Comparison of Chitosan Performance in a Single or Nanoparticle System as a Wet End Additive in Recycled Printing and Writing Papers

To compensate for some inferior properties of recycled papers, application of processing chemical aids such as chitosan can be quite effective in the wet end section of papermaking. In this study, the performance of chitosan biopolymer, individually or associated with nanobentonite was investigated as wet end additive on recycling process of white cuttings. For this purpose, the performance of this biopolymer at 0.5, 1, 1.5 and 2% (based on oven-dried pulp) were compared in a single polymer system or with nanobentonite. The results revealed that dosing different amounts of chitosan resulted in increasing tensile, tear and burst indices. Moreover, improvement in first pass retention (5 and 10% in single and nanoparticle system, respectively) and drainage (18.75 and 23.5% in the case of single and nanoparticle system, respectively) was observed, while the improvements resulted from nanoparticle system was more prominent according to the wet end parameters. It is noteworthy that increase in strength properties in presence of bentonite nanoparticle was unexpected, and on the other hand the more additive used, the more gains in paper strength properties and processing parameters was detected.