An oven design for torsional rheometers

Abstract

A newly designed oven for rheological characterisation of polymer melts is presented which relies upon conduction and radiation rather than convection to heat the polymer. The design involves three concentric heating elements, all controlled independently to ensure a stable thermal atmosphere. The overshoot on heating is minimal (10 K, and this was due to opening the oven for sample trimming; the overshoot is 3 K if the oven is not opened) and the results of a typical dynamic shear test show that rheological properties attain their equilibrium values very rapidly (25 min after start-up of the oven fro room temperature, and 15 min after the sample was placed in the rheometer). The temperature of the sample was maintained at ±0.5 K, thus, a stable thermal environment was successfully attained.