The modification of cellulose through polymer grafting has been of interest for many years. Typically, chains are grafted, either via grafting-to of preformed polymer chains, or via grafting-from, where the polymerization is initiated from the surface.1 Another approach to cellulose modification is to physically adsorb polymers onto the fiber surface. Amphiphilic block copolymers, composed of a cationic polyelectrolyte and a hydrophobic polymer block, easily prepared employing ATRP in combination with Ring Opening-Polymerization (ROP), can be adsorbed onto cellulose surface under aqueous conditions.2,3 Herein, covalent grafting and physical adsorption have been compared for the first time, with respect to the material properties of nanocomposites. The nanocomposites were prepared using PCL as matrix and cellulose nanofibrils (CNF) as reinforcing element. The CNF had previously been modified with PCL either through grafting-from by surface-initiated ROP of ε-CL or by physically adsorbing a polymer of quaternized PDMAEMA-block-PCL. Evaluation of the final bionanocomposites revealed that modification by physical adsorption resulted in a strong but brittle material, while modification by covalent grafting resulted in a tougher material. E. Malmström, A. Carlmark, Polymer Chemistry, 2012, 3 (7), 1702 – 1713. S. Utsel, L. Wågberg el al. ACS Appl. Mater. Inter. 2012, 4, 6796. A. Carlmark, Macromol. Chem. Phys. 2013, 214(14), 1539-1544. S. Hansson, et al. Biomacromolecules 2013, 14(1), 64-74

Polymer-grafting or adsorption of amphiphilic block copolymers - different approaches to compatibilization in CNF-based nanocomposites

249th National Meeting (2015)

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