Differences in the physicochemical properties of lignins in the heartwood and sapwood of Pinus sylvestris

Abstract

Lignin polymers are among the main components of the cell wall and characterized by the highest reactivity due to their polyfunctional nature, the presence of reactive centers and a conjugated polymolecular aromatic structure. Investigation of differences in functional composition, macromolecular, reaction and electrophysical properties of slightly altered preparations of dioxane lignin extracted from the heartwood and sapwood of pine was carried out in this paper. The increased content of carboxyl groups in the heartwood lignins leads to a decrease in the reaction (acid-base and redox) properties and specific electrical conductivity. Changes in the physicochemical properties of lignins in the wood matrix indicate the continuous transformation of the natural polymer during the life cycle of plants.

Keywords:

• Heartwood
• sapwood
• lignin
• phenolic hydroxyl groups
• dielectric permittivity

Acknowledgments

The authors are grateful to Dr. Krasikova A.A.

Additional information

Funding

This research was funded from the project agreement No. AAAA-A18-118012390231-9. Instrumentation of the Core Facility Center “Critical technologies of the Russian Federation in the field of environmental safety of the Arctic” (N. Laverov, Federal Center for Integrated Arctic Research) was used in this work.