Preparation method of sulfonated modified nanocellulose

The preparation method of sulfated modified Nanocellulose usually includes the following steps: sulfonation reaction and post-treatment steps. Sulfonation modification can impart more functionality to nanocellulose, such as increasing its hydrophilicity, introducing negative charge, etc. Here is a typical preparation process:

1. Material preparation:

The prepared nanocellulose is dispersed in an appropriate amount of solvent (such as water, DMF , etc.) and prepared into a uniform suspension.

Selection sulfonating agents: Commonly used sulfonating reagents include sulfuric acid ( of H ₂SO ₄ ), chlorosulfonic acid ( ClSO ₃ H ), etc.

2. Sulfation reaction:

At controlled temperature and time, the nanocellulose suspension is mixed with the sulfonation reagent and undergoes a sulfonation reaction. Common reaction conditions are as follows:

Sulfuric acid sulfonation: Perform for several hours at room temperature or slightly higher temperatures (such as 50-80℃ ).

Chlorosulfonic acid sulfonation: Reaction at a lower temperature (such as 0-5°C ) to avoid overreaction.

3. Post-processing steps

The nanocellulose after sulfonation reaction needs to be neutralized, cleaned and dried.

Neutralization: Neutralize the sulfonated nanocellulose suspension with an appropriate amount of alkali (such as sodium hydroxide) to remove residual acidic reagents.

Cleaning: Wash the nanocellulose repeatedly with a large amount of distilled water to remove neutralized salts and unreacted reagents.

Dry: The washed nanocellulose is dried by freeze-drying or spray-drying to obtain a sulfonated modified nanocellulose powder.

4. Characterization and application

The sulfonated modified nanocellulose was characterized by Fourier transform infrared spectroscopy ( FTIR ), nuclear magnetic resonance ( NMR ), X- ray photoelectron spectroscopy ( XPS ), etc., and its structural and functional groups were determined.

The preparation process of sulfonated modified nanocellulose includes the preparation of nanocellulose, sulfonation reaction and post-treatment steps. By selecting suitable sulfonation reagents and reaction conditions, sulfonic acid groups can be effectively introduced to impart new functional properties to the nanocellulose.