Model Development for Nanotube-Infused Polyimides
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Date
2009-08-07
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Abstract
Polyimides are a class of polymers that are thermally and chemically stable and radiation
resistant. In addition to their stability, polyimides possess a relatively large elastic modulus and
are flexible. Their stability and stiffness make them good candidates for use in space applications.
However, due to their insulating nature, static charge build-up can deteriorate the structure. This
charge build-up can be mitigated by embedding single-wall nanotubes (SWNTs) into the polyimide.
SWNTs are excellent conductors and have a high elastic modulus. Thus, embedding the SWNTs
into the polyimide not only introduces conductivity but also increases the stiffness of the composite.
SWNTs can also be added to create an active structure from inactive polyimides.
Nanocomposites are being investigated for use in constructing large ultra-lightweight
(gossamer) spacecraft. Since the gossamer spacecraft is folded and packed into the launch vehi-
cle prior to launch, the materials need to withstand this process. The nanotube-infused polyimides
are flexible enough to withstand the packaging process and strong enough to withstand the harsh
space environment. Speciﬠc applications of the gossamer spacecraft include thin-ﬠlm membrane
mirrors and gossamer antennas.
Nanotube composites have been modeled in the past using a variety of techniques. How-
ever, much of the previous work focused on modeling the elastic modulus at a set temperature.
Since temperatures widely vary in space, a temperature-dependent model is required for the elastic
modulus.
In this work, we present a temperature-dependent continuum material model, based on
phenomenological elasticity theory, which characterizes stiffness through the material as a func-
tion of varying concentrations of nano-inclusions. Attributes of the model are illustrated through
comparison with experimental data for the polyimide (β -CN)-APB/ODPA and LARC-CP2. In
Chapters 5 and 6, system models are developed and implemented for 1D and 2D nanotube-infused
membranes under tension.
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Keywords
single wall nanotubes, polyimides, carbon nanotubes
Citation
Degree
PhD
Discipline
Applied Mathematics
