Enhancing the Oxygen-Barrier Properties of Polylactide by Tailoring the Arrangement of Crystalline Lamellae

The gas-barrier properties of semicrystalline polymers can be significantly adjusted by tailoring the arrangement of their impermeable crystalline lamellae. In particular, the highest barrier efficiency is achieved when the arrangement of the lamellae stacks is perpendicular to the direction of gas diffusion. The work reported on in this paper provides a strategy to achieve such a lamellar arrangement with the aid of a self-assembly nucleator and a two-dimensional (2D) interface. PT (PLA + TMC-300) and PTG (PLA + TMC-300 + graphene) were coextruded to form alternating PT/PTG multilayers with different layer numbers. During isothermal treatment at 140 °C, the dissolved TMC-300 first self-assembles into solid-state fibrils that are perpendicular to the 2D PT/PTG-layered interface due to the induced effects of the graphene. Subsequently, these TMC-300 fibrils induce the epitaxial growth of PLA lamellae with a normal parallel to the fibrillar direction of the TMC-300. In this way, a designed arrangement where...