Effect of Supercritical Carbon Dioxide on Dyeability and Physical Properties of Ultra-High-Molecular-Weight Polyethylene Fiber

Abstract

Supercritical carbon dioxide dyeing, a new type of anhydrous dyeing method, has a lot of advantages, mainly conservation of energy, prevention of pollution, reusability of dye, and many more. This study presents a viable method for the dyeing of an ultra-high-molecular-weight polyethylene (UHMWPE) fabric by using supercritical carbon dioxide (scCO2) as a medium. Five hydrozono propanenitrile dyes that are functional colorants having antibacterial activity were applied for the dyeing of the UHMWPE fabric in scCO2 at a pressure of 20 MPa and at temperature of 120°C. The dyeability of UHMWPE fabric under scCO2 was evaluated by color measurement, whereby the color strength K/S was calculated. As the treating time and concentration of dye increased, the dyeability of the UHMWPE fabric displayed the tendency to continually improve. As decaline was added into scCO2 as the cosolvent, we obtained higher K/S. Furthermore, color fastness to rubbing and sublimation of the dyed UHMWPE fabric were determined according to Japanese Industrial Standards (JIS) L 0849 2 and JIS L 0854, and the trend showed that the increase in fastness corresponded to the increase in duration of the treatment. The influence of scCO2 dyeing on the mechanical properties of UHMWPE was also examined. Consequently, it was found that dyeing in scCO2 containing decaline reduced the crystallinity of the UHMWPE fabric and the breaking strength decreased. The antimicrobial property of UHMWPE dyed with N′-(2-chloro-4-methylphenyl)-2-oxo-2-(p-tolyl)acetohydrazonoyl cyanide was tested against three different microorganisms, and the results have been reported.

Supercritical Fluid Applications in the Design of Novel Antimicrobial Materials

“…Textile dyeing with antimicrobial dyes [44][45][46], proven to be feasible using SSI, is promising for industrial production since the scale-up for this technology is known. Presented antibacterial properties of the obtained products as well as the existing needs for the added-value medicinal textiles ensure their wide applications.…”

“…The color strength increased with the treating time as well as with the addition of decalin as a cosolvent. The fibers obtained showed antibacterial activity against E. coli, S. aureus, and B. cereus [46].…”

“…Obtained fabrics exhibited antibacterial activity against E. coli, S. aureus, P. aeruginosa, and B. subtilis [45]. In the next study [46], Ma et al presented viable dyeing of ultra-high-molecular-weight polyethylene (UHMWPE) fabric in scCO 2 at a pressure of 20 MPa and temperature of 120 • C for 1-3 h. Five hydrozono propanenitrile dyes having antibacterial activity were applied. The color strength increased with the treating time as well as with the addition of decalin as a cosolvent.…”

Recent advances in supercritical fluid dyeing

“…45 Ultra-high molecular weight polyethylene (UHMWPE) is another hard-to-be-dyed material due to its high crystallinity and dense molecular structure, which make it difficult for the polymer to interact with the dyes. 47 The same anti-bacterial hydrazonopropanenitrile disperse dyes that were used to dye nylon 6 44 were used to achieve supercritical fluid coloration of UHMWPE. 47 Satisfactory coloration could be achieved when decalin, which is a paraffin oil previously employed for gel-spinning of UHMWPE, 48 was added as a co-solvent.…”

“…47 The same anti-bacterial hydrazonopropanenitrile disperse dyes that were used to dye nylon 6 44 were used to achieve supercritical fluid coloration of UHMWPE. 47 Satisfactory coloration could be achieved when decalin, which is a paraffin oil previously employed for gel-spinning of UHMWPE, 48 was added as a co-solvent. However, the combined plasticising/swelling action of supercritical carbon dioxide and decalin promoted reorientation of the polymer chains, which resulted in a strong reduction of the degree of crystallinity (from an initial value of 90%, it was reduced to 60%-70%).…”