Untersuchungen zur stofflichen Verwendung (English shop)

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The polyphenolic constituents of spruce bark can be obtained by extraction from the bark and used as an adhesive or as an adhesive component in the manufacture of wood-based materials. This has already been tested on an industrial scale. The present study deals, on the one hand, with the suitability of bark extracts obtained under various conditions as adhesives and, on the other hand, with the material utilisation of extracted spruce bark.

The investigations have shown that the yield of extracts and their reactivity towards formaldehyde can be increased by adding sodium hydroxide or urea during extraction.

Extraction with aqueous solutions at 130 °C alters the chemical and physical properties of the bark. This has a positive effect on its utilisation in horticulture as a substrate component. After extraction, less nitrogen is immobilised in the incubation test than in fresh bark, and the germination-inhibiting effect of the bark is largely eliminated by the extraction. In addition, lignin is enriched and the water capacity is increased.

The recovery of tannins from spruce bark and the utilisation of the extracted bark in horticulture represent a sensible combination. The concept enables a value-adding material use of bark.