Cellulose nanofibres by sonocatalysed-TEMPO-oxidation

The purpose of this work was to study the influence of acoustic cavitation on the oxidation of a mill bleached machine dried hardwood Kraft pulp. The oxidation of the pulp was carried out using 4-acetamido-TEMPO coupled with NaOCl/NaBr as co-oxidizer. The carboxylate content was increased by about 30% without any adverse impact on the degree of polymerization in the case of oxidations under acoustic cavitation compared to the reference without acoustic cavitation. A close correlation between the yield of nanocellulose and the carboxylate content of the oxidized pulps was observed. The individualized cellulose nanofibres were 3-4 nm in width and a few microns in length.