Multiple interactions constructed between cellulose chains and dye molecules via dye@polymer nanospheres for high-quality textile inkjet printing

Lyocell fabric, which is made of regenerated cellulose fiber, has become an important choice for low-carbon eco-textile manufacture owing to its pollution-free spinning process and excellent comfort. However, lyocell fabrics are generally colored by reactive dyes, which can cause high discharge of colored wastewater due to the poor interaction between dye molecules and cellulose chains. In response to the above challenge, a novel type of dye@polymer nanospheres was successfully synthesized, forming multiple interactions with cellulose chains through both covalent bonds and electrostatic forces. Dye molecules were fixed on polymer nanosphere surface, then the composite nanospheres were applied in digital inkjet printing of lyocell fabrics. From the transmission electron microscope measurement, the dye@polymer nanospheres possessed good monodispersity and regular spherical structure with a uniform size of about 120 nm. The thermal stability and crystallinity of dye@polymer nanospheres were characterized by differential scanning calorimetry, thermogravimetric analysis, and X-ray diffraction. The interaction between dye molecules and polymer nanospheres was determined through zeta potential analysis, Fourier transform infrared measurement and X-ray photoelectron measurement. Stable electrostatic force was formed between anionic dye molecules and cationic nanosphere macromolecular chains, causing those dye molecules to adsorb on the nanospheres in an amorphous form. From the color performance measurement of dye@polymer nanosphere printed patterns, the pattern outline, dye utilization efficiency, color strength and fastness were obvious improved in comparison to conventional inkjet printing using dye-based inks. Therefore, the method has great potential to enhance dye utilization efficiency in lyocell coloration and promote the lyocell development in eco-textile manufacture.