Volcanic meter

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Vulkameter in use: The chamber is open, the test specimen lies on the lower half of the chamber , the measurement is completed.

A vulcanometer is a measuring device with which the behavior of a crosslinkable mixture of polymers , mostly rubber , and aggregates during vulcanization can be examined. As a response of the material to a forced oscillating deformation in a heated and divided chamber, characteristic measured values ​​such as elastic and viscous torque are obtained as a function of time. It therefore resembles a rheometer in its functionality .

Measuring principle

A defined amount of an unvulcanized mixture is exposed to pressure and temperature in a metal chamber and deformed in an oscillating manner. It will be between

  • Linear thrust vulcanoes
  • Torsional thrust vulcanized meters with rotor
  • Torsional thrust vulcanized meters without a rotor with an open or closed chamber

distinguished.

The vulcanization is now using it form molecular bridges and the mixture crosslinks rapidly. In the case of torsional thrust vulcanoes, a chamber part or the rotor moves back and forth a few degrees (0.1 - 2 °) at a frequency of 0.05 to 2  Hz . The torque required to maintain the movement is recorded and transmitted to a recorder or PC together with the deflection angle, temperature and pressure. The functionality is thus similar to that of a rheometer.

When the process is finished, an envelope curve of the time-torque curve is obtained. In the case of rubber mixtures, the envelope curve initially drops to a minimum value, then increases as the crosslinking reaction begins and approaches a final value. The torque required for deformation is therefore a measure of the progress of the reaction.

For example, both the degree of crosslinking after a certain time can be determined as well as the time required to crosslink the material to a desired proportion.

Monitoring and targeted development of rubber compounds would not be possible without Vulkameter.

literature

  • Fritz Röthemeyer, Franz Sommer: Rubber technology: materials, processing, products . 2nd Edition. Hanser, Munich / Vienna 2006, ISBN 978-3-446-40480-9 , Chapter 6.4.3.1 Vulkametrie, p. 465–467 ( limited preview in Google Book search).

Norms

  • DIN 53529-1: 1983-03: Testing of rubber and elastomers; Volcanometry; General working principles
  • DIN 53529-2: 1983-03: Testing of rubber and elastomers; Volcanometry; Determination of the vulcanization process and reaction kinetic evaluation of crosslinking isotherms
  • DIN 53529-3: 1983-06: Testing of rubber and elastomers; Volcanometry; Determination of the cross-linking behavior with rotorless vulcanized meters
  • DIN 53529-4: 1991-04: Testing of rubber and elastomers; Volcanometry; Determination of the crosslinking behavior with a Vulkameter with rotor
  • ISO 3417: 2008-12: Rubber and elastomers - Determination of the crosslinking behavior using a vulcanizer with rotor
  • ISO 6502: 1999-12: Rubber - Guide to the use of volcanoes