Modified chitosan pretreatment of polyester fabric for printing by ink jet ink

The present research deals with the use of pretreatment solutions of chitosan (CH), N-[(4-dimethyl aminobenzyl)imino] chitosan (DBIC), N-[(2-hydroxy-3-trimethylammonium)propyl] chitosan chloride (HTACC), glycine (Gly), and a mixture of CH and Gly, for padding polyester fabrics prior to printing with a set of seven-color pigmented water-based ink jet inks. After padding the fabrics with the above cationic pretreatments, they were printed with a piezo-electric drop-on-demand jet printer. CH, DBIC and HTACC were characterized by IR and NMR spectroscopy. The zeta potentials of the pretreatment solutions, the inks and the fabrics were measured. The K/S values, color gamut, tone reproduction, outline sharpness, and the surface appearance of the fabrics were characterized. Statistical evaluation of the significance of the results was performed. Among the pretreatments, the HTACC at 0.1% (w/v) yielded fabrics with the highest K/S values, widest color gamut and gamut volume, more color saturation with good tonal reproduction, and the sharpest and smoothest outline of printed character, and a smooth fabric surface with less stiffness. The proposed ionic interactions between the protonated amino groups of CH and the anionic portion of the encapsulated ink pigments, and van der Waals and hydrophobic interactions between the polyester and the pigments are likely reasons for these enhanced properties of the printed fabrics.