Cross-Linked Gelatine as a Binder in Wood Fibre Composites for Topsoil Protection

This study aimed to develop novel sustainable composites based on cross-linked gelatine and wood fibres for use as a topsoil cover in forestry and agricultural applications. Different compositions were prepared by varying the proportions of gelatine, wood fibres, and tannic acid (the cross-linking agent). Water absorption analysis revealed that compositions containing 12% wood fibres exhibited the highest absorption values (300% after 24 h). Including wood fibres was crucial in limiting the cross-sectional shrinkage of the samples. Additionally, the wood fibres did not negatively impact the water vapour permeability values, which ranged from 0.5 to 3.5 × 10⁻⁸ kg/(Pa∙h∙m). Tensile tests revealed that the samples’ tensile strength ranged from 4 to 17 MPa, whereas Young’s modulus depended more on climatic conditions, with values reaching 2700 MPa in dry conditions and 300 MPa in wet conditions (samples conditioned at 20 °C and 95% relative humidity). Furthermore, after 46 weeks of outdoor exposure, the produced composites demonstrated good dimensional stability and reduced mass loss, particularly in the composition with the highest wood fibre and tannic acid content.