Eco-friendly reactive inkjet printing on cotton fabrics post-treated with aminopropyl/vinyl/silsesquioxane
Osama A. Hakeim, Hanan A. DiabPurpose
Conventional reactive inkjet printing on cotton uses high quantities of salt, urea and alkali, which requires energy-intensive steaming fixing and produces highly polluting effluents. The purpose of this study is to create an environmentally friendly, auxiliary-free technology that uses aminopropyl/vinyl/silsesquioxane (APS) post-treatment to produce effective fixation at a low energy cost while limiting environmental impact.
Design/methodology/approach
Cotton fabrics were printed with CMYK reactive inks and then treated with APS solution (7.5% w/v, pH 10) by thermal (sodium persulfate, 60–80°C) or UV (DEAP photoinitiator, 365 nm, 3 min) curing. Fixation efficiency, color strength (K/S), CIE Lab* coordinates, fastness characteristics, effluent COD, tensile strength, flexibility, FTIR and SEM were all measured and compared to conventional steaming.
Findings
APS post-treatment under UV curing achieved near-quantitative dye fixation (DF% 95%–98%), significantly outperforming conventional steaming (80–88%) and thermal curing (92%–94%). UV-cured samples exhibited superior color strength (K/S up to 32 for black reactive ink), deeper shades (lower L*), and higher chromatic saturation across all CMYK colors, with K/S gains of 48–109% over conventional steaming. Wash and crocking fastness ratings reached 4–5, and light fastness 5–7 (1–8 scale). Effluent COD was reduced by approximately 65%–70% (to ∼40 mg/L versus ∼120 mg/L for conventional), while tensile strength was marginally enhanced (465 ± 7 N) and fabric flexibility significantly improved (bending length 2.5 ± 0.2 cm). ATR-FTIR and SEM confirmed homogeneous APS grafting and successful UV-initiated vinyl crosslinking on the cotton fiber surface.
Research limitations/implications
This study is conducted at laboratory scale; translation to industrial production introduces several practical challenges. Continuous UV curing systems must be engineered to deliver uniform irradiance across fabric widths exceeding 1.5 m, and padding uniformity must be maintained under variable fabric tensions in continuous processing lines. The long-term colloidal stability of APS aqueous dispersions under storage conditions typical of textile mills including temperature fluctuations (5°C–40°C), prolonged shelf-life exceeding 6 months and exposure to hard water has not yet been systematically evaluated and represents an important prerequisite for industrial adoption. Furthermore, the current findings are specific to plain-weave cotton fabric printed with CMYK reactive inks; applicability to other fabric constructions (viscose, cotton/polyester blends), additional reactive dye chemistries (vinylsulfone, bifunctional) and other printing resolutions requires further systematic investigation.
Practical implications
APS post-treatment is a simple, low-energy alternative to traditional auxiliaries that allows textile mills to minimize chemical use, wastewater treatment expenses and energy consumption while preserving or increasing print quality and fabric handling. It is compatible with current inkjet printers and ideal for short-run, on-demand printing.
Originality/value
While APS has previously been demonstrated by the group as a post-treatment agent for pigment-based inkjet printing on polyester fabrics achieving low-temperature UV or thermal fixation, enhanced color strength and antistatic properties, its application to reactive dye fixation on cotton cellulose represents a fundamentally new extension of this chemistry. Unlike pigment printing, which relies on physical film encapsulation, reactive inkjet printing on cotton requires covalent bonding between the reactive dye and cellulose hydroxyl groups, demanding a controlled alkaline environment (pH 9–11) and suppression of competitive dye hydrolysis. To the best of authors’ knowledge, the present study is the first to demonstrate that a single APS post-treatment step can simultaneously fulfill the roles of cationising agent, pH buffer and crosslinking matrix to achieve near-quantitative reactive dye fixation on cotton without conventional salt, urea, or alkali auxiliaries.