SCIENCE@home

Changes in water-vapor-adsorption isotherms of pulp fibers and sheets during paper recycling, including drying of wet webs, and disintegration and sonication of dried sheets in water

M. Kimura,M. Takeuchi,Akira Isogai

Published 2023 in Nordic Pulp & Paper Research Journal

ABSTRACT

Abstract A never-dried (ND) fines-free softwood bleached kraft pulp was converted to air-dried and thermally dried handsheets, which were then disintegrated or sonicated in water under various conditions. These disintegrated or sonicated pulps were converted to handsheets and used to obtain fundamental data on paper recycling. The water-vapor-adsorption isotherms of the pulp and sheet samples after super-critical-point drying showed clear differences between the water volumes adsorbed by the ND pulp, once-dried pulp, and dried sheets at the same relative humidities above 50%. These differences are caused by hornification of the pulp and sheet samples during drying and recycling. Air and thermal drying of wet webs decreased the adsorbed-water-vapor volume by 7%–9% and 14%–18%, respectively, relative to that adsorbed by the original ND pulp. We hypothesize that the decrease in water-vapor-adsorption volume from that of the original ND pulp at relative humidities >50% reflects the degree of irreversible formation of hydroxyl groups in the originally hydrophilic hemicelluloses and crystalline cellulose microfibril surfaces in the pulp and sheet samples during drying and paper recycling. The water-vapor-adsorption isotherms of pulp and sheet samples can be used to quantify the degree of hornification or the amount of irreversible hydrogen bonds formed during paper recycling.

PUBLICATION RECORD

CITATION MAP

EXTRACTION MAP

CLAIMS

  • No claims are published for this paper.

CONCEPTS

  • No concepts are published for this paper.

REFERENCES

Showing 1-25 of 25 references · Page 1 of 1

CITED BY

  • No citing papers are available for this paper.

Showing 0-0 of 0 citing papers · Page 1 of 1