogels and Carbon Fiber/polytriazole resin (CF/PTA) materials both before and after exposure to electron/ultraviolet irradiation. In-situ vacuum outgassing characteristics of PI aerogel and CF/PTA composites showed a high sensitivity to temperature in terms of Collected Volatile Condensable Material (CVCM), with depositions at 298K accounting for only 0.1%–0.2% of the Total Mass Loss (TML), respectively. The relationship between the TML of PI aerogel and CF/PTA composite over time was found to conform to a quasi-first-order kinetic equation. After electron irradiation, degradation of the PI aerogel resulted in an increase in CVCM, whereas CF/PTA composites exhibited an elevated TML, especially in CVCM after 1 MeV electron irradiation. In-situ mass spectrometry results obtained under vacuum ultraviolet irradiation revealed that this form of irradiation induced surface activation of PI aerogel, leading to a significant decrease in the proportion of H₂O in the outgassing products and a notable reduction in the CVCM.