Screening of liquid photopolymer resins exposed to high-vacuum

Abstract Photopolymers are promising materials for in-space manufacturing, whether for continuous extrusion or structural bonding. However, they must be processed as a liquid under high vacuum, which can alter viscosity, curing behavior, or mechanical properties. Furthermore, high outgassing can contaminate spacecraft surfaces. To study the influence of high vacuum on the resins in their liquid phase, Delo Katiobond GE680, Delo Katiobond OB678, Polymer-G EPV9511, and Loctite AA3301 LC were exposed to high vacuum. Outgassing was quantified for both liquid and cured samples. Viscosity increased in all resins, and UV-curing efficiency generally decreased. EPV9511 maintained stable mechanical properties, whereas the Delo and Loctite resins exhibited reduced stiffness at 45 °C. All resins exceeded 1% total mass loss in their liquid state, but cured GE680 and OB678 met low-outgassing criteria. GE680 and EPV9511 showed the highest vacuum stability and appear suitable for in-space processing when volatile components are minimized through pre-degassing.