Accession Number : ADA310201

Title :   Effects of Heat Sterilization and Vacuum Exposure on Some Low-Density Heat-Shield Materials.

Descriptive Note : Technical note,

Corporate Author : NATIONAL AERONAUTICS AND SPACE ADMINISTRATION HAMPTON VA LANGLEY RESEARCH CEN TER

Personal Author(s) : Sykes, George F., Jr

PDF Url : ADA310201

Report Date : MAR 1970

Pagination or Media Count : 35

Abstract : The effects of dry heat sterilization for 92 hours at 135 deg C in flowing nitrogen and 200 hours of exposure at 66 deg C to pressures in the 10(-5)-N/m(2) range upon the thermochemical properties of five blown-foamed and five molded composite heat-shield materials have been determined. Differential thermal analysis (DTA) was employed to follow the changes which occurred in each material as a result of sterilization and vacuum exposure. The results show that, on the whole, the composite materials have greater sterilization mass losses than the foamed materials and that the high-vacuum losses of both types of material are approximately equal. During high-vacuum exposure, the mass loss was approximately 1 percent after 200 hours of exposure, and at 200 hours the rate of mass loss ranged between 2.5 x 10 (-4) and 11.1 x 10(-4) percent per hour for most of the materials.

Descriptors :   *COMPOSITE MATERIALS, *HEAT SHIELDS, EXPOSURE(GENERAL), MASS, VACUUM, RATES, NITROGEN, THERMOCHEMISTRY, LOSSES, LOW DENSITY, GAS FLOW, FOAM, STERILIZATION, DIFFERENTIAL THERMAL ANALYSIS, HIGH VACUUM, MOLDING MATERIALS, LOW HUMIDITY.

Subject Categories : Laminates and Composite Materials
      Protective Equipment

Distribution Statement : APPROVED FOR PUBLIC RELEASE