SURVEY OF POTENTIAL RETENTION AIDS FOR NEWSPRINT MANUFACTURE.

Among 17 polymer evaluated as retention aids for fines in newsprint manufacture, a high-molecular weight poly(oxyethylene) (PEO), was the most cost effective. Eighty percent first-pass retention was observed at 0. 04% PEO, whereas 0. 14% of a solid, high molecular weight, cationic poly(acrylamide), the next most cost effective retention aid, was required for the same performance. The effectiveness of the polymers was decreased with increasing amounts of hydrodynamic shear. All low-molecular weight cationic polymers tested, including a poly(ethyleneimine), were ineffective at concentrations of possible commercial interest. The PEO reduced the concentration of colloidal pitch in the white water and had no effect on the physical properties of handsheets. Both the PEO and a cationic poly(acrylamide) increased freeness at concentrations which increased fines retention.