We thoroughly studied the resistance of tannin-based foams from the bark of conifers against fungi. We prepared 4 different structures of tannin foams. Foam samples were sawn of hardened tannin-based foams; then their dimensions and weight measured. Foam samples were infused in distilled water for 3 days, and dried to an absolute dry condition (103 °C, 24h). Their dimensions and weight were re-measured; the density of foams was calculated before and after soaking. After the soaking and drying the mass of the foam samples halved; while the volume after the drying decreased by a third. In petri dishes, a habitat for fungi was prepared, fungi inoculated, and after a week the samples made of foams and wood exposed to fungi for 8 weeks. We used one brown rot fungus (Gloeophyllum trabeum) and one white rot fungus (the oyster mushroom, Pleurotus ostreatus). After the explosion mycelia were cleaned out of the samples and weighted. The samples then dried to an absolute dry condition, and re-weighted. From the data obtained before and after the exposure to fungi, the mass loss was calculated. We ascertained that tannin-based foams from the bark of conifers were resistant to wood fungi, because the loss of mass compared to the wood samples was much smaller.
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