Weight reduction of polyester fabric using sodium hydroxide solutions with additives cetyltrimethylammonium bromide and [BMIM]Cl

Abstract

Polyethylene terephthalate (PET) fibre is largely used in the textile apparel industry. Treatment of PET fibres by sodium hydroxide solution is a well-known process giving smooth surface with decrease in the fibre diameter. Hydrolytic scission of ester linkages of the polyester chains on the fibre surface takes place. Appropriate effects are achieved through monitoring of alkali concentration, time and temperature of the process without any significant deterioration of important fibre characteristics. Addition of various chemicals enhances the hydrolytic action of alkali. PET fabric was treated with aqueous as well as methanolic solutions of sodium hydroxide in the presence of additives namely, a quaternary ammonium compound, cetyltrimethylammonium bromide (CTAB) and an ionic liquid, 1-butyl-3-methylimidazolium chloride ([BMIM]Cl). The process parameters were optimized for desired level of treatment and the effect evaluated in terms of reduction in fabric weight and SEM images of the samples. Weak methanolic NaOH showed greater effect than aqueous NaOH solution. Also, the addition of [BMIM]Cl enhanced the effect better than CTAB. Results of ANOVA analysis showed that temperature played very significant role and time was of less significance for treatment using [BMIM]Cl. Both the parameters were insignificant for the conventional and CTAB treatments. Thus, the use of novel eco-friendly additive [BMIM]Cl can cause conservation in terms of time and temperature in this commercially important process.