| dc.description.abstract | The world economy is growing faster than ever, while environmental issues are getting
worse. The use of ecologically friendly materials has increased as a result of environmental
concerns. Promoting ecologically friendly products will be greatly aided by biomass, which is
a renewable resource. Lignin, as a main component of lignocellulosic biomass and one of the
most abundant biopolymers, is utilized extensively in a variety of industrial domains. It has
been proposed that lignin can be grafted with a variety of monomers, including glycidyl-
trimethylammonium chloride (GTMAC), acrylamide (AM), and acrylic acid (AA) to produce
water soluble products.
In this study, a detailed investigation was carried out on the free-radical polymerization
of kraft lignin, acrylamide (AM), and diallyl dimethylammonium chloride (DADMAC) to
generate flocculants for wastewater treatment. To comprehend the physicochemical properties
of this copolymerization system, in-situ nuclear magnetic resonance (NMR), rheological
analysis, and particle size techniques were conducted. The copolymerization of lignin-AM and
lignin-DADMAC had an activation energy of 65.7 and 69.3 kJ/mol, respectively, and followed
the first-order kinetic model, which was monitored by in-situ 1H NMR results. The highest
conversions of AM and DADMAC were 96% and 68%, respectively, in the copolymerization
of lignin, AM, and DADMAC at the molar ratio of 5.5: 2.4: 1, pH 2 and 85°C. It evidenced that
the participation of AM in the reaction was essential for polymerizing DADMAC to lignin due
to less steric hindrance of AM than DADMAC facilitating its bridging performance. Lignin
acted as an inhibitor in the copolymerization reaction, indicated by the monomer conversion
ratio and dynamic rheology of the reaction system. [...] | en_US |
