Super Strong All-Cellulose Composite Filaments by Combination of Inducing Nanofiber Formation and Adding Nanofibrillated Cellulose.

In this work, super strong all-cellulose multifilaments were obtained from cellulose dissolved in LiOH/urea system by inducing nanofiber formation, and were simultaneously reinforced by the introduction of TEMPO-oxidized nanofibrillated cellulose (NFC) with mean diameter of 20 nm. The all-cellulose composite filaments (CF) containing only 3 wt % NFC exhibits a high orientation that Herman's parameter is 0.89. Importantly, the NFC can simultaneously reinforce and toughen the CF, with a tensile strength and elongation at break of 3.92 cN/dT and 14.6%, respectively, which make the obtained CF to become super strong. The strengthened mechanism of CF is considered as the nanofibril-induced crystallization and orientation, which makes up for the deficits and constructs a flawless structure in the regenerated cellulose filaments. Of note, the stability of spinning dope was also effectively improved by adding small amount of NFC, which is very important for fiber spinning on industry. This finding contributes to the preparation of high performance regenerated cellulose multifilaments by a simple, energy-efficient, and eco-friendly route.

Self-recovery magnetic hydrogel with high strength and toughness using nanofibrillated cellulose as a dispersing agent and filler.

Fe3O4 nanocomposite hydrogels, with intrinsic magnetism, can be potentially applied in extensive fields. However, the poor mechanical properties and complex fabrication processes of conventional magnetic hydrogels seriously limit their advanced applications. Herein, this work demonstrates an efficient and easily industrialized method to prepare self-recovery magnetic hydrogels with excellent mechanical performances. In this method, Fe3O4 nanoparticles were facilely dispersed in polyacrylamide (PAM) hydrogels with the assistance of nanofibrillated cellulose (NFC), resulting in good magnetism. The tensile strength and elongation at break of hydrogels increase from 150 to 780 KPa, 1400% to 2960%, respectively, due to the unique network structure and the strong hydrogen bonding interaction between NFC and PAM. Moreover, the obtained hydrogels possess the satisfactory self-recovery ability, thermal stability, and shear resistance. We believe this efficient and simple method can expand the application of high-performance composite hydrogels in biological, medical and environmental fields.