NOPR Collection:

Flexing behaviour of high strength coated fabrics

2021-01-05T08:41:13Z

Title: Flexing behaviour of high strength coated fabrics Authors: Bharathi, D; Alagirusamy, R; Joshi, M; Prasad, N Eswara; Das, B R Abstract: Flexing characteristics of three varieties of thermoplastic polyurethane (TPU) coated high strength fabrics (nylon 6,6, polyester and kevlar) have been evaluated by subjecting them to 5000 cycles in a De-Mattia flex tester. The flexing damage is assessed in terms of % loss of strength by evaluating the residual tensile strength of flexed fabrics. Statistical analysis has been carried out at 95% significance level for assessing the influence of flexing cycles and variation in thermoplastic polyurethane concentration on the residual strength of coated kevlar fabrics. Accordingly, the specific trend exhibited is established. The study shows that the coated kevlar fabric has suffered with maximum strength loss, while nylon and polyester show excellent flex damage resistance with negligible strength loss. Further, the sensitivity to damage of kevlar fabric has been studied by varying the number of flex cycles from 1000 to 5000 and the extent of damage that happened within the structure is thoroughly analyzed using field emission scanning electron microscope. Finally, the possible mean of improving strength retention (22%) of coated kevlar fabric subjected to repeated flexing by the application of a proprietary high viscosity polymer coating has been proposed. Page(s): 381-387

Effect of yarn count and loop length on needle penetration force and needle cut index in single jersey fabrics

2021-01-05T08:38:47Z

Title: Effect of yarn count and loop length on needle penetration force and needle cut index in single jersey fabrics Authors: Bansal, Payal; Sikka, Monica; Choudhary, AK Abstract: The present study embodies the sewability of single jersey knitted fabric based on needle penetration force and needle cut index. Four types of single jersey fabric, viz. 100% cotton, polyester/cotton, polyester/lycra, and cotton/lycra, are taken for investigation. The materials are prepared on circular knitting machine by varying the yarn count and loop length. The influence of various parameters, viz. type of fibre, yarn count and loop length, on needle penetration force and needle cut index have been analyzed. In addition, the influence of seam direction on the needle cut index is also studied. A 3^_level factorial design is employed to analyse the influence of there parameters. The statistical analysis shows that yarn count and loop length has a significant effect on needle penetration force and needle cut index. It has been observed that in all single jersey knitted fabrics, cotton-lycra and polyester-lycra half plated fabrics have higher value of needle penetration force than cotton and polyester/cotton. The test results also show that for both coarser yarn and finer yarn count, longer loop length gives a lower value of needle penetration force. The needle cut index decreases with increase in the yarn count and loop length. Also it is observed that, the needle cut index is more in wale direction as compared to that in course direction. It is also concluded that cotton fabric samples are more susceptible to needle damages as compared to their counterparts. Page(s): 388-394

Thermal comfort properties of modified yarn path in cotton fabrics

2021-01-05T08:36:39Z

Title: Thermal comfort properties of modified yarn path in cotton fabrics Authors: Rajwin, A Jebastin; Prakash, C Abstract: Effect of the modified yarn path in ring spinning on the thermal comfort behavior of the cotton woven fabric has been investigated. The modified ring yarn is produced by changing the path of the yarn in the ring spinning process. The finding shows that it has a clear impact on the fabric geometrical properties and thermal comfort properties when path of the yarn is changed in ring spinning as left and right diagonal path. It is also observed that the air permeability of the fabric decreases with the right diagonal yarn path and thermal resistance of the fabric increases with the right diagonal yarn path. The fabric woven from the left diagonal yarn path shows higher water vapour permeability. Page(s): 395-401

Extraction of natural dye from Mammea suriga and its application on silk and cotton fabrics

2021-01-05T08:34:55Z

Title: Extraction of natural dye from Mammea suriga and its application on silk and cotton fabrics Authors: Verenkar, N; Krishnan, S Abstract: In this study, raw silk and cotton fabrics have been dyed using the aqueous extract from Mammea suriga bark in the presence of chemical mordants. The variations in the colour are seen in the silk and cotton fabrics by using different mordants. The preliminary phytochemical tests reveal the presence of tannins in the bark extract of the plant, which is responsible for imparting brown colour shades to the silk and cotton fabrics. The results are found promising with good fastness property in all the three mordanting methods, i.e. pre-mordanting, simultaneous mordanting and post-mordanting. The SEM study shows no physical damage to the fibre dyed with M. suriga dye extract. Thus, this bark can be used as a cheaper source of raw material for the extraction of natural dye by dyers in dyeing industries. Page(s): 402-410