Accession Number : AD0628537

Title :   LOW-LOSS STYRENE-TYPE FOAM-IN-PLACE ENCAPSULATING RESINS,

Corporate Author : HARRY DIAMOND LABS WASHINGTON D C

Personal Author(s) : ENGELHARDT,F. J. O.

Report Date : 15 OCT 1965

Pagination or Media Count : 24

Abstract : Low-dielectric-loss styrene-type foam-in-place encapsulating resins are not available commercially. Such a resin has now been developed. A propellant was added to the catalyzed styrene-polystyrene mixture; as the temperature of the polymerizing resin rose, the propellant expanded the resin into a cellular structure. Homogeneous foams were obtained in the presence of finely powdered polymers, which acted as bubble nucleators. The resultant rigid foams had dielectric constants ranging from 1.2 to 1.8, and loss tangents from 0.0002 to 0.001 over the frequency range 102 and 108 cps. Some of these materials had remarkably flat loss-frequency curves, losses ranging only between 0.0004 and 0.0005 over the same frequency range. Densities were varied between 0.194 and 0.850 g/cu cm, or between 12 and 53 lb/cu ft. These data indicate the usefulness of the new cellular materials as rf encapsulating resins. (Author)

Descriptors :   (*ENCAPSULATION, STYRENE PLASTICS), (*STYRENE PLASTICS, ENCAPSULATION), (*EXPANDED PLASTICS, ENCAPSULATION), STYRENES, PROPELLANTS, POLYMERIZATION, POWDERS, DIELECTRIC PROPERTIES, RADIOFREQUENCY, COMPRESSIVE PROPERTIES, DENSITY

Subject Categories : Electrical and Electronic Equipment
      Plastics

Distribution Statement : APPROVED FOR PUBLIC RELEASE