Amphiphilic Copolymers Derived from Butanosolv Lignin and Acrylamide: Synthesis, Properties in Water Solution, and Potential Applications

Abstract

In this work, a series of amphiphilic lignin-acrylamide copolymers was synthetized via a "grafting from" approach using α-butoxylated organosolv lignin. This lignin is obtained in high yield via a mild organosolv extraction with butanol and contains a well-defined modified β-O-4 structure that allows for site-selective modification of the primary alcohol in the γ-position. The modified lignin was then used as a precursor of amphiphilic copolymers by reaction with acrylamide, either via free radical polymerization or via atom transfer radical polymerization after converting the lignin into a suitable macroinitiator. The effect of the synthetic method and acrylamide/lignin ratio on the final properties was studied and compared. Relevant solution properties, in particular, shear viscosity and interfacial and surface tension, showed that different synthetic methods and polymer compositions allow a tuning of the solution behavior toward specific potential applications, such as emulsion stabilization or enhanced oil recovery. Furthermore, it was preliminarily shown that the obtained polymers may potentially display low cytotoxicity, further increasing the possibilities for applications.

Extraction and Surfactant Properties of Glyoxylic Acid‐Functionalized Lignin

“…As previously shown, GA‐lignin (Figure 3a and Figure 6, red bars, and Table S5) was able to lower the surface tension of the water/air from 72.8 (Figure 6, green bar) to 31 mN m −1 regardless of the pH of the aqueous phase. Specifically, GA‐lignin at pH 7 and 14 lowered the surface tension as well as or more than all the other lignins, such as the industrial Kraft lignin and lignosulfonates, or literature‐reported lignins that underwent further chemical modification to impart them with surfactant properties including sulfomethylated lignin, [39] dodecyl succinic acid‐, [35] polyethylene glycol (PEG)‐, [23] or polyacrylamide (PAM)‐ [40] grafted lignins (Figure 6, blue bars).…”

“…[35]; PAM-grafted butanosolv lignin: Ref. [40]; PEG-grafted enzymatic lignin: Ref. [23]; sulfomethylated alkali lignin: Ref.…”

“…ChemSusChem literature-reported lignins that underwent further chemical modification to impart them with surfactant properties including sulfomethylated lignin, [39] dodecyl succinic acid-, [35] polyethylene glycol (PEG)-, [23] or polyacrylamide (PAM)- [40] grafted lignins (Figure 6, blue bars).…”

RDRP (Meth)acrylic Homo and Block Polymers from Lignocellulosic Sugar Derivatives

“…In the same line, RDRP methods have been recently applied also to the synthesis of well-defined (meth)acrylic polymers from lignin fractions of lignocellulosic materials. [142][143][144] Future opportunities we envision in this area include the synthesis of more complex polymeric architectures, scale up of both monomer syntheses and polymerizations, as well as bio-based poly(meth)acrylate designed for currently unexplored applications. Block copolymers give interesting opportunities due to their ability to phase separate and form selfassembled nanostructures, which could be exploited further.…”

Recent Studies on the Preparation and Application of Ionic Amphiphilic Lignin: A Comprehensive Review

“…Sulfonate lignin is the most important anionic structure in lignin, and its main sources include sulfite pulping waste liquor and sulfonated alkali lignin. Chemically modified amphiphilic lignin polymers are typically used as fine chemicals and are used for practical applications such as suspension, solubilization, wetting, and as detergent agents. − Most existing amphiphilic materials such as surfactants are toxic, nonbiodegradable, and pollute the environment. In the future, surfactant products will gradually develop in the direction of green raw materials, environmentally friendly products, and safe treatment.…”