Decamethylcyclopentasiloxane-based sustainable and recyclable polyester fabric whitening using OB-1 fluorescent brightener

Fluorescent whitening agent OB-1 (OB-1) has non-toxicity, chemical stability, exceptional heat resistance, and light stability, and it is widely used in plastic products. However, raw OB-1 is difficult to apply in textiles by exhaustion process. The present investigation employed raw OB-1 without adding an auxiliary to bestow a whitening effect on polyester fabric in a sustainable medium of decamethylcyclopentasiloxane (D5). The Taguchi methodology was employed to optimize the whitening parameters. An L16 orthogonal array was utilized to investigate the optimal conditions for whitening temperature, whitening time, and OB-1 mass, with four whiteness levels. The signal-to-noise ratio was optimized using a larger-is-better approach to enhance the parameter responses. The study analyzed the main effect and interaction plot of multiple factors. The findings indicate that the temperature of the whitening process significantly impacts the whiteness of the polyester fabric (P < 0.05), with a 98.4 % contribution percentage. Under the optimal conditions, a whiteness value of 109.9 was observed for the polyester fabric. Subsequently, various analytical techniques, including FT-IR, SEM, TGA, and XRD, were employed to characterize the treated fabric. The results indicate that using D5 medium was viable for whitening polyester fabric. The study also examined the duration of washing and rubbing to determine their whitening performance. The study evaluated the whitening efficacy of polyester fabric treated with recycled D5 medium and demonstrated its potential for application at the pilot scale in the textile sector.