Coconut fibres were subjected to chemical treatment to obtain softer and finer fibres, suitable to blend with other finer fibre like jute. The chemical softening recipe was optimized using Box-Behnken design of experiments as 40 % Na2S, 10 % NaOH and 6 % Na2CO3, which notably reduced the fineness (33 %) and flexural rigidity (74 %) and improved tensile property of coconut fibre. Effect of softening of coconut fibre on its process performance was studied in high speed mechanized spinning system at different blend ratios with jute. Blending with jute assists in spinning of coconut fibre to produce yarn of 520 tex at production rate of 5-6 kg/h, as compared to 15 kg/day for hand spun 5300 tex raw coconut fibre yarn in manual system. Analysis of blended yarn structure in terms of packing density, radial distribution of fiber components (SEM) and mass irregularity were investigated. SEM shows yarns made from softened coconut fibre -jute blends are more compact than raw coconut fibre -jute blend yarns. Coconut fibres were preferentially migrated to core of the yarn. Major yarn properties viz., tensile strength, and flexural rigidity of raw and chemically softened blended yarns were compared against their finest possible 100 % coconut fibre yarn properties. Yarn made up to 50:50 chemically softened coconut fibre-jute blend showed much better spinning performance, and having superior property in terms of reduced diameter, higher compactness, strength, initial modulus and less flexural rigidity than 100 % raw, 100 % chemically softened coconut fibre rope, and raw coconut fibre-jute blend yarns.

Effect of chemical softening of coconut fibres on structure and properties of its blended yarn with jute

Jute and jute-modacrylic yarns of various blend ratios have been prepared and treated with different concentrations of NaOH (5% -22% w/w). It is observed that this treatment results in axial shrinkage and weight loss of the yarns. The axial shrinkage increases with the increase in NaOH concentration up to 18% whereas the weight loss increases with the increase in NaOH conc. up to 22%. Even though the tenacity and modulus of yarns decrease substantially on alkali treatment, the work of rupture increases after treatment which is mainly due to the increase in breaking elongation. Statistical analysis shows that the modulus of different strain levels and tenacity values are positively and significantly correlated with the packing fraction values of the yarns. Blending of modacrylic fibre with jute does not show any appreciable improvement in bulk property of yarn. However, the whiteness index and mean gray value of alkali-treated blended yarns confirm the improvement in appearance of the yarns due to the preferential migration of modacrylic fibres on the surface of the yarn.

/pdf/studies-on-the-properties-of-alkali-treated-jute-modacrylic-48nsfp07ce.pdf

Gautam Basu

Papers

Studies on the properties of alkali-treated jute-modacrylic flyer-spun yarns