Production and Application of Triblock Hydrolysis Lignin-Based Anionic Copolymers in Aqueous Systems

Abstract

Although lignin is currently an under-utilized biopolymer, it has the potential to be valorized through different modification pathways to yield alternative products to petroleum-based ones. In this work, hydrolysis lignin (HL) was copolymerized with acrylamide (AM) and acrylic acid (AA) under acidic conditions to generate the lignin/AM polymer (HM), lignin/AA polymer (HA), and lignin/AM/AA copolymer (HAM) with different negative charge densities and molecular weights. Lignin-based polymers characterized by advanced tools, such as proton nuclear magnetic resonance (1H NMR), gel permission chromatography (GPC), and elemental analysis confirmed the successful polymerization of HL with AM, AA, or AM/AA monomers. The adsorption analysis using a quartz crystal microbalance (QCM) revealed that compared to diblock HM and HA, the triblock copolymers of HAM adsorbed more on the Al2O3 surface and generated a bulkier adsorbed layer, which is important for lignin-based coating formulation. HAM1 with a lower charge density yielded a higher surface excess density, while HAM2 with a larger R h occupied more space (153.7 Å2) at the interface of water and Al2O3. In suspension systems, because of the higher M w, R h, and adsorption affinity, the bridging performance of HAM2 was more remarkable than that of the other lignin derivatives for Al2O3 particles via forming stronger flocs (with a deflocculation parameter, T df, of 80.6 s). However, the diblock lignin–AA (HA1) polymer showed the fastest floc regrowth capability after reducing the shear forces (with a reflocculation parameter, T rf, of 62.5 s). The high thermal stability, T g, and rheological characteristics of the HAM copolymer proved that it can be an excellent material for coating formulations and flocculants for wastewater treatment systems.

A Green Cement Plasticizer from Softwood Kraft Lignin

“…The chemical structure of the samples was analyzed by XPS using a Kratos AXIS Supra, Japan, with the monochromatic AL anode. A previously described method was followed to analyze the lignin samples . The dried samples were analyzed by a 375 W X-ray.…”

“…A previously described method was followed to analyze the lignin samples. 25 The dried samples were analyzed by a 375 W X-ray. In this experiment, the number of steps, sweep, and dwell time were 230 s, 60 s, and 260 ms, respectively.…”

Generation of Sulfonated Lignin-Starch Polymer and Its Use As a Flocculant

“…A lower concentration of phenolic hydroxyl groups in the copolymers is associated with a higher grafting ratio of MPSA to TOL, as more active phenolic sites are occupied after the reaction. 39 The MW and R g of TOL, starch, and anionic TOL-starch copolymers are also summarized in Table 3. As expected, starch showed a significantly larger MW and R g than TOL did.…”

Functional Lignin Building Blocks: Reactive Vinyl Esters with Acrylic Acid

“…27 These can result in lignin having new functionalities, allowing its use, for example, in coatings and flocculants. 28 Various types of consumer products are produced through radical polymerization, such as foams made by emulsion polymerization of polystyrene, 29 plastic tubings made by poly(vinyl chloride), 30 and latex paint made by copolymerizing methyl methacrylate and n-butyl acrylate. 31 Previous research explored the applicability of telechelic lignin by grafting vinyl groups on lignin through chemical modification methods.…”

“…Further, the introduction of vinyl groups provides wide opportunities in polymer synthesis, especially radical polymerization . These can result in lignin having new functionalities, allowing its use, for example, in coatings and flocculants . Various types of consumer products are produced through radical polymerization, such as foams made by emulsion polymerization of polystyrene, plastic tubings made by poly­(vinyl chloride), and latex paint made by copolymerizing methyl methacrylate and n -butyl acrylate .…”