In this blog post, we discuss the 10-degree rule as a quick estimation for product life time.
Polymer
materials are more and more used as protection and as barriers towards harsh
and aggressive chemicals. As already previously discussed, plastic part failure
is linked to phenomenological and human causes such as material misselection
and poor specification. To prevent part failure, an increased focus on material selection is beneficial. In material selection, especially in the practical
validation tests, estimation of part lifetime is needed. If the part
specification states that the part lifetime needs to be 3,000 hours, the
selected polymer needs to be checked for suitability.
Here
comes the 10-degree rule into the game. The 10-degree rule, also called the Q10
rule, the RGT-rule (ReaktionsGeschwindigkeit-Temperatur-rule), or Van’t Hoff’s
rule, states that the polymer thermal aging rate k is doubled for every
temperature delta of 10°C. It is based on the Arrhenius relationship, which
shows the temperature dependence of reaction rates.
 |
| The 10-degree rule, also called the Q10 rule. |
Also, more common written as:
Accelerating part testing by increasing temperature
In
essence, the 10-degree rule says that for every 10°C increase, the reaction
rates double. As a consequence, the useful life time of the material will be halved.
Since it is an exponential function, test temperature changes of for example 50°C
will result in reaction time changes by factor 32.
In
practical terms, it means instead of testing at room temperature (25°C),
increasing the test temperature in 10°C steps will accelerate testing
enormously. Furthermore, extrapolation to longer times is possible.
One
last remark: the 10-degree rule is a purely phenomenological rule and the
predictive character is limited.
Thanks
for reading and #findoutaboutplastics
Greetings,
Herwig Juster
Interested to talk with me about your polymer material selection, sustainability, and part design needs - here you can contact me
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Literature:
[2] https://www.ptonline.com/articles/materials-the-mystery-of-physical-aging-part-3
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