University of Sfax- LMSE-Faculty of Science-BP 802-3018Sfax, Tunisia.
Univ. Grenoble Alpes, CNRS, Grenoble INP, LRP, F-38000 Grenoble, France.
Carbohydr Polym. 2020 Jul 15;240:116342. doi: 10.1016/j.carbpol.2020.116342. Epub 2020 May 1.
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 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.gwas 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.
双螺杆挤出（TSE）是一种较新的方法，可以在连续进料的情况下，在高固含量下生产纤维素纳米纤维（CNF）。在这里，从未干燥的商业桉树浆粕用作起始材料，通过 TEMPO 介导的氧化和羧甲基化引入羧基基团的化学预处理，通过 TSE 生产 CNF。制备了五个羧基含量范围为 800 到 1300 μmol.g 的样品，以探索羧基含量如何影响纤维素纤维分解为纳米级的能力。研究了所得 CNF 的纳米级部分、形态和流变性能的性质。无论预处理方法如何，对于通过 TSE 将纤维素纤维成功转化为 CNF 凝胶而言，700 μmol.g 的临界羧基含量是必要的。提出纤维的溶胀度来解释这个关键参数。
