Stable graphene-nanocellulose dispersions for future composite materials

Important results from the project

Aim: Dispersing graphene in water using nanocellulose. Goal (A) maximizing the graphene amount relative to the nanocellulose amount. (B) Maximizing the dry content of graphene, (C) appropriate rheological properties for coating, (D) increased knowledge about graphene nanocellulose interactions. The main efforts were dedicated on goal D, as that governs goal A and B, as well as goal C. For both goals significant knowledge was gained, which will be valuable in order to optimize the production of dispersions, coatings, composites of graphene nanocellulose mixtures.

Expected long term effects

Interaction between graphene and nanocellulose were shown by clear adsorption of nanocellulose on the graphene surface by AFM, as well as stabilizing/dispersing graphene in nanocellulose dispersions below the network concentration. The formed hybrid thermaly degraded in-between the individual components, and the stability of the nanocellulose was affected (decreased) by the graphene addition. Even though the dispersion stability was insufficient, the shown interaction could enable the development of stable G-NC dispersions, interesting for both coatings and composites.

Approach and implementation

The study was a collaboration between RISE and BillerudKorsnäs. It started with a literature survey, followed by an experimental study: Graphene was dispersed in water using different nanocelluloses (varied charge density/type) by sonication, followed by fractionation by centrifugation. The co-dispersions were characterized using UV-vis, TGA, DLS, RAMAN and AFM, as well as evaluating the colloidal stability as a function of salt and acid. Focus was on the interactions in order to understand how to optimize; dispersion properties, and the production of coatings and composites.