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Effects of orbital exposure on halar during the ldef mission
| Content Provider | NASA Technical Reports Server (NTRS) |
|---|---|
| Author | Brower Jr., William E. Holla, Harish Bauer, Robert A. |
| Copyright Year | 1992 |
| Description | Thermomechanical Analysis (TMA), Differential Scanning Calorimetry (DSC), and Thermogravimetric Analysis (TGA) were performed on samples of Halar exposed on the LDEF Mission for 6 years in orbit and unexposed Halar control samples. Sections 10-100 microns thick were removed from the exposed surface down to a depth of 1,000 microns through the 3 mm thick samples. The TMA and DSC results, which arise from the entire slice and not just its surface, showed no differences between the LDEF and the control samples. TMA scans were run from ambient to 300 C; results were compared by a tabulation of the glass transition temperatures. DSC scans were run from ambient to 700 C; the enthalpy of melting was compared for the samples as a function of section depth with the sample. The TGA results, which arise from the surface of the sample initially, showed a sharp increase in the topmost 50 micron section (the exposed, discolored side) in the weight loss of 170 C in oxygen. This weight loss dropped to bulk values in the range of depth of 50-200 microns. The control sample showed only a slight increase in weight loss as the top surface was approached. The LDEF Halar sample appears to be mechanically undamaged, with a surface layer which oxidizes faster as a result of orbital exposure. |
| File Size | 509410 |
| Page Count | 26 |
| File Format | |
| Alternate Webpage(s) | http://archive.org/details/NASA_NTRS_Archive_19930003600 |
| Archival Resource Key | ark:/13960/t3wt3kv9p |
| Language | English |
| Publisher Date | 1992-09-01 |
| Access Restriction | Open |
| Subject Keyword | Nonmetallic Materials Earth Orbital Environments Chlorofluorocarbons Melting Postflight Analysis Enthalpy Thermogravimetry Spaceborne Experiments Environmental Tests Heat Measurement Ethylene Compounds Glass Transition Temperature Thermodynamic Properties Long Duration Exposure Facility Surface Layers Ntrs Nasa Technical Reports Server (ntrs) Nasa Technical Reports Server Aerodynamics Aircraft Aerospace Engineering Aerospace Aeronautic Space Science |
| Content Type | Text |
| Resource Type | Article |
