STP1326

    The use of Thermal Analysis to Assess Oxidative Damage in Polyolefins

    Published: Jan 1997


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    Abstract

    During the thermal oxidation of polyolefins, exemplified by isotactic polypropylene, few observable physical and chemical changes occur until embrittlement or similar failure. The increasing oxidative and auto-oxidative behavior that accompanies oxidation can be measured as a reducing oxidation induction time using isothermal thermal analysis. Alternatively, dynamic thermal analysis (DSC or TGA) may be used more conveniently to record the shift to lower temperatures of the post-fusion, oxidative exotherm quantified as an onset (Ton) temperature. This paper collates data from a number of previous and current studies on the oxidative behavior of oriented polypropylene tapes and filaments exposed at elevated (130°C) temperature in air. During exposure, Ton values decrease according to a power law dependence with time and these shifts may be used to assess degrees of oxidation present in aged specimens. The implications of these shifts are discussed in tenns of monitoring in-service behavior of exposed polyolefins and their relationship to oxidative and auto-oxidative mechanisms are discussed.

    Keywords:

    thermal analysis, DSC, TGA, polypropylene, oxidation, auto-oxidation, oxidative degradation


    Author Information:

    Horrocks, AR
    Professor and research student, Bolton Institute, Bolton,

    Mwila, J
    Manager, Dunlop (Z) Limited, Ndola,

    Liu, M
    Professor and research student, Bolton Institute, Bolton,


    Paper ID: STP13812S

    Committee/Subcommittee: E37.01

    DOI: 10.1520/STP13812S


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