Investigation into the Fatigue Resistance of Natural Rubber Vulcanisates

  • V. Kajornchaiyakul

    Student thesis: Master's ThesisMaster of Philosophy

    Abstract

    The fatigue resistance of dicumyl peroxide (DCP) and conventional
    sulphur cured Natural Rubber (NR) vulcanisates have been investigated.
    The rubbers were examined both with and without hot acetone extraction under nitrogen, before and after vulcanisation. Extraction reduced the fatigue life of vulcanisates made by both procedures i.e., before and after vulcanisation. The non-rubber constituents of NR were shown to exhibit anti-fatigue activity in both vulcanisates, but the effect was more pronounced in DCP vulcanisates. Extra-network
    compounds produced by both vulcanising systems did not show any adverse effect on fatigue life.

    The fatigue life of DCP vulcanisates was found to be very dependent
    on DCP loading. Below 2 parts per hundred of rubber, the fatigue
    life was found to be higher than a conventional sulphur vulcanisate
    cured to the same rheometer torque.

    The structures resulting from DCP vulcanisation of NR have been
    studied by infra-red and it is shown that aromatic compounds, almost
    certainly derived from the cumyloxy radical, are attached to the
    crosslinked polymer.

    In the presence of IPPD, the DCP cured rubbers have a lower modulus
    than the control, and attempts have been made to find coagents to
    compensate for this. Trimethylol propane trimethacrylate was shown
    to satisfy this requirement; however, it showed an adverse effect on
    fatigue life.
    Date of AwardMar 1986
    Original languageEnglish
    Awarding Institution
    • Aston University

    Keywords

    • fatigue resistance
    • natural rubber vulcanisates
    • rubber

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