The effect of various retention aids on retention and formation

Abstract The interdependency between retention and paper formation was studied using a previously designed R-F (Retention and formation)-machine. The objective of the work was to investigate the retentionformation relationship for different types of retention aid systems. Both single-component cationic polyacrylamides with varying molecular weights and polyacrylamide- based microparticulate retention aids were investigated on the R-F-machine, for a fine paper stock with addition of 25% filler (based on total solids content). Results showed that the retention-formation relationship was not dependent on the retention aid systems used, since all systems provided similar relationships. In terms of the retention performance, significant differences were observed, depending on the choice of microparticle system and molecular weight of the used cationic polyacrylamide.