Preparation of sodium cellulose sulfate oligomers by free-radical depolymerization

Preparation and characterization of sulfated nanocellulose: From hydrogels to highly transparent films

This study focuses on the production of sulfated cellulose microfibers and nanocellulose hydrogels from native cellulose microfibers (CMF). The process involves using a combination of H2SO4 and urea, resulting in highly sulfated cellulose microfiber hydrogel (SC) with notable properties such as a sulfur content of 7.5 %, a degree of sulfation of 0.49, a surface charge content of 2.2 mmol. g-1, and a high yield of 81 %. The SC hydrogel can be easily fibrillated into sulfated nanocellulose hydrogel (S-NC) with elongated nanocellulose structures having an average diameter of 6.85 ± 3.11 nm, as determined using atomic force microscopy (AFM). X-ray photoelectron spectroscopy (XPS) analysis confirms the presence of sulfate groups on the surface of the nanocellulose material. Transparent films with good mechanical properties can be produced from both cellulose microfiber and nanocellulose hydrogels. The sulfate functionality gives the hydrogel attractive rheological properties and makes S-NC re-dispersible in water, which can be beneficial for various applications. This study demonstrates the potential of this process to address previous challenges related to nanocellulose materials production.

Cellulose sulfate lithium as a conductive binder for LiFePO4 cathode with long cycle life

Polysaccharides can be potential binders for lithium-ion batteries due to their strong adhesion through numerous hydroxyl groups. As a novel waterborne lithiated polysaccharide derivative, cellulose sulfate lithium (CSL) is successfully synthesized and used as the binder for LiFePO₄ (LFP) cathode. The chemical structure of CSL is verified by FTIR-ATR, XRD, C¹³-NMR, GPC, EA, ICP and TGA. Compared to LFP cathode using polyvinylidene difluoride binder, electrochemical measurements show that the LFP cathode using CSL (LFP-CSL) has lower polarization and better rate performance owing to higher lithium-ion conductivity of CSL. The result of morphological analysis indicates that CSL binder can maintain an integrated LFP cathode structure during hundreds of cycles. As a result, the LFP-CSL cathode exhibits a discharge capacity of 133.4 mAh g^-1 and maintains remarkable cycle stability with retention of 93.1 % after 300 cycles at 1C. These findings provide novel insights into the rational design of the binders for the LFP cathode.

Preparation and characterization of sodium cellulose sulfate/chitosan composite films loaded with curcumin for monitoring pork freshness

Colorimetric films were prepared by incorporating curcumin into a sodium cellulose sulfate/chitosan composite. The morphology mechanical, and water vapor properties of the films were investigated, and their practical use in pork preservation was evaluated. The formula with the same charge ratio of sodium cellulose sulfate and chitosan had the highest tensile strength (TS). After the addition of curcumin, the tensile strength increased, whereas the water vapor permeability (WVP) decreased. The colorimetric film showed distinguishable color changes between the pH ranges of 3–10. The colorimetric film packaging extended the shelf life of the pork samples by 4 days. Moreover, the composite films were able to effectively monitor pork freshness. In conclusion, curcumin incorporated into sodium cellulose sulfate/chitosan composite films may have great potential in food packaging.

•

Sodium cellulose sulfate/chitosan/curcumin films were produced for food packaging.

•

The properties of composite films were enhanced due to electrostatic interaction.

•

The composite films changed their colors in response to the change of pH.

•

The composite films could monitor the freshness and extend shelf life of pork.