Fibrillation of Cellulosic Pulps Facilitated by Hydroxycinnamic Acids

High Resolution Image Download MS PowerPoint Slide This study reports the impact of hydroxycinnamic acid functionalization of cellulosic pulps as a strategy to facilitate fibrillation. We studied the effect of three hydroxycinnamic acids, cinnamic acid, coumaric acid, and ferulic acid, on different cellulosic pulps. Reactions were performed in isopropanol media at 70 °C for 1 h. Grafting of hydroxycinnamic acids was evidenced by FTIR and a slight increase in surface charge. Functionalization with hydroxycinnamic acids did not increase the surface charge to a great extent compared to 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) oxidation or carboxymethylation. Nevertheless, the reaction significantly reduced the fiber width and facilitated fibrillation under magnetic stirring. Functionalization with hydroxycinnamic acids did not change the chemical composition of cellulosic pulps, and the molar masses were not significantly impacted, which suggested that hydroxycinnamic acids intercalated between the cellulose fibrils, facilitating their further separation but not their immediate disruption. The functionalization strategy is promising since the reaction occurs under mild conditions (70 °C for 1 h) and does not involve toxic chemicals, and the fiber structural patterns (composition, fiber length, degree of polymerization) are maintained while achieving fibrillation.