Cellulose nanofibrils prepared by twin-screw extrusion: Effect of the fiber pretreatment on the fibrillation efficiency. (15th July 2020)

• Record Type: Journal Article
• Authors: Trigui, Khadija; De Loubens, Clément; Magnin, Albert; Putaux, Jean-Luc; Boufi, Sami
• Is Part Of: Carbohydrate polymers. Volume 240(2020)
• Publication Date: 2020-07-15
• Subjects: Cellulose nanofibrils -- Oxidation -- Twin-Screw extrusion; Polysaccharides -- Periodicals; Polysaccharides -- Periodicals; Polysaccharides -- Périodiques; Electronic journals; 547.78
• DOI: 10.1016/j.carbpol.2020.116342
• Languages: English
• ISSNs: 0144-8617

Abstract

Highlights: Cellulose nanofibrils from eucalyptus pulp were produced by twin-screw extrusion (TSE) A chemical pretreatment by oxidation or carboxymethylation was necessary for the TSE. The chemical pretreatment strongly affects the swelling degree of the fibers The TSE contributed to facilitate the production of CNFs at a high solid content Abstract: Twin-screw extrusion (TSE) is a rather recent method to produce cellulose nanofibrils (CNFs) at a high solid content under continuous feeding. Here, never-dried commercial eucalyptus pulp was used as starting material to produce CNFs by TSE after a chemical pretreatment to introduce carboxylic groups via TEMPO-mediated oxidation and carboxymethylation. Five samples with a carboxyl content ranging from 800 to 1300 μmol.g −1 were produced to explore how the carboxyl content affects the aptitude of cellulose fibers to be broken down to nanoscale. The properties of the resulting CNFs in terms of nanosized fraction, morphology and rheological properties were investigated. A critical carboxyl content of 700 μmol.g −1 was a prerequisite for the successful conversion of cellulose fibers into a CNF gel by TSE, regardless the pretreatment method. The degree of swelling of the fibers was put forward to account for this critical parameter.