Bio-based polymer colorants from nonaqueous reactive dyeing of regenerated cellulose for plastics and textiles.
A general way to prepare bio-based polymer colorant by reactive dyeing of regenerated cellulose (RC) in dimethyl sulfoxide (DMSO) was established. Up to 40% higher dye utilization was achieved compared with aqueous reactive dyeing of RC for two reasons. 1. Lower liquor ratio of 1:9 could be applied for the concentrated RC suspensions in DMSO was less viscous. 2. Dye loss from solvolysis was turned off in DMSO. The method was generally applicable to RCs made from wood pulp, waste cotton, and bamboo pulp. The dyeing process has minimum influence on the morphological, rheological, and thermal properties of RC. The colored RCs thus prepared were used to prepare colored polymer composites via a Pickering emulsion approach, and to color cotton, cotton blend, and viscose fabrics via a printing approach. Therefore, it holds great potential as renewable and biodegradable pigments for making colorful composites, ink, textile dyeing and finishing.