The majority of current textile fibres are produced from oil-based raw materials and thus have a role in challenges related to global warming and microplastic generation. This has created an opportunity to increase the production of cellulose-based man-made fibres, and consequently boost the development of novel technologies in the field of cellulose dissolution and regeneration as well as utilization of recycled cellulosic materials.
A great advantage of future cellulosic fibres is the possibility to endow special characteristics such as enhanced dyeability, flame retardancy, antimicrobial, hydrophilic and hydrophobic properties. This reasserts the role of cellulosic fibres as replacement for the existing oil-based fibres. The specific properties can be obtained by introducing the desired functionality into the textile fibres or structure by prior modification. The resulting functionality is permanent and allows to reduce the formation of toxic filtrates and spent solutions in further processing, e.g., in dyeing. The FinnCERES-funded project Functionalized Biocelsol Fibres (Funcbiocelsol) is looking into these types of functionalities.
Basic principles for functional cellulosic fibres
In FuncBiocelsol project, fibres are produced using a novel Biocelsol technology in which hazardous chemicals in cellulose treatment are replaced with ecologic enzymes. After the enzymatic activation, the cellulose is further modified with mild chemicals at moderate conditions to incorporate reactive double bonds in the structure. Such treated cellulose is dissolved in water-based environment and regenerated into cellulosic fibres by a wet-spinning technique. The reactive sites are incorporated in the fibre structure to be utilized for attaching desired functional groups before or after the typical textile-making processes.
Figure: Processing steps for functional cellulosic fibres
A clear benefit of the Biocelsol process compared to the widely used viscose process is the lack of toxic carbon disulphide, and the benefit of FuncBiocelsol process is the permanent reactive sites for durable functionality.
Achieved and proven properties
So far, we have shown high processability of chemically modified cellulose in dissolution and wet-spinning for FuncBiocelsol. Development in fibre strength has been very promising and the properties are approaching commercial viscose fibres. The fibres produced from wood cellulose have high brightness and exceptionally good adsorption capacity.
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