Do production processes influence the mechanical properties of bleached alfa pulpboard?

Abstract

This study was conducted to determine and analyse the influence of production process on the mechanical properties of bleached alfa pulpboard. Scanning electron microscopy showed that the industrial process currently used to produce the pulpboard causes small-scale and large-scale deformations in the alfa fibres. The same process results in a preferred orientation of the alfa fibres, leading to alignment in the rolling direction and hence there is some variation in the mechanical performance of the pulpboard in the different directions. Indeed, the mechanical properties show that the pulpboard loses its isotropic nature, mainly in the high-deformation regions. The pulpboard does not have the same mechanical characteristics in the longitudinal, 45°, and transverse directions. The samples taken in a longitudinal direction, which corresponds to the rolling direction, have better mechanical performance than in samples taken in the other two directions. Furthermore, the alkali (NaOH) treatment that is used to extract the alfa fibres from the alfa stems did not succeed in removing all of the non-cellulosic materials initially present in the alfa stems.