Medical Design Briefs - May 2024 - 29

cess can occur at room temperature, but
it can also be sped up using heat.
Manufacturing
processes
involving
elastomers have typically relied on empirical
estimates for temperature and duration
to control the curing process. However,
this ballpark approach makes it
difficult to predict how elastomers will
behave under varying curing conditions.
Having a quantitative framework to determine
exactly how temperature impacts
curing speed will enable manufacturers
to maximize efficiency and reduce waste.
" Previously, using existing models to
predict elastomers' curing behavior under
varying temperature conditions was a
much more challenging task, " says Te
Faye Yap, a graduate student in the Preston
lab who is lead author on the study.
" There's a huge need to make manufacturing
processes more efficient and reduce
waste, both in terms of energy consumption
and materials. "
To understand how temperature impacts
the curing process, the researchers
used a rheometer - an instrument that
measures the mechanical properties of
liquids and soft solids - to analyze the
curing behavior of six commercially
available platinum-catalyzed elastomers.
" We were able to develop a model
based on what is called the Arrhenius relationship
that relates this curing reaction
rate to the temperature at which the
elastomer is being cured, " Preston says.
" Now we have a really nice quantitative
understanding of exactly how temperature
impacts curing speed. "
The Arrhenius framework, a formula
that relates the rate of chemical reactions
to temperature, has been used in a variety
of contexts such as semiconductor processing
and virus inactivation. Preston and his
group have used the framework in some of
their prior work and found it also applies to
curing reactions for materials like epoxies
as described in previous studies. In this
study, the researchers used the Arrhenius
framework along with rheological data to
develop an analytical model that could directly
impact manufacturing practices.
" In this work, we really probed the
curing reaction as a function of the temperature
of the elastomer, but we also
looked in depth at the mechanical properties
of the elastomers when cured at
elevated temperatures meant to achieve
these higher throughputs and curing
speeds, " Preston says.
Te Faye Yap, a Rice University PhD student in the Preston lab and lead author on a study published in Cell Reports
Physical Science, demonstrates the performance of grippers cured at room temperature (blue) and at elevated
temperatures (red) when pressurized. (Credit: Jeff Fitlow/Rice University)
The researchers conducted mechanical
testing on elastomer samples that were
cured at room temperature and at elevated
temperatures to see whether heating
treatments impact the materials' mechanical
properties.
" We found that exposing the elastomers
to 70 °C (158 °F) does not alter the tensile
and compressive properties of the material
when compared to components that were
cured at room temperature, " Yap says.
" Moreover, to demonstrate the usage of
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Te Faye Yap (left) and Daniel Preston. (Credit: Jeff Fitlow/Rice University)
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Medical Design Briefs - May 2024

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