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  • Water vapor absorption in Viton - gravimetric and vacuum measurement
    Sefa, Makfir ; Šetina, Janez ; Erjavec, Bojan, 1950-2023
    A cost effective solution for joining different vacuum parts is by using elastomeric gaskets, but there is a disadvantage of absorption and permeation of atmospheric gases in elastomeric materials. ... It is well known that particularly water vapor from humid air permeates through elastomer gaskets and limits the lowest attainable pressure level in such vacuum systems to high vacuum range. Most common gasket material is fluoroelastomer known under trade name Viton. A limited data on atmospheric water vapor permeability of Viton can be found in vacuum literature. The results are also not consistent and important parameters such as relative humidity and temperature are often missing. In the first part of experiment a sample gasket has been degassed in high vacuum for several weeks to remove practically all dissolved water vapor. After that it was exposed to the ambient atmosphere with controlled temperature and relative humidity. The water vapor uptake versus time of exposure was measured gravimetrically with a precise balance. In the second part of experiment a gasket was kept for several weeks under well controlled ambient conditions and after that placed in a vacuum system for outgassing measurements. The outgassed amount of water vapor was compared with gravimetric measurements of absorbed water vapor. Results show comparable amount of absorbed water vapor for both completely different measurement amethods. Water absorption is a very slow process and it takes more than a week to reach equilibrium after a change of partial pressure of water vapor. Viton can absorb considerable amount of water vapor, of the order of 0.1% of its mass at room temperature and at 50% relative humidity.
    Vir: Programme and book of abstracts (Str. 133)
    Vrsta gradiva - prispevek na konferenci
    Leto - 2010
    Jezik - angleški
    COBISS.SI-ID - 814250

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