Cellulose is one of the most abundant macromolecules on the planet found in plants, sea creatures and some species of bacteria. By using controlled acid hydrolysis it is possible to isolate highly crystalline rod like crystals or Cellulose Nanocrystals (CNs). They possess many desirable characteristics for nano-fillers such as being non-toxic, biodegradable, low density, and a highly reactive surface.The most common method to make CNs uses either sulfuric acid or hydrochloric acid hydrolysis. Use of the latter results in CNs that when dried are irreversibly aggregated due to formation of a strong hydrogen bonding network. Surface modification of CNs can prevent this aggregation phenomenon upon drying.Recently, a green one-step approach based on concurrent Fischer Esterification with an organic acid and acid hydrolysis occur resulting in functionalized ready-to-use CNs. This presentation reports the development of one-step methods to prepare CNs decorated with free carboxylic acid moieties by esterification with citric, malonic and malic acids as shown in figure 1. The concentration of hydrochloric acid in mixtures with the above organic acids was varied and optimal amounts of hydrochloric acid were determined. Residual unhydrolyzed cellulose was then subjected to further hydrolysis reactions to generate additional CNs to increase the yield. The modified CNs were characterized by FTIR, NMR, contact angle, SEM, and XRD.

Cellulose nanocrystals decorated with free carboxylic acids by one step hydrolysis/Fischer esterification reactions

248th National Meeting (2014)

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