Blended amphoteric PAMs: High performance as retention aids

A recent rise in pulp fineness and inorganic salt ratios has reduced the efficiency of currently used retention aids. Moreover, high-speed paper production processes require high performance retention aids that do not degrade paper formation. In this study, we synthesized anionic- and cationic-unit rich amphoteric polyacrylamides (PAMs) and evaluated a blend of the two as a retention aid. Analyses of stress changes in the floc generation process and the water solution characteristics of each PAM and blend suggest that this blend system has effectively assisted proper floc generation and resulted in enhanced performance. We also propose a possible flocculation mechanism that supports the analyses and discuss the mechanistic aspects of the present system.