Lignin‐g‐poly(acrylamide)‐g‐poly(diallyldimethyl‐ ammonium chloride): Synthesis, Characterization and Applications

Abstract

The search for a renewable substitute to petroleum‐based products has fueled increasing research on lignin, an under‐utilized product from pulping processes. In this work, lignin was copolymerized with acrylamide (AM) and diallyldimethylammonium chloride (DADMAC) under acidic conditions with Na2S2O8 as an initiator, generating a cationic water‐soluble lignin‐g‐P(AM)‐g‐P(DADMAC) copolymer. The optimal reaction conditions, using a 5×4 factorial design experiment, were determined to be an AM/DADMAC/lignin molar ratio of 5.5:2.4:1, 90 °C, 0.26 mol L−1 of lignin, and pH 2. Under the optimal reaction conditions, the resulting lignin‐g‐P(AM)‐g‐P(DADMAC) copolymer was 83 % soluble in an aqueous solution (at 10 g L−1) and at neutral pH. The copolymer had a charge density of 1.27 meq g−1, molecular weight of (1.33±0.08) ×106, an AM grafting ratio of 112 wt %, and a DADMAC grafting ratio of 20 wt %. In addition, the activation energy for producing this copolymer as well as the thermal and rheological properties of the copolymer were determined. The flocculation performance of lignin‐g‐P(AM)‐g‐P(DADMAC) copolymer was evaluated in a kaolin suspension, which showed that the lignin copolymer had a comparable flocculation efficiency with the synthetic analogue of P(AM)‐g‐P(DADMAC) at pH 6.

Selfing mutants link Ku proteins to mating type determination in Tetrahymena

“…The macronucleus is polyploid at the time of DNA rearrangements and potentially can generate multiple mating-type gene pairs within a single nucleus if rearrangement occurs independently in each chromatid. The proportions of these gene pairs in a nucleus could be skewed if the process was not entirely random, as suggested before, possibly through a hypothetical “intranuclear coordination” [ 18 , 24 , 25 ]. When growth resumed after conjugation, these copies presumably can assort to different sister nuclei due partly to the lack of centromeric function of the macronuclear chromosomes, eventually producing cells with only 1 form of mating-type gene pair in the macronucleus.…”

“…In selfing cells, we have uncovered 2 types of DNA abnormality: dual normal MTA / MTB gene pairs and/or mis-paired MTA / MTB genes. It has been shown that roughly half of the newly developed macronuclei are heterogeneous, with multiple potentials for mating types [ 24 , 25 ]. The heterogeneity usually consisted of 2 mating types (occasionally 3) as the newly developed macronucleus starts to divide, and the mating type combinations were not entirely random.…”

Lignin for polymer and nanoparticle production: Current status and challenges

“…In another study, chitosan‐lignin‐acrylamide graft polymer was used as a flocculant exhibiting 99.3% and 67.0% for reactive orange C‐3R and methyl orange dye removals, respectively . Recently, various cationic and anionic lignin polymers with different molecular weights (MW) and charge densities have been introduced as flocculants for altered systems . The polymerization of kraft lignin and METAC induced a lignin polymer with a charge density of 2.93 mmol/g and a molecular weight of 1650 kg/mol as an effective flocculant for dyes .…”

“…[73] Recently, various cationic and anionic lignin polymers with different molecular weights (MW) and charge densities have been introduced as flocculants for altered systems. [68,69,71,72,75,81,82,108] The polymerization of kraft lignin and METAC induced a lignin polymer with a charge density of 2.93 mmol/g and a molecular weight of 1650 kg/mol as an effective flocculant for dyes. [70] The polymerization of acrylic acid, AA, and kraft lignin was also successfully carried out.…”

Modification of Kraft Lignin with Dodecyl Glycidyl Ether

“…Lignin is one of the main components of biomass . Lignin has primarily been used as a fuel source, but recent studies have shown that it could be converted into several value‐added products .…”