Recent developments in shear rheometry of uncured rubber compounds I. Design, construction and validation of a sliding cylinder rheometer

A sliding cylinder rheometer (SCR) was built in order to investigate the sp ecific rheological properties of rubber compounds at very low shear rate. T he concept of the SCR is actually derived from the plate rheometer, whose g eometry has been rolled to improve control of the shearing conditions, An a nnular gap between two cylinders is obtained and the material is sheared in the axial direction owing to the linear motion of the inner cylinder. This moving (or 'sliding') cylinder can be displaced either by hanging a weight (crcep- or constant stress-mode) or by pulling it by means of the crosshea d of a tensile machine (constant speed mode). Reliability and reproducibili ty of the measurements are shown to be good. Results of the rheological tes ts with a carbon black-polybutadiene compound are given together with data from capillary and Mooney viscometers. Alignment of all experimental data i s excellent, thus demonstrating the validity of SCR measurements, The flexi bility and capabilities of the SCR make it a cheap, accurate and sensitive rheological device, and most likely a valuable tool in the viscoelastic ana lysis of complex polymer systems, (C) 1999 Elsevier Science Ltd. All rights reserved.