Abstract
Polypropylene (PP) has been widely used in various industrial fields as substitute materials of metals. Evaluation of the creep life is one of the most important problems. However. the conventional test methods. such as tensile test are time and cost consuming. Then. indentation method is applied to evaluate the creep characteristic of PP under various conditions of temperatures and loading rates. The results confirmed that the indenting displacement depends on the test temperatures and loading rates. This fact indicates that the PP has typical viscoelastic properties. The creep behavior was evaluated by Norton's law, which indicated that the stress exponent is independent for test temperature.
