Blade-coated lignosulfonate sodium-modified PVA biodegradable barrier coatings

Overview

This research proposes a scalable method for producing 100% biodegradable barrier coatings using lignosulfonate sodium, a renewable and inexpensive byproduct of the biorefinery industry, combined with polyvinyl alcohol (PVA). The coatings are designed to deliver high moisture barrier capability along with a reinforcing structure, making them suitable for sustainable packaging applications. The goal is to enable processability and compatibility with commercially available coating techniques such as blade coating and roll-to-roll systems, addressing a key limitation of prior lignin-PVA research that relied on non-scalable methods like solution casting, spin-coating, or electro-spinning.

The resulting coatings leverage lignin's naturally excellent UV-shielding, moisture and oxygen barrier, anti-microbial, and reinforcing properties. Lignin and its derivatives are FDA-approved for direct and indirect food contact and are compatible with plastic recycling streams, making them attractive for sustainable packaging markets seeking alternatives to petroleum-based barrier materials.

Technical specifications

Key features:

• Renewable feedstock: Lignosulfonate sodium is a low-cost byproduct of the biorefinery industry, supporting circular economy goals
• Enhanced moisture barrier: Preliminary results show lignin reduces the water vapor transmission rate of pristine PVA from approximately 0.8 to around 0.3 WVT*100 (g/m²·day)·m
• Scalable processing: Designed for blade coating and roll-to-roll systems, enabling rapid film formation on absorptive substrates
• Multi-functional performance: Provides UV-shielding, oxygen barrier, anti-microbial, and reinforcing properties in a single coating
• Fully biodegradable: 100% biodegradable composition aligned with sustainable packaging requirements
• Regulatory compatibility: FDA-approved for direct and indirect food contact and compatible with plastic recycling

Research approach:

• Investigate rheological properties of lignin-PVA solutions to understand molecular interactions and entangled regimes for processability and performance
• Evaluate water and oxygen barrier properties of coated substrates
• Assess mechanical performance of blade-coated absorptive substrates

Technology readiness level

This project is at an early-to-mid stage of development (TRL 3-4). Proof-of-concept lignin-PVA blends have already been produced and demonstrated good barrier properties in laboratory settings. The proposed 6-month project will advance the technology toward pilot-scale validation by demonstrating compatibility with industrially relevant blade coating processes on absorptive substrates. The research team includes Dr. Ngoc Nguyen (Staff Research Scientist) and Dr. Daniel Krogstad (Senior Research Scientist) at the Illinois Applied Research Institute, University of Illinois Urbana-Champaign. The requested budget is $80,000 to complete proof-of-concept validation. Successful completion will establish the foundation for scaling toward commercial packaging applications.