ISO 458-1:1985

Plastics — Determination of stiffness in torsion of flexible materials — Part 1: General method

Specification of a general method for the determination of the stiffness in torsion at various temperatures, particularly below 0 °C. An observation of torque and angle of deflection is made after an arbitrarily fixed time of load application, using the specified testing apparatus. This procedure is employed at a single temperature or at selected temperature intervals over a range specified for the material to be tested. The stiffness in torsion is expressed as the apparent torsional modulus of elasticity for each temperatur.