Some Kinetic Aspects of Wet-End Chemistry, 1995 Papermakers Conference Proceedings

L. Ödberg STFI Some kinetic aspects on polymeric retention aids and sizing chemicals used in the paper machine wet-end have been investigated. Under turbulent flow conditions the adsorption of polymers on fibers is very rapid occuring in less than 1s. The adsorbed polymers will reconform to a less expanded configuration. This reconformation process has a time constant of the order of IO s. The reconformation process influences the flocculation efficiency of the adsorbed polymer. The retention polymers can also transfer between fibers and fine material in the wet-end. In addition, the polymers can be cleaved at floc breakage. The exact extent to which these processes occur in practice in the paper machine wet-end is not clear. If the contact time is less than 20 s the effects of these processes might be limited. Sizing chemicals, such as alum and AKD, are also transferred. Experiments show that this transfer is probably of importance in a Practical papermaking situation.