STP997: Thermogravimetric Characterization of Elastomers and Carbon-Filled Rubber Composites for Military Applications

    Macaione, DP
    Research chemist and researchers, Polymer Research Division, U.S. Army Materials Technology Laboratory, Watertown, MA

    Sacher, RE
    Research chemist and researchers, Polymer Research Division, U.S. Army Materials Technology Laboratory, Watertown, MA

    Singler, RE
    Research chemist and researchers, Polymer Research Division, U.S. Army Materials Technology Laboratory, Watertown, MA

    Pages: 11    Published: Jan 1988


    Abstract

    A number of elastomeric materials used in Army tank track pads have been analyzed by several thermal analysis techniques including thermogravimetric analysis. More than 50 different materials have been evaluated. In general, the test specimens contained styrene-butadiene (SBR), butadiene (BR), and natural (NR) rubber in mono-, di-, or triblend systems.

    Thermogravimetric analysis (TGA) was used to determine the percentage of highly volatile organics, elastomer(s), carbon black, and inorganic residue for each sample. An acetone extracted sample was compared to a nonextracted sample to validate the measurement of highly volatile material. The TGA data illustrated that the percent organic and percent carbon black determinations were quite consistent with the known formulations, but the percentage of inorganics was variable in a number of samples. Ash determinations obtained using larger specimens in a muffle furnace more closely approximated the known values. The DTG curve was used to determine the type of elastomer contained in each track pad. NR exhibited a peak at approximately 365°C (689°F) while SBR, BR, and SBR-BR exhibited a peak at approximately 450°C (842°F). TGA can quantify SBR and/or BR versus NR, but cannot differentiate between SBR and BR, nor can TGA differentiate between cured versus uncured systems. It is necessary to employ differential scanning calorimetry (DSC) to detect uncured systems using the cure exotherm that occurs between 150 to 200°C (302 to 392°F). Finally, the application of thermogravimetric analysis to the tentative identification of foreign track rubber samples is considered.

    Keywords:

    thermal analysis, elastomers, track pads, rubber, carbon black


    Paper ID: STP26398S

    Committee/Subcommittee: E37.04

    DOI: 10.1520/STP26398S


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