Simultaneously Boosting Toughness and Tensile Strength for Polyamide 6/montmorillonite Nanocomposite by a Pressure-Induced Flow Field

Nanocomposites of polymers and montmorillonite (MMT) represent a type of important hybrid material. However, unlike in some natural hybrid materials where much improved mechanical properties are achieved by an ordered assembly (layered, sheet-like or fibrous morphology) of complementary hard and soft components on nano- and microscopic scales, the exfoliated MMT nano-sheets are generally randomly dispersed in bulk polymeric matrices. In this paper we utilized a pressure-induced flow (PIF) field to orient MMT nano-sheets and generate stratified morphologies in polyamide 6 (PA6)/MMT nanocomposite bulk material. The toughness and tensile strength can be simultaneously increased. In particular, the impact strength increased up to 10 fold higher than the same material obtained by conventional processing methods. The mechanism for enhancement could be the confinement of crack propagations and the tortuous energy dissipating paths, which are attributed to the oriented MMT and the anisotropic hierarchical morphologies formed during PIF-processing.