Peracetic acid bleaching of banana fibre: Process optimisation

Abstract

AbstractBanana is an important commercially available natural fibre, suitable for making coarse yarns. It has also potential for making fine home and apparel textiles after requisite chemical intervention or blending with other fine fibres. For making such products, chemical processing, namely bleaching, coloration and finishing, play an important role. Bleaching of fibre is generally carried out in highly alkaline condition and at high temperature of 85°C using hydrogen peroxide to achieve whiteness index of > 70 with about 25% loss in tensile strength. To achieve a similar whiteness index, while addressing strength loss, a fibre friendly low‐temperature low‐alkali based peracetic acid (PAA) bleaching of banana fibre has been proposed in the present article. Important bleaching process parameters, namely PAA concentration (10–30 g/L), time (60–180 min) and temperature (60–80°C), have been varied for optimisation of the bleaching process. Banana fibre bleaching using PAA concentration of 20 g/L at 70°C for 2 h can produce fibre with whiteness index of > 70, which is suitable for subsequent coloration. The PAA bleached banana fibre can retain 84% of its bundle strength and 95.6% of its weight. Physical (strength, fineness), chemical (attenuated total reflectance Fourier‐transform infrared [ATR‐FTIR], energy dispersive X‐ray spectroscopy [EDX]), optical (colour) and morphological (scanning electron microscopy [SEM]) properties of banana fibres before and after bleaching were evaluated to study the efficacy of the process.