Rubber Industrial
In rubber industrial, rubber is divided into two groups’ namely natural rubber and synthetic rubber. For many years, rubber industrial have sought process to control the processability of their products. The standard Mooney measurement has been used for more than fifty years to characterise the rubber viscosity and the onset of cure process of rubber compounds.
The correct viscosity is important to ensure acceptable mixing and processing characteristics. According to standard test, the measurement Mooney viscosity of a material based on the torque value read after subjecting sample to the shearing rotor for 4 minutes, at 2 rpm, in the closed heated chamber. The Mooney viscosity is directly to the torque which is the resistance of rubber to the turning rotor. Commonly, the test procedure follows in ASTM 1646 or ISO 289. The example of the standard viscosity test conditions is showed below.
Reference: ASTM 1646 - 04
Figure 1 The details on rubbers and compounds for precision testing programs.
Reference: ASTM 1646 - 04
Figure 2 Torque curve from a Mooney viscosity test plus stress relaxation.
The information obtained from a Mooney viscometer could include:
- Mooney peak, which is the initial peak at the start test, it is a function of the green strength of rubber.
- Mooney viscosity, which depends on the molecular weight and molecular weight distribution, molecular structure and non – rubber constituents.
- Stress relaxation, which is the response to a suddenly stop deformation after the rotor of the Mooney viscometer stops.