Synthesis and Characterization of Lignin-Based Polycarbonate Polyols for Flexible Polyurethane Foam Application

Area of Science:

• Materials Science
• Polymer Chemistry
• Sustainable Chemistry

Background:

• Growing demand for sustainable materials necessitates alternatives to petroleum-based polyols.
• Lignin, a renewable biopolymer, presents potential for developing eco-friendly polyols.
• Flexible polyurethane (PU) foams are widely used but rely heavily on fossil fuels.

Purpose of the Study:

• To synthesize novel, high-performance lignin-based polycarbonate polyols.
• To evaluate their suitability for flexible PU foam applications.
• To investigate the structural modifications and resulting foam properties.

Main Methods:

• Synthesis of lignin-based polyols via transesterification with dimethyl carbonate.
• Characterization of polyol properties (hydroxyl value, viscosity).
• Structural analysis using nuclear magnetic resonance (NMR) spectroscopy.
• Formulation and testing of flexible PU foams with varying biobased polyol content.

Main Results:

• Synthesized lignin polyols with hydroxyl values of 111-179 mg KOH/g and viscosities of 12,000-26,000 mPa·s.
• Confirmed successful grafting of polyether chains and introduction of carbonate linkages via NMR.
• Formulated PU foams replacing up to 60% petroleum polyols showed superior mechanical strength and load-bearing capacity.
• Biobased foams exhibited enhanced thermal stability and shock absorption.

Conclusions:

• Novel lignin-based polycarbonate polyols are viable for high-performance flexible PU foams.
• These biobased polyols offer a sustainable alternative with improved material properties.
• The developed foams demonstrate enhanced performance and partial biodegradability.