Formation and characterisation of cellulose II/partially deacetylated cellulose acetate bicomponent fibres and associated properties

The work presented herein represents the fabrication of cellulose II/cellulose acetate wet-spun bicomponent fibre that were successfully created through a time-manipulative deacetylation process using ethanolic NaOH solution. Infrared spectroscopy was used to observe the degree of deacetylation by comparing the absorption intensities of C=O and C−O stretches. Results showed that the CA fibres periphery was deacetylated at a higher rate than the core layer in which the deacetylation rate observed with ATR-FTIR (−0.634 min−1) was twice as rapid as the deacetylation rate observed with FTIR (−0.315 min−1). The objective kinetic analysis revealed a high degree of correlation (R2 > 0.99), expressed by ‘acetyl factor’ and these findings were aligned with subjective evaluation using confocal microscopy images of fibre cross-sections. It was observed that changes in fibre morphology occurred with treatment time and progressive alkaline treatment of cellulose acetate to cellulose II giving a well-defined sheath/ core bicomponent fibre structure, evidenced by a high correlation value of R2 = 0.8617 between both objective and subjective evaluation results. Additionally, this research study explored the crystallinity structure of the bicomponent fibre and its effect on mechanical properties, particularly moisture absorption and tensile strength characteristics. Alkaline treatment considerably enhanced the fibre’s crystallinity as well as moisture absorption capacity, while maintaining satisfactory tensile strength characteristics. Further, bicomponent fibres are discussed, which, based on the research findings, shows a potential for smart textile applications requiring a controlled-release system that takes account of differential moisture properties.