Lignin is the only renewable biomass material which is composed of a large amount of aromatic components. Due to its unique structural and chemical properties, lignin is a valuable alternative material for producing high-value added phenolic polymers with lower cost. In this lab, a mild phenolic-liquefaction technology has been developed to depolymerize commercially avaliable high molecular weight sodium lignosulfonate (SL) solids to low molecular weight liquid phenolic polymer products (phenolated sodium lignosulfonate (PL)) with 100% yield. In order to optimze the process and understand the structural and funcational activity properties, the depolymerization products were treated with ultrafiltration and liquid–liquid extraction processes, and characterized with various methods including Advanced Polymer Chromatography (APC), FTIR, and SEM. APC results show that the elution time of the starting material (SL) is from 3 to 6 minutes, and the majority of PL components are eluted from 7 to 9 mimutes. The APC results indicate that the phenolic-liquefaction method has sucessully converted high molecular weight SL to lower molecular weight PL. FTIR analysis results confirm that the spectra of SL and liquid PL are very similar. both have aromatic skeleton vibration absorption at 1600, 1512 and 1426 cm<sup>-1</sup>. The FTIR and APC results reveal that the phenolic-liquefaction method does not dramatically change sodium lignosulfonate’s core aromatic structures except reducing its molecular weight. Interestingly, SEM results show that PL forms quite unified nano-powder dispersion. In this paper, the phenolic-liquefaction method and the product characterization are described. The lignin depolymerizaiton technique might open a new way to convert low cost biomass material to high value added phenol-rich products including natural amphiphile surfactants and high performance functional powder materials.

Characterization of phenolated sodium lignosulfonate prepared from lignin depolymerization at mild conditions

250th National Meeting (2015)

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