| Abstract: | A torsional creep and recovery apparatus has been designed and constructed to measure extremely wide ranges of recoverable creep compliance (10?10 to 10?2 cm.2/dyne) and viscosity (10?1 to 1016 poises) within the temperature range ?60 to 220°C. Friction is avoided by supporting the moving element, the rotor, in a magnetic field, inducing the required torque with a drag cup motor, and monitoring the angular displacement with a light lever and a light following recorder. Measurements of recoverable compliance can be made further into the region of time scale which is dominated by viscous deformation than has been heretofore possible. In situ sample manipulation of viscoelastic liquids is utilized. Measurement is made on liquid cylinders between circular stainless steel platens. Results which have been obtained on a 1.22 × 105 molecular weight polystyrene are presented to illustrate the range of possible measurements and to indicate the value of such results covering up to six logarithmic decades of time scale. |
