Sealants collector application

Until very recently almost no new materials were developed for the solar collector industry, which is essentially in its infancy. This investigation was performed to help Identify deficiencies of the available sealant materials with the expectation, which we believe is beginning to be realized, that this would lead to development of superior materials for solar collector applications, ... 

Elastomeric materials are used in thermal solar collectors as gasket and caulking compounds. In addition to these sealant applications, polymeric materials are also widely employed as thermal insulation and occasionally as glazing and frame components. This paper provides a supplement and a continuation of a previously reported study( 1) of the endurances of several commercially available sealants to the harsh environment of the collector. 

The above criteria were employed to select several commercially supplied Class PS elastomers for laboratory screening by employing selected tests taken from National Bureau of Standards NBSIR 77-1437(j4) and ANSI/ASTM D-3667-78 specifications for "Rubber Seals Used in Flat-Plate Solar Collectors". Four silicone, three EPDM, two fluorocarbon, three epichlorohydrin, one ethylene-acrylic, one polyacrylic, one chlorosulfonated polyethylene, one bromobutyl and two butyl rubbers were studied in these screening tests. These materials are identified in Table I and those compositions which were revealed by their manufacturers are shown in Table II. Undoubtedly some materials which should have been included were omitted however, we hope that this sampling will provide an indication of the applicability of a wide range of materials for use as sealants in thermal solar collectors. 

Adhesives and sealants used for the aerospace structures must endure severe environments. Another family of adhesive materials has also been developed for solar collectors, presumably based on the same ability to endure severe environments. Though there are different kinds of severe environments, conventional polymers generally do not survive in the solar collector environment. We shall discuss those adhesive materials used for solar applications in the following section. 

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