Paper-Based Oil Barrier Packaging using Lignin-Containing Cellulose Nanofibrils.

Area of Science:

• Materials Science
• Sustainable Packaging
• Biomaterials

Background:

• Growing environmental and health concerns necessitate alternatives to conventional food packaging materials like fluorinated compounds and petroleum-based polymers.
• Cellulose nanofibrils (CNF) are known for their barrier properties, but the impact of lignin-containing cellulose nanofibrils (LCNF) on film characteristics remains underexplored.

Purpose of the Study:

• To investigate the effect of lignin in cellulose nanofibrils on the barrier and mechanical properties of coated paper for food packaging applications.
• To evaluate LCNF-coated paper's performance as a sustainable alternative to current packaging systems.

Main Methods:

• Thin films of LCNF and CNF were applied to paper substrates using a filtration technique simulating wet-end paper machine addition.
• Characterization included surface free energy, water contact angle, oxygen transmission rate (OTR), water vapor permeability (WVP), and grease resistance (kit test).
• LCNF-coated paper was formed into containers to assess long-term oil holding capacity and mechanical properties (tensile strength, elongation at break).

Main Results:

• Lignin distribution in LCNF enhanced surface water repellency.
• LCNF coatings exhibited OTR and WVP values comparable to CNF.
• LCNF significantly improved oil and grease resistance, achieving kit No. 12, and demonstrated no oil leakage for over five months in container form.
• Mechanical properties, including tensile strength and elongation at break, were improved in LCNF-coated papers.

Conclusions:

• Lignin-containing cellulose nanofibrils present a viable wood-based alternative for food packaging, offering enhanced oil barrier properties and improved mechanical performance.
• The study highlights LCNF's potential to replace environmentally concerning materials like fluorocarbons in packaging.