Production of lignin-containing cellulose nanofibers using deep eutectic solvents for UV-absorbing polymer reinforcement

Lignin-containing cellulose nanofibers (LCNFs) from energy cane bagasse (ECB), were prepared using microwave assisted deep eutectic solvent (MV-DES) treatment in combination with ultrasonication. The yield of lignocellulose is up to 45.2 % with 81.0 % delignification under the optimal reaction condition (110 ℃, 30 min). The resulting LCNF exhibited a highly entangled network, which was caused by the binder role of lignin between cellulose nanofibers. The addition of LCNFs improved the stability of the polyanionic cellulose (PAC) film-forming suspension, which was confirmed by the increased zeta potential and viscosity values. The LCNF / PAC films showed tunable mechanical and UV-resistant properties, depending on the amount and type of LCNFs. PAC films with the addition of 5 % LCNFs (PEF-5 %) showed good mechanical properties (a tensile strength of 55.8 MPa with a 26.3 % strain to break) and high UV protection ability (a UV-transmittance of 2.9 %).