Open Access

REVIEW

Formation of Binder-Free Composites Based on Natural Materials: Structure, Mechanisms, and Prospects for Chemical Modification

Alexey E. Shkuro^1,*, Artyom V. Artyomov², Victor G. Buryndin², Anna S. Ershova², Tatyana V. Yakubova³

1 Higher School of Biotechnology, Ural State Forestry Engineering University, Yekaterinburg, Russia
2 Department of Pulp and Paper Production Technologies and Polymer Processing, Ural State Forestry Engineering University, Yekaterinburg, Russia
3 Ural Institute of State Fire Service of EMERCOM of Russia, Yekaterinburg, Russia

* Corresponding Author: Alexey E. Shkuro. Email:

(This article belongs to the Special Issue: Process and Engineering of Lignocellulose Utilization)

Journal of Renewable Materials 2026, 14(8), 2 https://doi.org/10.32604/jrm.2026.02025-0194

Received 16 October 2025; Accepted 24 June 2026; Issue published 26 August 2026

Abstract

Binder-free lignocellulosic boards and molded composites are gaining momentum as low-emission alternatives to conventional wood-based panels because they exploit intrinsic self-bonding of biomass under hot pressing. This review critically analyzes structure-formation pathways in binder-free composites, focusing on (i) thermo-mechanical softening and flow of lignin as a natural adhesive phase, (ii) auto-hydrolysis of hemicelluloses generating organic acids and reactive furanic intermediates, and (iii) subsequent condensation and crosslinking reactions that consolidate the network. We compare process routes historically associated with Masonite-type fiber processing and Lignoplast-type direct compaction, highlighting how moisture, temperature, pressure, sealing degree, and particle morphology govern bond development and dimensional stability. Particular attention is paid to chemical activation strategies (oxidants, nitrogen-containing reagents, and reactive bio-based systems) that tune lignin mobility and reactivity, enabling milder pressing and improved water resistance. We outline research gaps linking chemical transformations to macroscopic performance, and propose future directions including in situ monitoring, quantitative structure-property models, and activation chemistries compatible with circular and compostable product concepts.

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Keywords

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