NOPR Collection:

Influence of yarn structure, sizing ingredients and type of sizing on properties and performance of sized yarns: Part II-A comparative study of sized yarn performance for ring- and rotor-spun cotton yarns

Sat, 01 Jun 2002 00:00:00 GMT

Title: Influence of yarn structure, sizing ingredients and type of sizing on properties and performance of sized yarns: Part II-A comparative study of sized yarn performance for ring- and rotor-spun cotton yarns Authors: Sengupta, A K; Pratihar, P; Kimothi, P D; Vernekar, S; Sayeed, M M Alamgir Abstract: A comparative study on influence of structural differences of ring- and rotor-spun cotton yarns on the process of sizing and the performance of sized yarns against abrasion has been carried out using the 6s and 16s ring and rotor yarns sized with cold and hot brand PVA at different concentrations (9%, 7% and 5%) and drying rates (70°C and 140°C). It is observed that, in general, the abrasion resistance of rotor yarns is better than that of ring yarns. The rotor yarns give better abrasion resistance at 140°C because the higher temperature reduces size migration from inside to surface of the yarn, thereby ensuring more uniform deposition of size along the cross-section of the yarn. A better size distribution reinforces the open structure of rotor yarns and improves cohesion. Page(s): 142-148

Investigations into homogeneity of coir fibres

Sat, 01 Jun 2002 00:00:00 GMT

Title: Investigations into homogeneity of coir fibres Authors: Banerjee, P K; Chattopadhyay, R; Guha, A Abstract: Experimental investigations on certain dimensional and mechanical properties of retted coir fibres reveal a very broad spectrum. The fibres measuring less than 150 mm in length appear very similar in terms of all the properties investigated and hence it is suggested that these fibres should be targeted for segregation and softening in order to design new processes and products-among others the very promising coir-based geotextiles-for coir industry. Page(s): 111-116

Solvent-induced modifications in poly (ethylene terephthalate) structure, properties and dyeability

Sat, 01 Jun 2002 00:00:00 GMT

Title: Solvent-induced modifications in poly (ethylene terephthalate) structure, properties and dyeability Authors: Chidambaram, D; Venkatraj, R; Manisankar, P Abstract: Poly (ethylene terephthalate) fibre (PET) is the commonly used man-made fibre for majority of end-use applications. In the past few decades, the significant technological developments have taken place pertaining to the production processes of PET. Regarding the dyeing of PET, there is a constant upsurge in research and development activities to modify the structure of PET with a view to develop energy efficient processes. Among the notable developments, the low molecular weight solvent treatment results in physical modifications of polymer and fibre like PET, which include structural modifications and changes in properties. Owing to the structural modifications of PET fibre, the dyeability also improves. Some of the pioneering works on solvent-induced modifications of PET structure, properties and dyeability during the past few years have been reviewed. Page(s): 199-210

Thermal studies on cellulose cyclohexenephosphonate in air

Sat, 01 Jun 2002 00:00:00 GMT

Title: Thermal studies on cellulose cyclohexenephosphonate in air Authors: Dahiya, J B; Sushila Abstract: The flame retardancy of the cellulose cyclohexenephosphonate (CCHP) has been investigated by the kinetics of thermal degradation using differential thermal analysis (DTA) and thermogravimetry (TG) from ambient temperature to 700°C in dynamic air. Various parameters such as energy, entropy and free energy of activation have been calculated using the Broido method and transition state theory. For the decomposition stage of thermal degradation, the activation energy of CCHP has been found to be 133.83 kJ mol^-¹ which is lower than that of cellulose (187.0 kJ mol^-1). Higher char yield of CCHP as compared to cellulose leads to the conclusion that CCHP is a good flame retardant. The IR spectra of the chars of modified cellulose indicate formation of compounds containing C=O, C=C and P=O groups. The mechanism of thermal degradation of CCHP has been proposed. Page(s): 189-193