The Rheometrics RDA-III high-torque controlled-strain rheometer uses either serrated or smooth parallel plates of 25 mm in diameter. For a usual test, disks of approximately 1 mm thickness are analysed. The compression force can be varied during the test to allow measuring the expansion and contraction of the sample. On the contrary, the plate gap can be kept constant to record the force. The furnace surrounding the sample can be purged with a constant flow of N2 for pyrolysis tests or air for combustion tests. Standard tests such as dynamic temperature ramp tests, strain sweep tests and frequency sweep tests can be carried out in the samples. The maximum operating temperature is 600°C. The storage modulus (G'), the loss modulus (G), the complex viscosity (η*), the phase angle (δ) and the change in plate gap (ΔL) can be recorded. The rheometer can analyse viscoelastic materials, with predominantly solid-like behaviour such as coal, biomass and polymers. It cannot analyse liquids as the viscosity in these materials is too low for the detection limits of the rheometer.
Model: RDA III
Manufacturer: Rheometric Scientific