High Content Microfibrillated Cellulose Suspensions Produced from Deep Eutectic Solvents Treated Fibres Using Twin-Screw Extruder
Résumé
In this study, cellulosic fibres (bleached Kraft pulp of Eucalyptus), pre-treated with Deep Eutectic Solvents (DES), have been microfibrillated using a twin-screw extruder (TSE). DES pre-treatment was performed for 4 h at 100 °C with three eutectic systems: betaine hydrochloride–urea, choline chloride–urea and choline chloride–monoethanolamine. DES-treated fibres were first refined (PFI-mill) and then passed four times through the TSE whose advantage is to obtain microfibrillated cellulose (MFC) at high solid content (20%). Several characterisations were carried out before and after TSE to evaluate the effects of these treatments on both the fibres and MFC. The Young’s modulus of the obtained nanopapers was, for instance, around 6 GPa. Extruded-MFC were compared to those produced by ultrafine grinding. The comparison showed that the ultrafine grinding allows obtaining MFC of better quality. This result can be attributed to the slipping phenomenon occurred during extrusion.