NASA 1999 SBIR Phase I


PROPOSAL NUMBER: 99-1 25.01-1685 (Chron: 990373)

PROJECT TITLE: Electrically Conductive Thermal Control Coatings

TECHNICAL ABSTRACT (LIMIT 200 WORDS)

A new, photoconductive polymer system based on silylene-silicone copolymers is proposed for evaluation as a base resin for spacecraft coating materials. These coatings can be tailored to provide low solar absorbance, high emissivity at ambient spacecraft surface temperature, atomic oxygen resistance, and resistance to surface charging by ion and electron impact. The coatings are tough, abrasion resistant, 100% solids formulations; no solvents are required. Cure of the coating is initiated by irradiation with ultraviolet (UV) light, which allows cure control that is independent of temperature and provides long shelf life. Our approach to the formulation of spacecraft coatings will involve the synthesis of a curable resin containing polysilylene chains. We believe that polysilylene chains terminated with epoxy substituted polysiloxanes (silicones) afford the most viable route to a curable system. We will use the established photoconductivity of the polysilylene fragments to achieve an illuminated (light or ionizing radiation) conductivity for neutralizing deposited charge and their reactivity toward atomic oxygen to provide erosion protection. Polysilylenes form monolayers of silica during attack, which can effectively block further reaction. We propose to fill these systems, at or below the percolation limit with glass particles that are coated with a conductive indium/tin oxide layer to tailor their absorbtivity and emissivity and to provide the surfaces for generation of free-charge carriers. Previous work at Adherent Technologies has resulted in polysilylenes that have reactive ends capable of copolymerization with epoxy-terminated siloxane oligomers to form crosslinkable resin systems. Suitable tailoring of these copolymers should give liquid, ultraviolet light curable resins that can be the basis of solvent-free coating systems.


POTENTIAL COMMERCIAL APPLICATIONS

Initial applications will be in government-sponsored space and communications programs. However, the materials should find niche markets in areas where high temperature stability, corrosion resistance, and shielding or static discharge mitigation are required. The properties expected for these resins are unique. We anticipate that new and unpredictable applications will evolve as the resins are characterized. This is a new system, with an unusual combination of co-fragment characteristics that may well become of general interest. They will provide an example of molecular engineering to achieve a specific goal.



NAME AND ADDRESS OF PRINCIPAL INVESTIGATOR

 
Dr. Andrea E. Hoyt 
Adherent Technologies, Inc.
9621 Camino del Sol NE
Albuquerque , NM 87111 - 1522

NAME AND ADDRESS OF OFFEROR


Adherent Technologies, Inc. 
9621 Camino del Sol NE
Albuquerque , NM 87111 - 1522