Viscoelastic response of high volume fraction carbon nanotube-polymer nanocomposites with tailored wettability and controlled morphology

Official URL: http://dx.doi.org/10.1016/j.compstruct.2018.10.007

As-grown VACNTs are subjected to mechanical densification by knock-down process to achieve higher volume fractions. In here, the preferential alignment of CNTs is preserved horizontally and an easy delamination of VACNTs are achieved to fabricate high volume fraction nanocomposites. Both physical and chemical properties of VACNTs such as alignment, quality, and purity etc. have been characterized by Raman spectroscopy, TGA, and SEM. The knocked-down VACNTs arrays are then used as ‘reinforcing ply’ with epoxy for PNCs fabrication. Since load transfer in between CNTs and epoxy is important to avoid interfacial slippage and reduction in loss factor, to increase interaction between CNTs and epoxy, ozone treatment was applied to CNTs. To observe the effect of ozone treatment on the viscoelastic response of polymer nanocomposites with non-ozone treated and ozone treated VACNT were tested by DMA under different frequencies. The ozone treatment time and CNT quality, investigated through Raman Spectroscopy, were correlated for viscoelastic properties. The results demonstrated that ozone treatment improved wettability and increased viscoelastic properties of PNCs under multi-frequency for short-term (<60 s) but resulted in a decrease in storage modulus when applied for in longer durations.