Meaning
Materials scientists use a sequence of short-term creep tests at increasing aging times to measure how physical aging shifts the relaxation times of glassy polymers. This method of testing and modeling is known as struik aging, which establishes how the mechanical spectrum of a polymer moves toward longer times as it relaxes below its glass transition temperature. It defines the boundary where the aging rate remains constant, allowing engineers to predict long-term material behavior from short-term tests.
This protocol is the foundation of physical aging studies.
Time Translation
The core principle of this theory is that physical aging simply shifts the material’s timescale without changing the shape of the relaxation curve. In a struik aging test, the shift factor relates the relaxation time of an aged sample to its unaged state. This relationship is modeled using a power-law shift rate that is constant over a wide range of temperatures.
This allows for the acceleration of material evaluations.
Experimental Execution
The protocol requires running sequential creep tests where the duration of each test is much shorter than the elapsed aging time. This prevents the test itself from altering the aging state. It maintains the accuracy of the measurements.
Component Design
Understanding this behavior helps engineers design plastic parts that must withstand continuous loads for years. This modeling ensures that parts do not fail prematurely due to stiffness changes.
