Atomic Oxygen Effects on POSS Polyimides in Low Earth Orbit

Abstract

Kapton polyimde is extensively used in solar arrays, spacecraft thermal blankets, and space inflatable structures. Upon exposure to atomic oxygen in low Earth orbit (LEO), Kapton is severely eroded. An effective approach to prevent this erosion is to incorporate polyhedral oligomeric silsesquioxane (POSS) into the polyimide matrix by copolymerizing POSS monomers with the polyimide precursor. The copolymerization of POSS provides Si and O in the polymer matrix on the nano level. During exposure of POSS polyimide to atomic oxygen, organic material is degraded, and a silica passivation layer is formed. This silica layer protects the underlying polymer from further degradation. Laboratory and space-flight experiments have shown that POSS polyimides are highly resistant to atomic-oxygen attack, with erosion yields that may be as little as 1% those of Kapton. The results of all the studies indicate that POSS polyimide would be a space-survivable replacement for Kapton on spacecraft that operate in the LEO environment.

Characterization and analysis on atomic oxygen resistance of POSS/PVDF composites

“…Thus explained why the erosion profile exhibit "beaker shaped" as discussed in the aspect of first impact possibility. The phenomenon coincides with both LEO flight and ground laboratory testing [21,23].…”

“…It is proved that POSS reinforced composites exhibit good atomic oxygen resistance both in long term ground exposure and in-spaceflight test [12,21]. The atomic oxygen resistance of POSS is due to the Si O cage.…”

“…The following amendment for the simulation of atomic oxygen erosion was employed based on the empirical equation and the reported experimental results [21,[25][26][27]: (1) No interaction occurs between POSS and atomic oxygen under high atomic oxygen fluence since the impact energy is not able to break the bond of POSS. (2) Heat reaction will not occur between atomic oxygen and composite as POSS absorbs the impact energy produced by atomic oxygen (3) according to relevant references [16,26,28], the erosion yields for 3% and 10% POSS/PVDF are = 1.24 × 10 −25 cm 3 /atom and = 0.8 × 10 −25 cm 3 /atom, respectively.…”

Measurement of the Mie-Grüneisen equation of state for polyimide

“…Additionally, there are many kinds of aerospace rays. Polyimides used in the spacecraft surface layer would be in high-pressure state when the spacecraft collides with a meteoroid or orbital debris with hypervelocity, or is radiated by the aerospace rays [6][7][8][9][10][11]. Polyimides used in the IFE shells are also in the high-pressure state when radiated by powerful laser.…”

Synthesis of a Nanostructured Composite: Octakis(1-propyl-1H-1,2,3-triazole-4-yl(methyl 2-chlorobenzoate))octasilsesquioxane via Click Reaction

“…1,2 In the past years, polyhedral oligomeric silsesquioxanes (POSS) continue to be of interest for further functionalization with reactive groups to develop nano-hybrid materials. [3][4][5][6][7] They have been widely utilized to produce hybrid materials with improved properties such as enhanced thermomechanical properties, 8,9 good thermal stability, 10 atom oxygen resistance, 11 abrasion resistance, 12 and low water uptake. 13 POSS with rigid cage-like structures are a class of important nano-sized molecules consisting of an inorganic Si-O-Si core.…”