Low-density polyethylene (LDPE) films were exposed at an altitude of 40 km over a 3 day NASA stratospheric balloon mission from Alice Springs, Australia. The radiation damage, oxidation and nitration in the LDPE films exposed in stratosphere were measured using ESR, FTIR and XPS spectroscopy. The results were compared with those from samples stored on the ground and exposed in a laboratory plasma. The types of free radicals, unsaturated hydrocarbon groups, oxygen-containing and nitrogen-containing groups in LDPE film exposed in the stratosphere and at the Earth's surface are different. The radiation damage in films exposed in the stratosphere are observed in the entire film due to the penetration of high energy cosmic rays through their thickness, while the radiation damage in films exposed on the ground is caused by sunlight penetrating into only a thin surface layer. A similarly thin layer of the film is damaged by exposure to plasma due to the low energy of the plasma particles. The intensity of oxidation and nitration of LDPE films reflects the difference of atmospheric pressure on the ground and in the stratosphere. The high-density radiation damage of the LDPE films above the ozone layer in the stratosphere is caused by primary cosmic rays as well as collision induced cosmic ray air showers, and is consistent with the measured flux of cosmic radiation. The results show, that stratospheric flights can be used to simulate the effects of space environments during interplanet space flights for the purposes of investigating the degradation of polymer materials.
Radiation damage of polyethylene exposed in the stratosphere at an altitude of 40 km
Polymer Degradation and Stability ; 98 , 8 ; 1526-1536
2013
11 Seiten, 55 Quellen
Aufsatz (Zeitschrift)
Englisch
Polyethylen , Strahlungsschädigung , Stratosphäre , kosmische Strahlung , dünne Schicht , Australien , Oxidation , ungesättigter Kohlenwasserstoff , Sauerstoff , Stickstoff , Hochenergie , Niederenergie , Oxidationsgrad , atmosphärischer Druck , hohe Dichte , Ozonschicht , Universum , Luft (gasförmiger Stoff) , Raumfahrt , Polymerwerkstoffe
High altitude or stratosphere flying
Engineering Index Backfile | 1936
|High altitude or stratosphere flying
Engineering Index Backfile | 1937
|Stratosphere balloon altitude, barometric and photogrammetric
Engineering Index Backfile | 1938
|High-Altitude Aircraft and the Stratosphere
NTIS | 1975
|