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Extraction of polyphenolic substances from bark as natural colorants for wool dyeing
Author(s) -
FitzBinder Christa,
Bechtold Thomas
Publication year - 2019
Publication title -
coloration technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.297
H-Index - 49
eISSN - 1478-4408
pISSN - 1472-3581
DOI - 10.1111/cote.12378
Subject(s) - dyeing , mordant , wool , pulp and paper industry , bark (sound) , polyphenol , extraction (chemistry) , chemistry , textile , aqueous solution , raw material , textile industry , materials science , chromatography , organic chemistry , composite material , forestry , engineering , antioxidant , geography , archaeology , history
In Europe, considerable amounts of bark are available from wood‐processing industries such as forestry and timber production. Polyphenolic components can be collected by hot water extraction. The extracted compounds can then be applied as colorants in textile dyeing operations. In this study, a comparative assessment of four different tree species with regard to their colouristic potential for wool dyeing was performed. Aqueous extracts from alder, ash tree, spruce and oak bark were prepared and analysed for their total phenolic content and ultraviolet ( UV ) absorption at 360–370 nm. The extracts were used for meta‐mordant dyeing by adding iron sulphate mordant (Fe SO 4 × 7H 2 O). For comparison, iron salt‐based dye lakes were prepared and used in dyeing experiments. For each tree species, a specific correlation between the total phenolic content of the dyebath and the colour depth in terms of K / S and CIEL ab coordinates was observed, both for the aqueous extracts and the dye lakes. Based on this relationship, standardisation and quality control of raw materials and dye lakes can be installed as important stages in the industrialisation of natural colorants from bark. The preparation of concentrated dye lakes permits formation of a concentrated colorant as dye product, which then can be standardised and delivered to textile dyehouses, similar to synthetic dyes. The preparation of dye lakes offers a relevant route towards achieving the commercialisation of bark extracts as natural colorants.