STP215: Evaluation of Rubber Deterioration by Means of Phosphorus-32

    Young, J. F.
    Research Engineer and Process Engineer respectively, Materials and Process Engineering, Douglas Aircraft Co., Santa Monica, Calif.

    Richards, C. W.
    Research Engineer and Process Engineer respectively, Materials and Process Engineering, Douglas Aircraft Co., Santa Monica, Calif.

    Pages: 6    Published: Jan 1958


    Abstract

    When an aircraft has fuel storage tanks as an integral part of the wing, joints of the wing which may come in contact with the fuel are coated with Thiokol rubber to make a positive seal. Several methods of measuring the attack of fuel on the rubber are now used. These are (1) weight of residue, (2) pull strength of dumbbell specimens, (3) elongation, and (4) swelling. Evaluating the attack by these methods is difficult because of the wide variations in the results obtained; therefore the uptake of radioactive tracer as a measure of the rubber deterioration was investigated.

    The deterioration of EC-801 rubber soaked in fuels and organic liquids as measured by phosphorus-32 was in agreement with the attack measured as per cent swell and weight of residue. The correlation is not as striking for other types of rubbers. It appears that the activity of a rubber sample is a measure of the porosity of the rubber after leaching by the fuel.


    Paper ID: STP45015S

    Committee/Subcommittee: E10.02

    DOI: 10.1520/STP45015S


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