Alkylation of Nanocellulose for the improvement of dispersion in the polymer matrix

Abstract

Nanocellulose tends to be aggregated due to the hydrogen bonding between three of the hydroxyl groups in each repeating unit, resulting in poor dispersion in the non-polar polymer matrix. In this research, to improve the dispersion of nanocellulose particles in the polymer matrix, a long hydrophobic alkyl chain was substituted for hydrogen in the hydroxyl group of nanocellulose via a bimolecular nucleophilic substitution (SN2) reaction with alkyl bromide. The octyl (-C8H17) and dodecyl (-C12H25) groups were applied to this reaction, which is faster and simpler compared to other substitution reactions. The chemical structure of octyl and dodecyl nanocellulose was identified by the Fourier transform infrared (FT-IR) and nuclear magnetic resonance (NMR) analysis. The contact angle with water and methylene iodide was measured to calculate the surface energy of alkyl nanocellulose. The surface energy was decreased by the substituted alkyl chain. The thermal properties, morphology and crystal structure of octyl and dodecyl nanocellulose were also investigated to qualify the probability as a reinforcement.