Ionic Liquid Lignosulfonate: Dispersant and Binder for Preparation of Biocomposite Materials

Ryan Guterman,Elinor Josef,Valerio Molinari

doi:10.1002/ange.201907385

Ryan Guterman, Elinor Josef + Show 1 more

Open Access

https://doi.org/10.1002/ange.201907385

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Abstract

AbstractIonic liquid lignins are prepared from sodium lignosulfonate by a cation exchange reaction and display glass transition temperatures as low as −13 °C. Diethyleneglycol‐functionalized protic cations inhibit lignin aggregation to produce a free‐flowing “ionic liquid lignin”, despite it being a high‐molecular‐weight polyelectrolyte. Through this approach, the properties of both lignin and ionic liquids are combined to create a dispersant and binder for cellulose+gluten mixtures to produce small microphases. Biocomposite testing pieces are produced by hot‐pressing this mixture, yielding a material with fewer defects and improved toughness in comparison to other lignins. The use of unmodified lignosulfonate, acetylated lignosulfonate, or free ionic liquid for similar materials production yields poorer substances because of their inability to maximize interfacial contact and complexation with cellulose and proteins.

Highlights

Ionic liquid lignins are prepared from sodium lignosulfonate via a cation exchange reaction and display glass transition temperatures as low as -13 °C
Lignin extracted from plant matter possesses ill-defined molecular structures whose properties, molecular weight, and chemical functionality are highly dependent on its isolation method and source,[4] complicating their use
Their biodegradability makes them suited towards these applications while the presence of both modified and unmodified hydroxyl groups assist in dispersing a wide variety of substances, including dyes,[9] coal slurries,[10]

Summary

Introduction

Ionic liquid lignins are prepared from sodium lignosulfonate via a cation exchange reaction and display glass transition temperatures as low as -13 °C. The modification of SLS with organic cations by cation exchange produces “ionic liquidlignin”, which acts as a dispersant and binder for plant-based biopolymers and assists in the fabrication of lignin-cellulose composites. We found that lignin modified with the tris-[2(2-methoxyethoxy)ethyl]amine (TrisEG; Fig 1, bottom) possessing ethyleneglycol functionality effectively dispersed cellulose+gluten microphases (1-10 μm) while acting as a binder to improve mechanical properties.

Results

Conclusion