Mechanically-robust biopolymer foam composites from plant byproducts

Overview

This technology produces mechanically robust foam composites from naturally abundant biopolymers, specifically cellulose and lignin derived from plant byproducts. Using designer acidic deep eutectic solvents (ADES), the process creates homogeneous cellulose-lignin solutions that form tunable foam structures with both covalent and noncovalent crosslinking for unprecedented resilience. The resulting biodegradable foams offer a sustainable alternative to petroleum-based materials such as EVA, with properties targeted toward athletic and protective applications. The one-pot procedure is compatible with compression molding and existing in-line formation processes, making it suitable for large-scale production.

Technical specifications

Key features:

• Uses acidic deep eutectic solvents (ADES) to dissolve and process cellulose and lignin without the irreversible bond breakages caused by strong acids, bases, or oxidizers
• ADES crystallizes at moderate temperatures, pushing cellulose fibers together into foam-like structures with tunable pore size, shape, and distribution
• Supports both covalent crosslinking (through esterification) and noncovalent crosslinking mechanisms for enhanced mechanical properties
• Achieves high cellulose loading greater than 5 wt% with chemical crosslinking verified through independent characterization
• Compatible with additives such as bivalent metal salts and small molecules with multiple carboxylic acids (e.g., citric acid) to promote toughness, water wicking, and other desirable properties
• One-pot formulation compatible with compression molding for scalable manufacturing
• Foam density, structure, and mechanical properties benchmarked against EVA standards

Validation methods include:

• Density measurement and imaging for pore size, shape, and distribution analysis
• Compression testing and Shore Hardness measurement
• Cyclic loading, impulse, and impact force testing for promising formulations

Technology readiness level

This technology is at an early-to-mid stage of development. The team has successfully formulated cellulose in molten salt hydrate ADESs, functionalized cellulose chains with renewable molecules for crosslinking, and synthesized crosslinked gels using techniques directly applicable to foam production. High cellulose loading and chemical crosslinking have been independently verified. Future validation will focus on co-formulating cellulose with lignin or tannic acid in ADES mixtures containing bivalent metal salts and citric acid, with target loadings of 2-5% w/w cellulose and greater than 0.5% w/w lignin. Cooling rate optimization, surfactant addition, and mechanical testing against EVA benchmarks will guide development toward commercial readiness.