Application of cationic polymer prepared from sulfuric acid lignin as a retention aid for usual rosin sizes to neutral papermaking

Abstract

Cationic polymers that acted as the retention aids for usual rosin sizes in neutral papermaking were prepared from sulfuric acid lignin (SAL), one type of acid lignin. To convert SAL to the cationic polymer (MP-SAL), SAL was phenolated and then treated by the Mannich reaction to introduce the amino groups. In the MP-SAL single system, MP-SAL exhibited high sizing effectiveness in neutral papermaking with the rosin emulsion size. However, MP-SAL showed no sizing effectiveness when soap rosin size was used. MP-SAL showed increased sizing effectiveness as the pK a of the introduced amino group increased. From this and comparison of the sizing degrees of MP-SAL and polyethylenimine, which possesses a linear structure, it was suggested that the sizing effectiveness was not only affected by the charge density and molecular weight, but also by the basicity of the introduced amino groups and the molecular structure of the retention aid. In the alum-MP-SAL dual system, alum and MP-SAL synergistically enhanced the sizing effectiveness in the rosin emulsion sizing at neutral pH. In turn, this allowed a decrease in the MP-SAL dosage and resulted in a small decrease in brightness.

Mapping of the cationic starch adsorbed on pulp fibers by ToF-SIMS

“…The handsheets were prepared according to our previous papers [1,3]. HBKP beaten to 432 mL and rosin size were used to obtain base papers possessing 2 and 36 s of Stö ckight sizing degree.…”

Preparation and characterization of crosslinked glyoxalated polyacrylamide paper‐strengthening agent

“…Paper‐strength properties can be improved by the addition of strengthening agents to the fiber suspensions at the wet end of papermaking. The charge density, molecular weight (MW), and molecular structure of an additive affect its strengthening ability 5. Crosslinked polymers, an innovative class of strengthening agents, are obtained by the interconnecting of molecular chains together 6.…”

Grafting strategies for hydroxy groups of lignin for producing materials

“…Generally, the amination reaction has been applied to lignin with the aim of generating cationic surfactants, slowrelease fertilizers, flocculants, heavy metal adsorbents, coagulants, cationic asphalt emulsifiers, curing agents of epoxy resin, anion-exchange resins and retention aids. 108,112,[196][197][198][199][200][201] Lignin amination could enhance the surface activity, water solubility, charge density and molecular weight of lignin. 69,202 Logically, introducing nitrogen-containing groups into lignin can render lignin an efficient adsorbent for heavy metals.…”