Lignin-based flame retardant via sequential purification-nanoparticle formation, and NP coupled chemical modification

• Published in: International journal of biological macromolecules 2024-11, Vol.281 (Pt 4), p.136499, Article 136499
• Main Authors: Won, Sungwook, Jung, Minjung, Bang, Junsik, Cho, Se Youn, Choi, In-Gyu, Kwak, Hyo Won
• Format: Article
• Language: English
• Subjects: Chemical treatment; Cotton Fiber; Flame retardant; Flame Retardants; Lignin - chemistry; Lignin nanoparticle; Nanoparticles - chemistry; Phytic Acid - chemistry; Polyethyleneimine - chemistry
• ISSN: 0141-8130; 1879-0003; 1879-0003
• DOI: 10.1016/j.ijbiomac.2024.136499

A nonhalogenated and ecofriendly flame-retarding material was developed using lignin, one of the main components of lignocellulosic biopolymers. Lignin was purified, dissolved, and formulated as nanoparticles and implemented after processing in an ecofriendly water-based γ-valerolactone (GVL) system at different concentrations. Nitrogen‑phosphorus sequential chemical modification was performed using polyethyleneimine (PEI) and phytic acid (PA), The char residue increased by ≥10 % compared with lignin nanoparticles (LNPs). A 10 wt% lignin-based flame retardant (L-FR) based on the weight of cotton fabric was introduced using a simple dipping method. Compared to existing cotton fabrics, the combustion time of L-FR treated cotton fabrics was reduced by 6.8 s. The maximum flame height was reduced by 5.4 cm, and the charcoal residue increased by 25 %. The flame-retarding mechanism of L-FR involved low-temperature dehydration, thermal decomposition of cellulose by the phosphorus component of PA and generation of expansive gas by the nitrogen component of PEI. These results showed that lignin-based raw material processing, polymer processing, and chemical modification were biomass-based, suggesting that lignin could be converted into an ecofriendly flame retardant, highlighting the feasibility of high-value-added lignin. [Display omitted] •Lignin nanoparticle (LNP) provides a large surface area to maximize flame retardant effectiveness.•Nitrogen‑phosphorus modification of lignin to develop lignin-based flame retardant.•The flame retardancy of cotton fabrics added with lignin-based flame retardant is improved.