Graft modification of cellulose nanocrystals via nitroxide-mediated polymerisation

Cellulose nanocrystals (CNC) have become the subject of increasing research interest because of their unique physical, chemical and mechanical properties, including being a renewable material. While CNC shows promise as a reinforcing material in polymer-based composites, the hydrophilic surface of CNC makes dispersibility in most hydrophobic polymers very difficult which limits potential applications. In this study, we report the first graft modification of CNC using nitroxide-mediated radical polymerisation. The CNC surface was first functionalised with the nitroxide SG1 (4-(diethoxyphosphinyl)-2,2,5,5-tetramethyl-3-azahexane-N-oxyl), yielding a CNC-macroalkoxyamine. Poly(methyl acrylate) and poly(methyl methacrylate) chains were then grafted from the CNC-macroalkoxyamine surface to yield polymer graft modified CNC.