Effect of pH and conductivity in weak polyelectrolytes multilayering on paper properties

Pulp fibers can be modified through a Layer-by-Layer polyelectrolyte multilayering process. The properties of pulp fibers are affected by the multilayering conditions including the conductivity and pH of the aqueous solution. In this study, we evaluated the properties of the handsheets made of multilayered fibers with weak polyelectrolytes at different pH and conductivity levels. We prepared handsheets from modified pulp fibers by means of multilayering with polyallylamine hydrochloride and polyacrylic acid and evaluated their bonding ability and structural properties. The bonding ability of the fibers was improved remarkably after the polyelectrolyte multilayering due to the increased conformability and electrostatic bonding between the polycation and polyanion on the fiber surface. An outstanding increase of the tensile index was observed at pH 10 when the pulp fibers were treated by polyelectrolyte multi layering. The sheet thickness increased depending on the pH condition. The formation of the paper deteriorated slightly after the polyelectrolytes multilayering process.