Determination of the cellulose and lignin content on wood fibre surfaces of eucalypts as a function of genotype and site

Abstract

We compared the chemical composition of wood fibres and fibre surfaces of several eucalypt species and hybrids originating from various growth sites in South Africa. The objective was to test for differences in chemical surface composition due to genetics or site with the ultimate aim to facilitate a tailor-made supply of wood for pulping that results in an optimal blend of fibres that can be pulped together with similar yields. This, however, requires a sound knowledge of the fibre properties. The surface functionality on the single fibre level is a key property, because it determines how good inter-fibre bonding will be when paper is formed, which depends amongst other fibre properties on the amount of free hydroxyl groups that are available and therefore on the cellulose content on the fibre surface. The cellulose and lignin content on the fibre surface were determined with chemical force microscopy, a variation of atomic force microscopy. Since the general bulk composition of the fibre and the surface composition might differ, both parameters were determined. We found significant differences in the cellulose and lignin content on fibre surfaces, with regard to genotype and site, respectively. In some, but not all, cases, the surface composition of wood fibres followed the bulk composition, and differences were generally more pronounced. Differences due to genotype were significant, especially with regard to the surface lignin content-but variation due to site was also distinctly recognisable. This variation in surface functionality could be the reason why some pulpwood blends result in a lower pulp yield and different quality.

Characterisation of the Interfacial Adhesion of the Different Components in Wood–Plastic Composites with AFM

“…In a related study, Vancso et al [94] reviewed the recent developments in the field of highresolution lateral mapping of the surface chemical composition of polymers by AFM and other complementary imaging techniques to unravel the lateral distribution of chemical surface groups, the stability of various types of functional groups in various environments and the interactions with controlled functional groups at the tip surface. Springer Science Reviews Figure 4 shows the quantified adhesive forces detected in air between different functionalized tips and different wood components [45].…”

“…Klash et al [45] studied the distribution of different free chemical functional groups on wood and pulp fibres by means of CFM with chemically modified tips, which showed different sensitivities towards the major functional groups present in the different wood components. The cellulose and lignin content on fibre surface was thus not only localised, but could also be quantified [46].…”

“…The deflection of the cantilever spring is directly proportional to the tip-sample interaction Fig. 4 Adhesive forces determined between the different substrates and a -COOH-, b -CH 3 -and c -OH-coated tips [45] Springer Science Reviews force, and once the deflection of the cantilever is known as a distance x, the adhesive force F can be calculated with Hooke's law:…”

“…Adhesive force images and histograms of grey values obtained on the fibre surface of pulped E. grandis with a -COOH-and b -CH 3 -coated tips and on the fibre surface of pulped A. mearnsii with c -COOH-and d -CH 3 -coated tips, showing the removal of lignin on the fibre surfaces[45] …”

Production of low cost paper from Pandanus utilis fibres as a substitution to wood

“…An increase in moisture in the paper might cause curling, printing troubles and bad quality paper. are formed in between the fibres which are responsible for good physical and mechanical properties of the final product [22].…”