effect (see Figure 31)
is actually two related phenomena. First, unlike
many materials, rubber heats up when stretched
quickly. Second, rubber that is held stationary
at one end and stretched under a given load will
actually retract if localized heat is applied.
This is true because the rubber’s stressed macromolecular chains
are trying to regain a less-stressful state.
The Gough-Joule effect is perhaps most important
seal designs, where excessive installed
stretch in conjunction with system heat can
cause an O-ring to retract, seizing the rapidly
rotating shaft and
dooming the design.
these physical, chemical,
properties in mind, let’s now look
more specifically at the relative strengths and
weaknesses of the most commonly used O-ring materials.
PROPERTIES MAIN PAGE
O-rings often face extreme heat or extreme cold, there are important thermal properties
you must consider.”