Polarity of Cationic Lignin Polymers: Physicochemical Behavior in Aqueous Solutions and Suspensions

Abstract

The structure of cationic monomers can significantly impact the polarity of lignin after polymerization. Cationic hydrolysis lignin (CHL) polymers were produced by polymerizing hydrolysis lignin (HL) with [3‐(methacryloylamino)propyl] trimethylammonium chloride (MAPTAC) or [2‐(methacryloyloxy)ethyl] trimethyl ammonium chloride (METAC). The METAC monomer has an oxygen atom, with larger electronegativity, in its molecular structure, whereas the MAPTAC monomer contains a nitrogen atom, as well as an extra nonpolar CH2 group, facilitating investigation into the effects of the polarity of CHLs on their physicochemical performance in an aqueous system. CHL polymers are analyzed and their interactions with clay particles are determined in colloidal systems. CHLs are designed to have similar charge densities (2.1–2.2 mmol g−1) and molecular weights (55000–60000 g mol−1 ). The hydrodynamic radius (Hy) and radius of gyration, (Rg) of HL‐METAC are larger than those of HL‐MAPTAC, implying a more 3‐dimensional structure of HL‐METAC in aqueous solution. The stability ratio of kaolin particles affirms the better performance of HL‐METAC in comparison to HL‐MAPTAC, which reflects the better flocculation efficiency of HL‐METAC. The results also reveal that salt and urea aqueous solutions affect the Hy, Rg, and configuration of CHL polymers, which alters the flocculation efficiency of HL‐METAC and HL‐MAPTAC polymers in kaolin suspensions.

Preparation of a Lignin-Based Cationic Flocculant and Its Application in Kaolin Suspension Treatment

“…Moreover, AL-g-PAMA #5 contained more particles than CPAM. These results confirmed that flocculation efficiency improved after treatment with AL-g-PAMA #5 [50].…”

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

“…The flocculation performance of HAMs was compared with those of other bio-based flocculants, and the results are tabulated in Table 4. Compared to our previous work, 6 the molecular weight of HL increased significantly after polymerizing with two monomers (i.e., AM and AA) and thus yielded higher particle removals by generating a larger chord length. Although cationic HL-graf t-[2-(methacryloyloxy)ethyl]trimethyl ammonium chloride (HL-METAC) was used at a lower dosage, it was not as efficient as HAMs in particle removal from model wastewater.…”

“…Lignin, a highly branched aromatic polymer, is now considered the main aromatic renewable resource with attractive properties, such as biodegradability, as well as antimicrobial and UV activities. , Enzymatically hydrolysis lignin (HL) is derived from the biofuel production process and has been recognized to have poor hydrophilicity and low reactivity, which impede its conversion to value-added products. − Therefore, the advancement in the applications of hydrolysis lignin (HL) necessitates the modification of its chemical structure. Numerous studies demonstrated that the polymerization of lignin with functional monomers is a promising approach for lignin valorization, which can enhance both the molecular weight and charge density of the lignin macromolecule. − Previously, the polymerization reaction of kraft lignin (KL) with acrylamide (AM) and acrylic acid (AA) , was studied for producing a lignin-based material with multifunctional applications. However, the production of HL with both AM and AA monomers in a ternary reaction system has not been investigated, which is covered in the present study.…”

Lignin use in nonwovens: A review

“…In the past, to design polymers with different polarities and solubilities, polymerization reactions were performed. Polarity had the potential to influence the polymer's hydrogen bonding and electrostatic interaction with other colloidal particles (Sabaghi and Fatehi 2020). However, as lignin contains both hydrophobic and hydrophilic groups, it has intrinsic multi-polarity (ILI).…”

“…However, as lignin contains both hydrophobic and hydrophilic groups, it has intrinsic multi-polarity (ILI). Studies suggest that the polarities of polymers may directly affect their performance in interacting with other particles in suspensions (Sabaghi and Fatehi 2020).…”