Emulsion Stabilization with Lignosulfonates

Abstract

Lignosulfonates are biobased surfactants and specialty chemicals. Due to their amphiphilic nature, they can be utilized in many technical applications, such as plasticizers, dispersants, stabilizers, and agrochemical formulations. Here, their ability to stabilize emulsions plays an important role. This chapter hence explains the fundamentals of emulsion stabilization with lignosulfonates. First, basic concepts are introduced along with the production and chemical make-up of lignosulfonates. Second, the interfacial activity is discussed. Parameters that affect interfacial activity and emulsion stabilization efficiency of lignosulfonates are furthermore treated. Such parameters may include salinity, pH, the presence of cosolvents and cosurfactants. Third, the underlying mechanisms of emulsion stabilization are outlined. The goal of this chapter is to introduce the reader to important fundamentals, and to draw the link between basic research and industrial practice.

Functional surfaces, films, and coatings with lignin – a critical review

“…It comes to no surprise that the dominant use of technical lignin is in water-soluble surfactants, as polydispersity is a key feature here. 3 As has been pointed out, the performance of surfactant-blends often outperforms single surfactants in real-world applications, since the mixture can preserve its function over a wider range of environmental conditions. A second example of key properties would be lignin's polyphenolic structure, which is not found in common polysaccharides.…”

“…Technical lignin is the product of biomass separation processes and hence differs from natural or pristine lignin, as it is found in lignocellulose biomass. 3 The composition and properties of technical lignin are largely determined by their botanical origin, extraction process, purification, and potential chemical modification. 4 Presently, there are some 50–70 million tons technical lignin available from pulping or biorefinery operations.…”

Interfacial Adsorption of Oil-Soluble Kraft Lignin and Stabilization of Water-in-Oil Emulsions

“…Hydrophobic interactions and π–π stacking were pointed out as the main mechanisms governing such aggregation. , Water-soluble lignin can furthermore form viscoelastic interface layers, which can exhibit gelling properties in the presence of multivalent cations . Stabilization of oil-in-water emulsions is achieved by a number of mechanisms, including steric hindrance, the Marangoni–Gibbs effect, electrostatic repulsion, viscoelastic interface layers, and particle stabilization . While a combination of effects usually occurs, the dominant stabilization mechanism depends on the composition and aggregate state of the lignin.…”

“… 22 Stabilization of oil-in-water emulsions is achieved by a number of mechanisms, including steric hindrance, the Marangoni–Gibbs effect, electrostatic repulsion, viscoelastic interface layers, and particle stabilization. 23 While a combination of effects usually occurs, the dominant stabilization mechanism depends on the composition and aggregate state of the lignin. For instance, water-soluble lignin can act by interfacial adsorption and electrostatic repulsion at sufficiently large charge density, 24 whereas water-insoluble lignin may form particle stabilized Pickering emulsions.…”