Project Title:

Synthesis and Characterization of Protective Coatings for Aerospace Materials

04.06-0452
Synthesis and Characterization of Protective Coatings for Aerospace Materials
Mercor, Incorporated
2448 Sixth Street
Berkeley
CA
94710
Riffle
Judy S.
957
49,684
JPL

Abstract:

Linear, polydimethlsiloxane-polyimide block copolymers may prove to be useful as
high performance coatings in applications where extreme environmental conditions
will be encountered.  The objective of this project is to develop a coating material
which would protect the underlying substrate against degradation due to atomic oxygen
bombardment.  In addition, this coating material should also be hydrolytically, oxidatively,
and thermally stable over a wide temperature range.  There is evidence that polysiloxane
surfaces react with atomic oxygen to form protective silicon dioxide coatings.  Polyimide
homopolymers are known to be thermally and hydrolytically stable and to possess excellent
mechanical properties.  Therefore, chemically, it is believed that a polysiloxane-polyimide
copolymer would make an excellent coating.  Unfortunately, polyimides are normally
intractible, infusible polymers.  Polysiloxane-polyimides made to date are either
insoluble materials or have very low upper use temperatures due to extremely short
block lengths of the rigid component.  The feasibility of development of a soluble
coating material having the polysiloxane-polyimide block copolymer structure will
be evaluated using three basic schemes:
		1.  Copolymer synthesis via the reaction of diisocyanates,
		2.  Polyamide-imide-siloxane copolymer synthesis, and finally,
		3.  Copolymer synthesis employing a Michael reaction for chain
                extension.