Stabilization of natural and synthetic indigo on nanocellulose network - Towards bioactive materials and facile dyeing processes

dc.contributorAalto Universityen
dc.contributor.authorLohtander, Tia
dc.contributor.authorDurandin, Nikita
dc.contributor.authorLaaksonen, Timo
dc.contributor.authorArola, Suvi
dc.contributor.authorLaaksonen, Päivi
dc.contributor.departmentBioproduct Chemistry
dc.contributor.departmentTampere University
dc.contributor.departmentVTT Technical Research Centre of Finland
dc.contributor.departmentHäme University of Applied Sciences
dc.contributor.departmentDepartment of Bioproducts and Biosystemsen
dc.description.abstractSynthetic dyes are vastly used for colouring numerous materials, although the adverse effects on environment are well recognized. In addition to developing the existing dyeing technologies more efficient and cleaner, the valorisation of natural dyes can enhance the sustainable development of dyeing industry. Natural indigo, derived from Isatis tinctoria, is a bio-based alternative for indigo produced via chemical synthesis routes. Owing to the insoluble character of indigo pigment, the dye requires conversion into soluble leucoindigo form prior to dyeing, which is often accomplished by using harsh sodium dithionite vat technique. During the processing from plant to dye attached on a fabric, indigo is transferred from the soluble leucoindigo form to the oxidized insoluble indigo and once more back to leucoindigo. Additionally, the oxidation is difficult to control and with traditional vat technique maintaining the leucoindigo through the dyeing often requires adding more reducing agent chemicals. Maintaining the soluble form throughout the process would enable lower number of processing steps and reduce the use of harmful chemical agents. In the present study, the stabilization of leucoindigo on nanocellulose matrix carrier was investigated with spectroscopic and photophysical methods. According to the results, leucoindigo was successfully stabilized on nanocellulose suspension, most likely due to the limited rate of oxygen diffusion into the viscous medium. Visual observations revealed that the leuco-form was retained even longer with natural indigo than synthetic indigo. This enhanced stability was attributed to the presence of radical scavenging species in natural indigo since the synthetic indigo did not show notable antioxidant properties. Given the promising results the paste formulation was demonstrated to be applicable for creating patterns on cotton using a screen-printing technique. Since the leucoindigo was stabilized on nanocellulose carrier, the need for re-reduction prior to dyeing was avoided and the amount of harmful reducing chemicals was reduced. These findings also show that the characteristics of natural dyes that are often considered disadvantageous compared to synthetic dyestuff, i.e. presence of co-products in the mixture, can however, create more value to the dyed material through new functionalities.en
dc.description.versionPeer revieweden
dc.identifier.citationLohtander , T , Durandin , N , Laaksonen , T , Arola , S & Laaksonen , P 2021 , ' Stabilization of natural and synthetic indigo on nanocellulose network - Towards bioactive materials and facile dyeing processes ' , Journal of Cleaner Production , vol. 328 , 129615 .
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dc.publisherELSEVIER SCI LTD
dc.relation.ispartofseriesJournal of Cleaner Productionen
dc.relation.ispartofseriesVolume 328en
dc.titleStabilization of natural and synthetic indigo on nanocellulose network - Towards bioactive materials and facile dyeing processesen
dc.typeA1 Alkuperäisartikkeli tieteellisessä aikakauslehdessäfi