Abstract
The application of functionalized polyacrylamide derivatives to paper strengthening agent (PSA) has gained wide acceptance by paper industry. The popular system of using these derivatives is the dual polymer system. In this system, the anionic-polyacrylamide is added to the pulp suspension after or before the addition of cationic-polyacrylamide. Recently, due to the effective utilization of recycled paper and the demand of various paper qualities, the PSA is required the quality improvement and more effective application. To satisfy these requirements, we established the new system of paper strength development, that is, the anionic-polyacrylamide and cationic -polyacrylamide mixing system. In the mixing system, different from the dual polymer system, the polyion complex is firstly made by mixing of anionic-polyacrylamide and cationic-polyacrylamide. Then, this mixed solution is added to the pulp suspension after the alum addition. Comparing with the conventional dual system, the mixing system gives much more improvement of pulp retention and paper quality. The investigation and application of the mixing system have been summarized.
