Nanocellulose addition to recycled pulps in two scenarios emulating industrial processes for the production of paperboard

Abstract

This study assesses the incorporation of nanocellulose in a paperboard feedstock emulating two scenarios of industrial processes. It included the production of 170 g/m2 paperboard, using mixtures of short-fiber and long-fiber fractions from recycled pulps with typical mill additives. In all cases, 3 wt. % of nanocellulose was added to the pulp suspensions. The first scenario involved three types of nanocellulose addition in a mixture of 78 % long-fiber/22 % short-fiber pulps. The second scenario included the addition of two types of nanocellulose to an unrefined long fiber pulp to produce a multilayer paperboard. Drainage time and physical-mechanical properties of the handsheets were evaluated. Nanocellulose improved the mechanical properties in all cases. The tensile and burst indexes increased 19 % and 28 % in Scenario 1 and up to 60 % and 43 % in Scenario 2, respectively. The lower values in mechanical properties for Scenario 1 were attributed to the effect of the retention system. A new retention system using a cationic polymer with a high charge density produced decreases up to 79 % in the drainage time.