ENHANCEMENT OF THE RETENTION PERFORMANCE OF THE POLY(ETHYLENE OXIDE) TANNIC-ACID SYSTEM BY POLY(DIALYLDIMETHYL AMMONIUM-CHLORIDE)

The retention performance of the poly(ethylene oxide) (PEO) and tannic acid (TA) dual system was studied in the presence of poly(diallyldime thyl ammonium chloride) (PDADMAC). The zeta potential, and size of the association complex between PEO and TA in the presence of PDADMAC as well as the infrared spectra of TA and the PEO-TA system were also stu died. It was shown that hydrogen bonds are formed between the phenolic and acidic groups of TA and the oxygen atoms of the PEO macromolecule s. Moreover, it was found that the presence of small quantities of PDA DMAC enhances the fibre fines and clay first pass retention. The maxim um effect was observed with an amount of added PDADMAC equal to 20% of the amount of added PEG. Further addition of PDADMAC was found to dec rease the retention probably because it recharges the surface to posit ive. When clay was replaced by ground calcium carbonate no retention i mprovement was detected. This is most likely due to the presence of ca lcium ions.