Novel Approach to Dye Polyethylene Terephthalate (PET) Fabric in Supercritical Carbon Dioxide with Natural Curcuminoid Dyes

Abstract

The use of natural dyes has increased in the last few decades due to the eco-friendly approach of dyeing. There are still some limitations that are associated with natural dyes, such as dyeing efficiency, reproducibility of shades, process complexity, availability etc. The main problem associated with the dyeing property of natural dyes is “low exhaustion”. In this study, natural dyestuff from Curcuma longa L. was extracted and polyethylene terephthalate fabric was dyed with it in the same bath by employing the supercritical carbon dioxide method. The method was developed to improve the dye-ability of natural dyes and reduce the process time and effluent. Curcuminoid dye exhaustion on PET fabric showed almost 80% by using supercritical carbon dioxide dyeing methods, and the highest colour strength (K/S = 12) was obtained. Coloured polyethylene terephthalate fabric treated with supercritical carbon dioxide showed deeper shades (L* = 72.92) and better fastness properties as compared with high temperature exhaust dyeing methods.

Recent advances in supercritical fluid dyeing

“…1,4,13,[24][25][26][27][28] However, laboratory-scale investigations 18,[29][30][31][32] or simulation studies 33 aimed at disclosing other aspects of the process mechanism have also been conducted, as well as tests with natural or new synthetic dyestuffs. [34][35][36][37] 2.1 | Recent technological advances (2014- Table 1 provides an overview of some recent laboratory to industrial-scale prototypes and innovative technological solutions for SFD of PET. All entries reported refer to research conducted in China, which reflects its economic growth and industrial development in the last decade.…”

“…These may be newly synthesised anthraquinone 34 or azo dyes 35 as well as natural compounds. 36,37 Researchers have reported many different reasons to search for novel dyes, such as the enlargement of the number of supercritical carbon dioxide-soluble dyes, 35 their synthesis from commercially inexpensive starting materials 34 or the employment of hypoallergenic molecules. 36,37 Other innovative purposes are the use of special dyes to impart anti-bacterial, fluorescent or photochromic properties to the textile, which is discussed in section 5.…”

“…Among the above-cited works, perhaps the most promising and up-to-date research is that connected to the use of hypoallergenic natural colorants. 36,37 The application of these natural compounds on synthetic textiles via conventional aqueous methods requires appropriate surface pretreatment of the fibre and the use of mordant chemicals, which may limit the cost-effectiveness and benefit of a low environmental impact. 36 For this reason, the use of supercritical carbon dioxide represents a viable alternative.…”

“…36 Coloration of PET fabric with natural curcuminoid dyes was also achieved with an innovative approach by another research group. 37 This was performed by the simultaneous extraction of curcuminoid dyes from turmeric and PET dyeing in the same supercritical bath. The turmeric powder at different dosages was directly poured into a dyeing autoclave, which also contained the PET fabric, and dyeing was performed at 150°C and 20 MPa for 1 hour.…”

“…The authors explained that, under the influence of light, the curcuminoid dyes were probably converted from a keto to an enol form, which could result in their sublimation from the fabric surface. 37 3 | SUPERCRITICAL FLUID…”