Open AccessProduction and Application of Triblock Hydrolysis Lignin-Based Anionic Copolymers in Aqueous Systems
Author(s) -
Sanaz Sabaghi,
Niloofar Alipoormazandarani,
Pedram Fatehi
Publication year - 2021
Publication title -
acs omega
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.779
H-Index - 40
ISSN - 2470-1343
DOI - 10.1021/acsomega.0c06344
Subject(s) - lignin , adsorption , copolymer , polymer , chemical engineering , hydrolysis , polymerization , polymer chemistry , monomer , aqueous solution , biopolymer , materials science , chemistry , organic chemistry , engineering
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 ( 1 H 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 Al 2 O 3 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 Å 2 ) at the interface of water and Al 2 O 3 . 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 Al 2 O 3 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.