Dry processing and recycling of thick nacre–mimetic nanocomposites

Abstract

Bioinspired nanocomposites with high levels of reinforcement hold great promise for future, green lightweight, and functional engineering materials, but they suffer from slow, tedious, and nonscalable preparation routes, that typically only lead to very thin films. A rapid and facile dry powder processing technique is introduced to generate bioinspired nanocomposite materials at high fractions of reinforcements (50 wt%) and with millimeter scale thickness. The process uses powder drying of vitrimer-coated nanoplatelets (nanoclay and MXene) from aqueous solution and subsequent hot-pressing. As a method of choice in industrial lightweight composite materials engineering, hot-pressing underscores a high potential to translate this approach to actual products. The use of the vitrimer chemistry with temperature-activated bond shuffling is important to facilitate smooth integration into the nanocomposite design, leading to layered nacre-inspired nanocomposites with nanoscale hard/soft order traced by X-ray diffraction and excellent mechanical properties investigated using flexural tests. Recycling by grinding and hot-pressing is possible without property loss. The compatibility with existing composite processing techniques, scalable thickness and dimensions, and recyclability open considerable opportunities for translating bioinspired nanocomposites to real-life applications.