Probing deformation of double-walled carbon nanotube (DWNT)/epoxy composites using FTIR and Raman techniques

• Published in: Composites science and technology Vol. 70; no. 10; pp. 1460 - 1468
• Main Authors: Brownlow, Scott R., Moravsky, Alexander P., Kalugin, Nikolai G., Majumdar, Bhaskar S.
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 30-09-2010; Elsevier
• Subjects: A. Carbon nanotubes; A. Nano composites; Applied sciences; C. Stress transfer; Carbon nanotubes; Composites; D. Infrared (IR) spectroscopy; D. Raman spectroscopy; Exact sciences and technology; Forms of application and semi-finished materials; Nanostructure; Nanotubes; Particulate composites; Polymer industry, paints, wood; Polymer matrix composites; Stress transfer; Stresses; Technology of polymers; Tensile stress; C. Stress transfer; D. Raman spectroscopy; A. Nano composites; A. Carbon nanotubes; D. Infrared (IR) spectroscopy; Mat; Stress analysis; Laminate; Epoxy resin; Carbon nanotubes; Mechanical properties; Dispersion reinforced material; Tensile property; Curing (plastics); Experimental study; Mineral fiber; Composite material; Optical measurement; Concentration effect; Nanocomposite; Infrared spectrum; Raman spectrum
• ISSN: 0266-3538; 1879-1050
• DOI: 10.1016/j.compscitech.2010.04.025

Two of the limitations of carbon nanotube (CNT) polymer composites have been the low volume fraction of nanotubes and inadequate load transfer from the polymer to the stiff CNT. Here, we have utilized functionalized mats of double-walled nanotubes (DWNT) to obtain 10
wt.% DWNT in an epoxy matrix, with strength approaching those of quasi-isotropic carbon fiber composites. We used the transmission FTIR technique with
in situ loaded specimens to monitor spectral shift per unit applied stress for understanding load transfer behavior at the nanotube–epoxy interface. Tests show that in most cases a tensile stress causes negative FTIR peak shift in the neat epoxy, but this behavior is not always observed for the epoxy matrix in the composite. The FTIR data can be used successfully to estimate the average matrix stress in the composite and thereby the average stress in the nanotubes.
In situ Raman studies using the
G′ peak are also conducted to obtain complementary information on average tensile stress in the DWNT in the loading direction. The shift response is found to be ∼37
cm
−1/GPa.