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Atomic Oxygen Durability Evaluation of a UV Curable Ceramer Protective CoatingThe exposure of most silicones to atomic oxygen in low Earth orbit (LEO) results in the oxidative loss of methyl groups with a gradual conversion to oxides of silicon. Typically there is surface shrinkage of oxidized silicone protective coatings which leads to cracking of the partially oxidized brittle surface. Such cracks widen and branch crack with continued atomic oxygen exposure ultimately allowing atomic oxygen to reach any hydrocarbon polymers under the silicone coating. A need exists for a paintable silicone coating that is free from such surface cracking and can be effectively used for protection of polymers and composites in LEO. A new type of silicone based protective coating holding such potential was evaluated for atomic oxygen durability in an RF atomic oxygen plasma exposure facility. The coating consisted of a UV curable inorganic/organic hybrid coating, known as a ceramer, which was fabricated using a methyl substituted polysiloxane binder and nanophase silicon-oxo-clusters derived from sol-gel precursors. The polysiloxane was functionalized with a cycloaliphatic epoxide in order to be cured at ambient temperature via a cationic UV induced curing mechanism. Alkoxy silane groups were also grafted onto the polysiloxane chain, through hydrosilation, in order to form a network with the incorporated silicon-oxo-clusters. The prepared polymer was characterized by H-1 and Si-29 NMR, FT-IR, and electrospray ionization mass spectroscopy. The paper will present the results of atomic oxygen protection ability of thin ceramer coatings on Kapton H as evaluated over a range of atomic oxygen fluence levels.
Document ID
Document Type
Technical Memorandum (TM)
Banks, Bruce A.
(NASA Glenn Research Center Cleveland, OH, United States)
Karniotis, Christina A.
(QSS Group, Inc. Cleveland, OH, United States)
Dworak, David
(Akron Univ. Akron, OH, United States)
Soucek, Mark
(Akron Univ. Akron, OH, United States)
Date Acquired
September 7, 2013
Publication Date
April 1, 2004
Subject Category
Nonmetallic Materials
Report/Patent Number
Meeting Information
Seventh International Conference Protection of Materials and Structures from Space Environment(Toronto)
Funding Number(s)
WBS: WBS 22-319-20-E1
Distribution Limits
Work of the US Gov. Public Use Permitted.

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NameType 20040070787.pdf STI