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Viscoelasticity in carbon nanotube composites
Jonghwan Suhr1, Nikhil Koratkar, Pawel Keblinski
1Department of Mechanical, Aerospace and Nuclear Engineering, Rensselaer Polytechnic Institute, Troy, New York 12180, USA.
Nature Materials
|January 11, 2005
Summary
Carbon nanotube polymer composites show enhanced damping without sacrificing strength. Interfacial sliding between nanotubes in epoxy films dissipates energy, significantly increasing mechanical damping.
Area of Science:
- Materials Science
- Polymer Science
- Nanotechnology
Background:
- Polymer composites reinforced by carbon nanotubes are researched for strength and stiffness.
- Poor load transfer at interfaces can lead to slippage and reduced performance.
- Interfacial shear, while detrimental to stiffness, can enhance mechanical damping.
Purpose of the Study:
- To investigate the damping properties of epoxy thin films with dense multiwalled carbon nanotube fillers.
- To directly measure interfacial shear behavior and its effect on viscoelasticity.
- To explore the potential for high damping in nanocomposites without compromising mechanical properties.
Main Methods:
- Direct shear testing of epoxy thin films containing multiwalled carbon nanotubes.
- Measurement of modal response at resonance for cantilevered beams with nanocomposite films.
- Analysis of viscoelastic behavior and loss factor increase.
Main Results:
- Demonstrated strong viscoelastic behavior in carbon nanotube-filled epoxy films.
- Achieved up to a 1,400% increase in the loss factor (damping ratio) compared to baseline epoxy.
- Maintained mechanical strength and stiffness with minimal weight increase.
Conclusions:
- The enhanced damping is attributed to frictional energy dissipation during interfacial sliding.
- Damping is linked to nanotube-nanotube interfaces at specific interfacial shear stress levels.
- This approach offers a method to significantly improve damping in polymer composites.