Extensional flow-induced hybrid crystalline fibrils (shish) in CNT/PLA nanocomposite

Abstract The formation of a hybrid crystalline fibrils (shish), in which the carbon nanotubes (CNTs) are coated by polymer extended chain, is an effective route to couple polymers and CNTs together but needs extreme conditions like fiber spinning or stirring CNT/polymer solution. In this work, both the hybrid shish and homogeneous shish have been achieved in the extruded sheets of poly ( l -lactic acid) (PLA)/CNT nanocomposite, via the multistage stretching extrusion, in which fishtail channels were connected in series to produce an intense extensional flow. Compared with the conventional CNT/PLA nanocomposite, the CNT/PLA nanocomposite with shish shows dramatic increment on elongation at break (502%), strength (31%) and modulus (53%). And this can be ascribed to the alignment CNTs, the robust interfacial adhesion generated via CNTs coated by PLA crystalline phase and the enhanced properties of PLA matrix achieved by introducing the homogeneous crystalline fibrils (shish). Without any chemical treatment, only by tailoring the crystalline microstructure, the nanocomposite shows outstanding performances. Consequently, this work is potentially useful to dramatically improve the performances of nanocomposites with industrial feasibility.