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Effect of Nanotube Functionalization on the Coefficient of Thermal Expansion of Nanocomposites

Authors

  • S. Wang,

    1. Department of Industrial & Manufacturing Engineering, High-Performance Materials Institute, FAMU-FSU College of Engineering, Florida State University, 2525 Pottsdamer Street, Tallahassee, FL 32310-6046, USA
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  • Z. Liang,

    1. Department of Industrial & Manufacturing Engineering, High-Performance Materials Institute, FAMU-FSU College of Engineering, Florida State University, 2525 Pottsdamer Street, Tallahassee, FL 32310-6046, USA
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  • P. Gonnet,

    1. Department of Industrial & Manufacturing Engineering, High-Performance Materials Institute, FAMU-FSU College of Engineering, Florida State University, 2525 Pottsdamer Street, Tallahassee, FL 32310-6046, USA
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  • Y.-H. Liao,

    1. Department of Industrial & Manufacturing Engineering, High-Performance Materials Institute, FAMU-FSU College of Engineering, Florida State University, 2525 Pottsdamer Street, Tallahassee, FL 32310-6046, USA
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  • B. Wang,

    1. Department of Industrial & Manufacturing Engineering, High-Performance Materials Institute, FAMU-FSU College of Engineering, Florida State University, 2525 Pottsdamer Street, Tallahassee, FL 32310-6046, USA
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  • C. Zhang

    1. Department of Industrial & Manufacturing Engineering, High-Performance Materials Institute, FAMU-FSU College of Engineering, Florida State University, 2525 Pottsdamer Street, Tallahassee, FL 32310-6046, USA
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  • This work was partially supported by the Army Research Laboratory NOLES program. The authors would like to thank Mr. Walter Roy and Dr. Shawn Walsh for their support and management of this project. This research was also supported by AFOSR grant no. FA9550-05-1-0271. The management of this program by Dr. Charles Lee is greatly appreciated. The Cornerstone Program of the FSU Research Foundation also provided support for this project.

Abstract

Single-walled carbon nanotubes (SWNTs) are functionalized through both covalent and noncovalent bonding approaches to enhance dispersion and interfacial bonding. The coefficient of thermal expansion (CTE) of the functionalized-SWNT-reinforced epoxy composites are measured with a thermal mechanical analyzer (TMA). Experimental results indicate that changes of the glass-transition temperature (Tg) in functionalized SWNT–polymer composites are dependent upon the functionalization methods. The CTE below the glass-transition temperature of nanocomposites with a 1 wt % loading of nanotubes is substantially diminished compared to a neat polymer. A reduction in the CTE of up to 52 % is observed for nanocomposites using functionalized nanotubes. However, the CTE above the Tg significantly increases because of the contribution from phonon mode and Brownian motions of a large number of SWNTs in resin-crosslinked networks, but the increments are compromised by possible interfacial confinement. A tunable CTE induced through nanotube functionalization has application potentials for high-performance composites, intelligent materials, and circuit protections.

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