Upgrading of recycled paper with oil palm fiber soda pulp

Recycled fibers, in comparison to its virgin counterpart, generally have reduced conformability and interfiber bonding capability due to irreversible hardening or hornification of these fibers. The extent and reversibility of the reduction is dependent on the original pulp type and on the papermaking process. Various methods are used to recover the lost potentials of the recycled pulp such as mechanical beating, use of chemical additives, physical fractionation and blending; the latter being the subject of this study using oil palm fiber virgin soda pulp as the upgrading strength material. With as little as 20% addition of virgin unbeaten pulp and considerably lesser amount of ca. 10% of beaten virgin pulp is sufficient to completely restore the strength of the recycled paper. The major mechanism of strength improvement is probably due to increase of interfiber bonding as a result of substitution of inactive secondary fibers with active virgin fibers.