Influence of multiwall carbon nanotube alignment on vibration damping of nanocomposites

In the present work, the damping behavior of multiwall carbon nanotubes/polymer nanocomposites has been studied by aligning the carbon nanotubes (CNTs) in the matrix using DC electric field during the curing of composite. Nanocomposite specimens have been fabricated for three different CNT loadings (0.1, 0.2, and 0.3wt%) to prepare two types, namely randomly oriented and aligned. The alignment of nanocomposites has developed a strong anisotropy in the composite. Microstructural analysis and electrical conductivity tests are carried out to examine the CNTs alignment. It is evident from the obtained results that a significant improvement is achieved in electrical conductivity of aligned nanocomposites over randomly oriented one. Dynamic mechanical analysis and flexural vibration experiments have been performed to study the frequency dependent damping behavior of nanocomposites. In case of aligned nanocomposites, significant enhancement is noticed in the material damping for the tested frequency band width of 0-30Hz; also the flexural tests have shown an improvement up to 37% in structural damping compared to randomly oriented. The influence of CNT coating on fiber in improving anisotropic nature of fiber has been studied experimentally and it is found that the coating of CNT reinforced resin has enhanced simultaneously the straining capability and anisotropic nature of the fiber, without compromising its mechanical properties. Further, the vibration damping behavior of the CNT coated fiber is evaluated using digital image correlation technique and it is noticed that CNT dispersion on the fiber improves its damping ability by 2.6%.