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Effect of Twist on Flexural Rigidity and Elastic Recovery of Acrylic-Viscose Rotor-spun Yarns

Tue, 01 Dec 1987 00:00:00 GMT

Title: Effect of Twist on Flexural Rigidity and Elastic Recovery of Acrylic-Viscose Rotor-spun Yarns Authors: Kaushik, R C D; Salhotra, K R; Tyagi, G K Abstract: All-viscose fibre yarns showed higher flexural rigidity and lower elastic recovery. An increase in twist led to a significant increase in yarn flexural rigidity. The rigidity of the fibres being blended and their position in the yarn also affected the flexural rigidity of the blended yarn. Page(s): 220-221

Role of Bacterial Growth and Their Extracellular Enzymes in Softening of Hard Root-cuttings of Jute

Tue, 01 Dec 1987 00:00:00 GMT

Title: Role of Bacterial Growth and Their Extracellular Enzymes in Softening of Hard Root-cuttings of Jute Authors: Majumdar, S; Ghosh, B S; Kundu, A B Abstract: The types of bacteria and their extracellular catabolic enzyme activity in a mixed bacterial culture, developed to bring about appreciable softening of hard root-cuttings of jute, were characterized. The bacterial population showed a typical diauxic growth and started secreting enzymes after 48 h of growth, which coincided with the beginning of softening process. D-glucose, a catabolite repressor, inhibited softening as well as the synthesis of bacterial extracellular proteins by 97% when added within two and a half days of incubation, later addition being ineffective. Bacterial cell-free culture supernatant, having catabolic enzyme activities, such as those of pectin transeliminase, polygalacturonase, pectin methylesterase, (jute) hemicellulase and CMCase, liberated sugars from sterile root-cuttings but was unable to bring about softening to the extent comparable to in-situ bacterial growth. However, when the supernatant was added along with the ruptured bacterial cell solids, the degree of softening was increased by 17%. A similar observation of partial softening was observed when the sterile cuttings were treated with a combination of proprietary fungal enzymes. Page(s): 213-219

Stress-Strain Properties of Merino, Chokla and Rambouillet × Chokla Dyed Yarns

Tue, 01 Dec 1987 00:00:00 GMT

Title: Stress-Strain Properties of Merino, Chokla and Rambouillet × Chokla Dyed Yarns Authors: Parthasarathy, S; Chopra, S K; Bapna, D L Abstract: The yarns spun from Merino, Chokla and Rambouillet × Chokla wool fibres were dyed at pH 2.5, 4.5 and 6.5 for 1 h and 3 h at 100^ᵒC; they were also boiled in water for the same periods. The treated yarns and the control were tested for tensile properties and the different parameters were analyzed statistically. Dyeing modified the tensile properties. The behaviour of the yarns differed in the different treatments. In general, dyeing improved the stress at 2% extension and it was highest in pH 6.5 and boiling-water treatments. The hookean and yield slopes were lowered by the treatments. However, after 3 h treatment the yield slope increased owing to treatment. The breaking stress and extension were also significantly influenced by the treatment and genetic groups. The interaction was significant in most of the cases. Page(s): 207-212

Effect of Twist, Core-Sheath Parameters and Post-dyeing Treatment on Characteristics of Nylon-Viscose Core-spun Yarns

Tue, 01 Dec 1987 00:00:00 GMT

Title: Effect of Twist, Core-Sheath Parameters and Post-dyeing Treatment on Characteristics of Nylon-Viscose Core-spun Yarns Authors: Tyagi, G K; Singh, H D Abstract: The effect of sheath fibre denier, twist and dyeing treatment on the characteristics of core-spun yarns having a mono and multi-filament nylon core was studied. Yarn strength and breaking extension decreased with increase in core filament denier, but were higher for yarns spun with finer denier sheath fibres. Yarns dyed with a direct dye showed a greater loss in strength and extension than the yarns dyed with a reactive dye. Core-spun yarns with multifilament core exhibited a smaller diameter, which increased after dyeing. Page(s): 201-206