Continuous Measurement of Rubber Vulcanization with the Agfa Vulcameter

    Published: Jan 1965

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    The Agfa Vulcameter was the forerunner and inspiration for more elaborate types of instrumentation now used to follow the course of vulcanization of laboratory test specimens. Procedures are described which enable the Vulcameter to fulfill most of the purposes of such instruments. The temperature control system has been modified so that the temperature rise in the specimen corresponds rather closely to that of a standard test sheet in a mold. The most serious objection to the Vulcameter has been the absence of pressure on the specimens allowing porosity to develop. This difficulty has been mitigated by using thinner specimens, about 0.04-in. thick, and practically eliminated by containing the specimen in a specially designed, low-pressure cell. Suitable calibration curves permit the conversion of the recorded traces to plots of shear modulus. The capabilities of the instrument for determining pertinent vulcanization and processing parameters are illustrated. Activation energies were determined for the vulcanization of a variety of rubber compounds. Vulcameter measurements of the shear modulus of uncured compounds and of scorch times correlated rather well with values from the Mooney viscometer.

    Author Information:

    Gehman, S. D.
    Manager and physicist, The Goodyear Tire & Rubber Co., Akron, Ohio

    Ogilby, S. R.
    Manager and physicist, The Goodyear Tire & Rubber Co., Akron, Ohio

    Committee/Subcommittee: D11.10

    DOI: 10.1520/STP47207S

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