Abaca as a reinforcement fiber for softwood pulp

Abstract

We investigated the affect on paper strength properties of adding a neutral sulfite abaca pulp to a softwood kraft pulp. Standard isotropic laboratory handsheets were made, and sheets were also made in a dynamic sheet former. The pure abaca pulp had higher tear and tensile indices for a given refining energy than the softwood pulp. The addition of abaca to the softwood pulp increased the tear strength, fracture toughness, and folding endurance for the isotropic sheets. The tensile stiffness of isotropic sheets was independent of the abaca content, but the tensile strength decreased slightly with increasing abaca content, perhaps because the addition of abaca led to a decrease in density. The anisotropic sheets showed the same trends as the isotropic sheets. Tearing resistance and fracture toughness increased with the addition of abaca. Tensile strength and tensile stiffness were only slightly affected by the addition of abaca, but the geometric mean values for the pure abaca sheets were slightly higher than those of the pure softwood sheets.