(449e) Tailoring Lignin Chemistry to Manufacture Quality Material for Sustainable and Viable Biorefienry

The success of a modern biorefinery heavily depends on the availability of value-added product streams from lignin. Nevertheless, the quality and yield of lignin-derived materials heavily depends on the fundamental understanding of lignin chemistry. In particular, there is an imperative need to define the relationship between lignin chemical characteristics and performance of materials like carbon fiber, asphalt binder, and nanoparticles. In the past several years, our multidisciplinary team has significantly advanced the understanding of how to tailor lignin chemistry to improve the performance of lignin-based materials. For carbon fiber, we have revealed that carbon fiber mechanical and conductive performance heavily depends on the molecular weight, uniformity, chemical linkages, and functional group profile of lignin. The chemical characteristics determines the miscibility of lignin with guest polymer and thus impacts the crystallite content and size, resulting in carbon fibers with various performance. For nanoparticles, we have shown that the functional groups, chemical linkages, molecular weight, S/G ratio, and lignin condensation all could impact the hydrogen bond networks and electron double layers, which could in turn define the size, uniformity, and stability of lignin nanoparticles. For asphalt binder modifiers, the functional groups and molecular weight also impact the interaction with asphaltene, thus defining the high temperature and low temperature performance of asphalt binder. Overall, lignin chemistry is crucial for the performance of various high value products. The fundamental understanding transformed the biorefinery design, where new pretreatment, fractionation, and feedstock development strategies are being developed to tailor lignin chemistry toward best-performing lignin-based products.