Atomic oxygen effects on POSS polyimides in low earth orbit.

Area of Science:

• Materials Science
• Aerospace Engineering
• Polymer Chemistry

Background:

• Kapton polyimide is a critical material for spacecraft components like solar arrays and thermal blankets.
• Exposure to atomic oxygen in low Earth orbit (LEO) causes severe degradation of Kapton.
• Existing materials face significant challenges due to the harsh LEO environment.

Purpose of the Study:

• To develop a more durable alternative to Kapton for LEO applications.
• To investigate the protective mechanisms of polyhedral oligomeric silsesquioxane (POSS) in polyimide matrices.
• To assess the atomic oxygen resistance of POSS-enhanced polyimides.

Main Methods:

• Copolymerization of POSS monomers with polyimide precursors.
• Incorporation of silicon and oxygen at the nanoscale within the polymer matrix.
• Laboratory and space-flight experiments to evaluate material degradation under atomic oxygen exposure.

Main Results:

• POSS polyimide forms a protective silica passivation layer upon exposure to atomic oxygen.
• This silica layer effectively shields the underlying polymer from degradation.
• POSS polyimides exhibit significantly reduced erosion yields, up to 99% less than Kapton.

Conclusions:

• POSS polyimide demonstrates exceptional resistance to atomic oxygen attack in LEO.
• The formation of a silica passivation layer is key to its enhanced durability.
• POSS polyimide is a promising, space-survivable replacement for Kapton in LEO spacecraft applications.