Recent trends such as increased production and decreased fresh water usage requires the development of more efficient retention and drainage aids. We synthesized cationic polyvinylphenol (vinyl benzyl trimethylammonium chloride-vinylphenol copolymer) as a newly developed cofactor for a polyethyleneoxide based retention system.
Maximum fine retention and drainage was obtained by using cationic cofactor with 30 mol% of cationic group and 70 mol% of phenolic hydroxide group. It was postulated that the charge and charge density of vinyl phenol based cofactor was the most important property. Instead of cationic cofactor, we used pDADMAC and PFR and compared this system to a conventional PFR (phenol formaldehyde resin)/PEO system. Maximum fine retention and drainage was obtained by using pDADMAC and PFR with 45 mol% of cationic group and 55 mol% of phenolic hydroxide group. It was postulated that pDADMAC was adsorbed onto both pulp fiber and PFR, therefore the optimum ratio of cationic group was higher than the case of cationic cofactor.
PFR adsorption amount was measured when pDADMAC was added to the pulp slurry containing 20% PCC filler. pDADMAC addition increased the adsorption amount of PFR onto the pulp slurry. When comparing the PFR/PEO and the pDADMAC/PFR/PEO systems, the collision frequencies among pDADMAC, PFR. PEO molecules and PCC particles suggest that the bridging component of the overall retention mechanism is different. The main bridging component for the PFR/PEO system was the PFR-PEO complex while for the pDADMAC/PFR/PEO system the bridging component was the PFR-PEO complek and the PEO itself. It was revealed that the optimum addition of coagulant further increased the fine retention and drainage when using PFR/PEO system.