A Dual Valorization Strategy of Barley Straw for the Development of High-Performance Bio-Based Polyurethane Foams

Area of Science:

• Materials Science
• Biomass Valorization
• Polymer Chemistry

Background:

• Lignocellulosic biomass, like barley straw, presents a sustainable resource for material development.
• Valorization strategies are needed to efficiently utilize all biomass components, minimizing waste.
• Bio-based polymers, such as polyurethane foams, offer eco-friendly alternatives to petroleum-based materials.

Purpose of the Study:

• To develop a zero-waste valorization strategy for barley straw.
• To synthesize bio-polyols and lignin-containing cellulose nanofibers (LCNF) from barley straw.
• To create and characterize bio-based polyurethane foams using these derived materials.

Main Methods:

• Barley straw was fractionated to isolate lignin for lignin bio-polyol (LBP) synthesis.
• Unfractionated barley straw was used to create straw bio-polyol (SBP).
• LCNF was produced from the same feedstock and incorporated into polyurethane foams at varying concentrations.

Main Results:

• Bio-polyols derived from lignin (LBP) yielded foams with lower density and homogeneous structure.
• Bio-polyols from unfractionated straw (SBP) resulted in stiffer, more crosslinked foams.
• LCNF incorporation enhanced mechanical properties, with optimal reinforcement at 3 wt.% (SBP) and 5 wt.% (LBP), increasing compressive strength by up to 121%.

Conclusions:

• A dual-route strategy enables comprehensive valorization of barley straw into bio-polyols and LCNF.
• This approach facilitates a systematic understanding of biomass component roles in polyurethane foam synthesis.
• The developed materials offer a sustainable, low-impact route to high-performance bio-based polyurethane foams.