Thesis
Characterizing the helium permeability of polymer films and cryogenic temperatures
Washington State University
Master of Science (MS), Washington State University
12/2019
DOI:
https://doi.org/10.7273/000003979
Handle:
https://hdl.handle.net/2376/124425
Abstract
Cryogenic propellant bladders could substantially improve propellant storage and slosh characteristics in microgravity conditions. However, an experimental effort in the 1970's showed an unacceptably high permeation rate of hydrogen and helium through thin polymer films (candidate materials for bladders) at cryogenic temperatures. A hypothesis for the increase is the relatively large thermal de Broglie wavelength of hydrogen and helium molecules at cryogenic temperatures, increasing the hopping rate of the molecules and resulting bulk permeation. This hypothesis was tested by measuring the leak rate of helium through thin films of polyether ether ketone (PEEK), polyetherimide (Ultem®), ethylene vinyl alcohol (EVOH), and polyethylene terephthalate (PET) from 180 - 30 K.A calibrated helium mass-spectrometer and custom sample test-cell were utilized. The measurements indicate that permeation follows an Arrhenius relation with decreasing temperature until the limit of the sensor resolution was achieved below ~ 90 K. The anomalous increase in permeability with reducing temperature observed in the historical 1970's study was only reproduced with samples known to have developed leaks in the sealing gaskets. This finding indicates that cryogenic permeability should not be a primary limitation to the use of propellant bladders.
Metrics
Details
- Title
- Characterizing the helium permeability of polymer films and cryogenic temperatures
- Creators
- Kjell G. Westra
- Contributors
- JACOB W. LEACHMAN (Advisor) - Washington State University, School of Mechanical and Materials Engineering
- Awarding Institution
- Washington State University
- Academic Unit
- School of Mechanical and Materials Engineering
- Theses and Dissertations
- Master of Science (MS), Washington State University
- Publisher
- Washington State University
- Identifiers
- 99900890802901842
- Language
- English
- Resource Type
- Thesis