Lignin nanoparticles by ultrasonication and their incorporation in waterborne polymer nanocomposites

Abstract

Lignin nanoparticles (nanolignin, NL) were prepared in this work by ultrasonic treatment of softwood kraft lignin to obtain lignin‐water dispersions with excellent colloidal stability. A thorough characterization of the chemical, physical, and morphological properties of the new NL particles allowed for direct comparisons with the untreated parent material. Such NL particles were incorporated into a waterborne thermoplastic polyurethane matrix at different concentrations to yield bio‐based nanocomposite materials. The effect of the bio‐filler type (NL vs. untreated lignin) and loading on the chemical, physical, thermal, and morphological characteristics of the resulting nanocomposites was extensively investigated. In addition, tensile tests carried out on these systems highlighted the superior mechanical properties of NL‐based nanocomposites compared to composite materials incorporating untreated lignin. The results of this study provide a direct demonstration of an easy and environmentally friendly approach to obtain waterborne polyurethane‐based nanocomposites reinforced with NL in a relatively straightforward and accessible way and clearly evidence the potential of lignin nanoparticles as fully bioderived fillers for advanced nanocomposite applications. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 45318.

Green synthesis of lignin nano- and micro-particles: Physicochemical characterization, bioactive properties and cytotoxicity assessment

“…T g is directly related to the mobility of the macromolecular chains, which may be affected by a complex interplay between several factors including the molecular weight of the material, the presence of chemical or physical crosslinks, and the presence of strong intermolecular interactions between the macromolecular chains such as intermolecular hydrogen bonds [15]. Gupta et al [60] reported similar results for LPs produced from low sulfonated lignin (lignin protobind-1000) using acid precipitation method, where the T g value of LNPs (153.7°C) was higher than the T g of lignin (151.5°C).…”

“…Nowadays, the development of NPs from lignin has gained interest, given its nature, for drug delivery systems [9][10][11], delivery of hydrophobic molecules [12], improvement of UV barrier [13,14], as reinforcing agent in nanocomposites [15], sorbents for heavy metal ions and other environmental pollutants, and antibacterial and antioxidant applications [16][17][18][19]. They have also been used as an alternative to inorganic NPs due to some safety issues raised in recent years [8].…”

Tuning Lignin Characteristics by Fractionation: A Versatile Approach Based on Solvent Extraction and Membrane-Assisted Ultrafiltration

“…To date, only a small part of the technical lignins produced worldwide is actually used for material manufacturing and chemical synthesis, as the majority is being burnt for energy recovery at the processing plant itself [8]. The main existing pathways for lignin valorization aim at its direct utilization (e.g., as micro or nanostructured filler in blend with polymers [9,10] or as a water-reducing agent for concrete [11]) with limited processing after the initial cellulose separation from the original biomasses. Lignin represents, however, a highly abundant natural aromatic feedstock with potentially very interesting applications in a sustainable economy scenario, especially considering the high primary production volumes and the inherently renewable nature of this resource [12].…”

Two-Step Fractionation of a Model Technical Lignin by Combined Organic Solvent Extraction and Membrane Ultrafiltration

“…9,10 The main pathways for lignin valorization typically aim for the production of materials including its use as a filler, in blend with polymers, as a copolymer, and as a water-reducing agent for concrete, allowing its direct exploitation without requiring a preliminary depolymerization step after the original biomass fractionation. 11−16…”