New impregnation materials and usage scale in ecological restoration

The ecological environment has made various contributions to the maintenance of human life for centuries. Mussel shell extract (Chamelea gallina) as a natural impregnation agent on the physical, mechanical, and thermal properties of mahogany (Swietenia mahagoni) and larch (Larix decidua) woods. Solutions at 2%, 4%, and 6% concentrations were applied by immersion for 30 minutes, 6 hours, and 24 hours. After impregnation, density, retention, compression strength, bending strength, and modulus of elasticity were measured, while thermal behavior was examined through thermogravimetric analysis (TGA). Results indicated that larch exhibited a significantly higher absorption capacity than mahogany, yielding more pronounced improvements in physical and mechanical properties. Treatments at 4% and 6% concentrations produced the best outcomes in larch, with maximum retention of 35,44 kg/m³, an oven-dry density of 0.75 g/cm³, and enhanced strength properties. In contrast, mahogany showed adverse effects on certain mechanical characteristics, particularly modulus of elasticity, under long-term and high-concentration treatments. TGA analyses revealed that mahogany started to degrade above 320 °C, whereas larch began around 298 °C. Mussel shell extract raised the onset degradation temperatures and increased the residual inorganic content at 550 °C, demonstrating the contribution of CaCO₃ to char formation. Overall, the findings highlight mussel shell extract as a bio-based, eco-friendly impregnation material, offering effective protection especially for larch in structural applications. As an organic and sustainable alternative, it shows potential for replacing conventional chemical preservatives and may be applied in both interior and exterior components of historical wooden structures. Keywords: Impregnation, Dipping, Mussel shell, Mahogany, Larex, Wood technology