Chitosan composite films with high-content technical alkali lignin.

Area of Science:

• Materials Science
• Polymer Science
• Biomaterials

Background:

• Technical alkali lignin (TAL) is a promising material but limited by low incorporation (<10 wt%) in composites.
• Developing methods for high-content TAL composites is crucial for its large-scale production and application.

Purpose of the Study:

• To create high-strength chitosan-based composite films with significantly increased technical alkali lignin (TAL) content.
• To investigate the effect of water/N-methylpyrrolidone binary solvent mixtures on composite film properties.
• To explore the potential applications of these novel composite films.

Main Methods:

• Utilized water/N-methylpyrrolidone binary solvent mixtures to process chitosan and technical alkali lignin (TAL).
• Fabricated composite films with varying TAL content, including up to 23.4 wt% TAL.
• Characterized mechanical properties (tensile strength, elongation), surface morphology, hydrophobicity, thermal stability, UV-blocking, and anticorrosion efficiency.

Main Results:

• Composite films with 15 wt% TAL exhibited a 2.04-fold increase in tensile strength and 1.15-fold increase in elongation compared to pure chitosan (CS) film.
• A composite film with 23.4 wt% TAL (CS/TAL 6:4) showed a 25% enhancement in tensile strength over CS film.
• The films demonstrated surface protrusions, enhanced hydrophobicity, anti-swelling properties, good thermal stability, UV-blocking, and 99.98% anticorrosion efficiency for copper sheets.

Conclusions:

• A novel and effective method for preparing high-content TAL composite films using binary solvents was established.
• The developed chitosan-based composite films exhibit superior mechanical properties, hydrophobicity, and anticorrosion capabilities.
• This work provides a viable pathway for the large-scale application of TAL and can be extended to other polysaccharide/TAL composites.