Crosslinked starch-coated cellulosic papers as alternative food-packaging materials

Area of Science:

• Materials Science
• Chemical Engineering
• Biotechnology

Background:

• Conventional papermaking removes lignin and amorphous components from cellulosic fibers.
• This removal is typically achieved through pulping and multi-level bleaching processes.
• Residual lignin is often discarded, representing a potential loss of valuable material properties.

Purpose of the Study:

• To investigate the beneficial effects of residual lignin on the surface of alkali-treated cellulosic fibers.
• To develop an alternative food-packaging cellulosic paper utilizing these lignin-containing fibers.
• To evaluate the impact of residual lignin on the mechanical, surface, and flame resistance properties of the paper.

Main Methods:

• Cellulosic papers were prepared from Alfa plant fibers using alkali treatment and compression molding.
• Fibers were bleached, and residual lignin was retained on the surface of alkali-treated fibers.
• Papers were coated with crosslinked starch via solvent-casting to enhance properties.

Main Results:

• Residual lignin significantly improved interfacial adhesion, leading to denser and more compact paper structures.
• Enhanced lignin content resulted in superior water resistance compared to purely bleached fibers.
• Improved flame resistance was observed due to lignin's promotion of char formation.
• Mechanical testing revealed increased rigidity and maintained flexibility (folding endurance) with lignin presence.

Conclusions:

• Residual lignin in alkali-treated cellulosic fibers positively impacts paper properties for food packaging.
• The developed cellulosic papers exhibit enhanced water resistance, flame retardancy, and mechanical strength.
• These lignin-containing cellulosic papers offer a promising, high-quality alternative for food-packaging applications.