Influence of carbon nanotube waviness on the stiffness reduction of CNT/polymer composites

The degree to which the non-straight shape of carbon nanotube (CNT) affects the mechanical properties of CNT-based composites is studied. The effective scale of CNT curvature is determined using top-down scanning and then appropriate representative volume element encompassing of several straight and/or non-straight CNTs is defined. A multi-scale modeling relying on bottom-up approach is employed and CNT curvature is taken into account as a random parameter to capture any arbitrary non-straight shapes of CNTs. Comparing obtained results from developed modeling with available experimental data, the developed modeling procedure is validated. The results demonstrate that non-straight shape of CNT considerably reduces its efficiency to reinforce polymer matrix. It is observed that low contents of CNT enhance Young’s modulus of polymer more efficiently due to the lower level of CNT waviness and agglomeration. The results exhibit non-linear variations in the Young’s modulus of CNT-based composites versus CNT contents which was approved by experimental observations.