Overview

General Description

The TA Instruments DHR-3 Discovery Hybrid Rheometer is a highly versatile instrument that characterizes mechanical behavior of liquids, viscoelastic materials, and solids as a function of shear rate, oscillation frequency, time, and/or temperature.  There are several test modes and geometries available.  Flow mode allows a user to measure viscosity as a function of shear rate, stress, time, and/or temperature.  Oscillation mode allows a user to measure viscoelastic properties, such as G', G'', and tan(δ) as a function of frequency, stress/strain, time, and/or temperature.  Step Transient mode allows a user to set up creep and stress relaxation tests to measure compliance, relaxation modulus, and other parameters associated with time-dependent material behavior.  Finally, Dynamic Mechanical Analysis (DMA) mode allows measurement of viscoelastic properties of solids via tensile, bending, or torsional tests.  The various geometries allow certain tests, material states, or quantities of material to be used successfully.  Geometries available are upper cone (25 or 40 mm), upper plate (8 or 25 mm), lower Peltier plate with precise temperature control, 25 mm lower plate for use with environmental test chamber, concentric cylinders, three-point bending (solid materials), linear tension (solid materials), and the UV curing accessory.  A summary of the various test modes and geometries is given in the graphic below (click to download and enlarge).

Environmental Control

Precise temperature control is critical to many rheological measurements, as the mechanical behavior under study is often sensitive to temperature.  Various strategies are available for environmental control, but not all geometries allow the same temperature range and heating rate.  Please see the Specifications section below for more details.  In addition to temperature control, humidity control accessories are available.  (In most cases, samples are adequately contained so that the exposure to ambient relative humidity at the edge is not significant.  However, for moisture sensitive samples, this can be an important option.)  Some geometries also have partial or complete traps to reduce or eliminate evaporation of volatile solvents from samples during testing.

Dielectric Test Mode

In addition to the mechanical tests already described, the appropriate geometry accessories and an LCR meter are available for testing dielectric properties.

Specifications

The Peltier plate allows temperature control (from below only) from 0 to 200°C and heating rate up to 20°C/min. 

The Peltier concentric cylinders allows temperature control (from outside only) from 0 to 150°C and heating rate up to 13°C/min. 

The environmental test chamber (ETC) allows temperature control from -160 to 600°C and heating rate up to 60°C/min

Technology Overview

Sample Requirements and Preparation

Standard Operating Procedure

Questions & Troubleshooting

Process Library

References