Lignin micro/nanoparticles: synthesis, properties, and application to endow polyvinyl alcohol film with multi-functionality

• Published in: Chemical engineering journal (Lausanne, Switzerland : 1996) Switzerland : 1996), 2023-10, Vol.473, p.145233, Article 145233
• Main Authors: Xu, Ying-Hong, Li, Ming-Fei, Peng, Feng
• Format: Article
• Language: English
• Subjects: Controllable preparation; Fractionation; Lignin micro/nanoparticles; Polyvinyl alcohol; γ-Valerolactone
• ISSN: 1385-8947; 1873-3212
• DOI: 10.1016/j.cej.2023.145233

[Display omitted] •Lignin spheres were synthesized through dropping/dialysis nanoprecipitation.•The synergistic effect of parameters on the synthesis LMNPs was assessed.•The monodispersed LMNPs were produced from lignin fraction with low PDI.•The multifunctionality of PVA film was endowed by LMNPs with different structures.•The PVA/LMNPs film exhibited excellent mechanical property and UV shielding ability. Lignin, as an abundant natural polymer, has great potential in the synthesis of multifunctional micro/nanoparticles. However, the synthesis methods and parameters during the preparation process impact the controllability of lignin micro/nanoparticles (LMNPs), thereby affecting the performance of composite materials containing LMNPs. In this study, a green, simple, and applicable method for organosolv lignin was proposed for the synthesis of LMNPs using recyclable γ-valerolactone and the parameters (lignin concentration, stirring speed, dropping speed, water/solvent ratio, and lignin structure) were systematically investigated. The tuning of multiple properties of the composites was investigated by mixing LMNPs with polyvinyl alcohol (PVA). Results indicated that synthesis parameters affected the LMNPs formation, leading to aggregation/fusion of LMNPs. The obtained spherical LMNPs were electrostatically stable in pH 4–12, uniform (0.09 PDI), and excellent in thermal stability and antioxidant activity. Based on diffusion-restricted cluster–cluster aggregation, LMNPs around 157–442 nm were fabricated through π-π interactions. The PVA/LMNPs composite films showed excellent properties in terms of mechanical properties, thermal stability, UV shielding capacity, and hydrophobicity. The LMNPs with different structures improved the properties of polyvinyl alcohol films, providing a controllable approach for the development of biodegradable food/medical packaging materials and UV-shielding biomaterials.