Journal ArticleThermal and Mechanical Properties of Lignin Derivative–Sulfur CompositesKapuge_Dona, Nawoda L [Department of Chemistry Clemson University Clemson South Carolina USA]; Sauceda‐Oloño, Perla Y [Department of Chemistry Clemson University Clemson South Carolina USA]; Smith, Rhett C [Department of Chemistry Clemson University Clemson South Carolina USA] (ORCID:0000000160878032)<title>ABSTRACT</title> <p>Lignin, comprising 20%–35% of lignocellulosic biomass, is the second most abundant biopolymer after cellulose. As the bioethanol industry expands, the accumulation of lignin by‐products necessitates innovative valorization strategies. This study explores the synthesis and characterization of lignin‐derived composites. Specifically, the reaction of 20 wt. % lignin‐derived guaiacol or syringol with 80 wt. % elemental sulfur gives composites GS₈₀and SS₈₀, respectively. The chemical structures of composites were elucidated using GC–MS,¹H NMR, and UV–Vis spectroscopy, revealing the formation of both SC_aryland SC_alkylbonds. Thermal and morphological analysis (via TGA, DSC, PXRD, and SEM‐EDS) indicated SS₈₀has higher crystallinity and thermal stability than GS₈₀, attributed to a higher degree of crosslinking and a greater content of dark sulfur. Mechanical testing showed SS₈₀exhibits superior compressional and flexural strengths, and enhanced Young's modulus and Shore hardness, compared to GS₈₀. Notably, the mechanical strength parameters for SS₈₀are comparable to those of C62 class bricks used in construction applications. These findings suggest that lignin‐derived composites, particularly those incorporating syringol, can provide viable alternatives to traditional materials in various applications, contributing to both waste valorization and sustainable materials science.</p>wiley2025-02-1510650095Journal of Polymer Science634789 to 7992642-4150https://doi.org/10.1002/pol.202405662203669National Science Foundation