NOPR Collection:

Production and characterisation of microbial cellulosic fibre from Acetobacter xylinum

2014-03-11T18:07:53Z

Title: Production and characterisation of microbial cellulosic fibre from Acetobacter xylinum Authors: Gayathry, G; Gopalaswamy, G Abstract: Bacterial cellulose (BC) has been produced by the Gram negative bacterium Acetobacter xylinum at the air liquid interface of sugary rich medium. The BC has been produced from Hestrin Shramn (HS) medium using the efficient cellulose-producing culture isolated from sugarcane juice under static batch fermentation condition. Results show that A. xylinum (sju-1) produces 11g/L BC after 14 days of fermentation period. The water holding capacity of bacterial cellulose is found to be 84.4 %. The tensile strength, Young’s modulus, viscosity and degree of polymerisation of bacterial cellulosic fibre are found to be 120 MPa, 4.9 GPa, 127.4 cP and 2074 respectively. The FTIR results reveal the presence of hydroxyl and CH₂ stretching behaviour at the absorption wavelength of 3229 cm^-1 and 2911cm^-¹.The banding patterns of bacterial cellulose closely resemble the structure of pure celluloses. A. xylinum (sju-1) isolate produces bacterial cellulose of type Iα in quantities of commercial interest. The findings of the research reveal that bacterial cellulose can be used in making absorbent pads and nonwoven textiles. Page(s): 93-96

Influence of polyester fibre shape and size on the hairiness and some mechanical properties of yarns

2014-03-12T18:06:37Z

Title: Influence of polyester fibre shape and size on the hairiness and some mechanical properties of yarns Authors: Varshney, R K; Kothari, V K; Dhamija, S Abstract: Polyester fibres of different linear densities and cross-sectional shapes have been spun on ring frame at different twist levels. These yarn samples are subjected to the deformation both in tensile and bending mode to investigate the yarn behavior as a consequence of change in cross-sectional shape and fineness of polyester fibres. Young’s modulus as well as bending rigidity of yarns increases with the increase in fibre linear density. These properties of yarns made of trilobal and tetrakelion fibres are higher in magnitude than those of their corresponding circular fibres, whereas the behaviour is opposite if scalloped oval fibre is dealt. As far as yarn hairiness is concerned, the higher the polyester fibre denier, the higher will be the hairiness count. Yarns made of scalloped oval fibres exhibit maximum numbers of hairs followed by tetrakelion and the circular fibres yarns respectively. Similarly the yarns of trilobal fibres are more hairy than their counterparts made of circular fibres. Page(s): 24-32

Effect of xylanase enzyme on mechanical properties of fibres extracted from undried and dried corn husks

2014-03-11T18:07:07Z

Title: Effect of xylanase enzyme on mechanical properties of fibres extracted from undried and dried corn husks Authors: Yılmaz, Nazire Deniz; Çalışkan, Ebru; Yılmaz, Kenan Abstract: Fibres have been extracted from corn husks in undried and dried forms by an alkalization treatment followed by enzymatic process at different concentrations of xylanase enzyme. The effects of drying process and xylanase enzyme concentration on the mechanical and textile properties of corn husk fibres have been investigated. The linear density of extracted fibres decreases with the increase in enzyme concentration and drying. Increasing enzyme concentration increases the breaking tenacity and initial modulus up to a point and then decreases them with any further increase in concentration. Fibres obtained from dried husks show dull colour as compared to those obtained from undried husks. No negative effect of drying process is observed on the performance of corn husk fibres. The highest tensile performance and fineness values are obtained from fibres of dried husks, treated with 0.4% Pentopan® mono BG enzyme, with a breaking tenacity of 9.44 cN/tex, initial modulus value of 282 cN/tex, and a fineness of 21.6 tex. Page(s): 60-64

Physiological responses of different types clothing in cold weather condition – A wear trial study

2014-03-11T18:06:47Z

Title: Physiological responses of different types clothing in cold weather condition – A wear trial study Authors: Shabaridharan; Das, A; Gersak, J Abstract: The subjective and objective evaluation ofdifferent types of jackets meant for cold weather condition has been done. Fourjackets have been produced with different types of insulative layers. Knitted polyesterfabric and polyester polymer coated fabric have been used as inner and outerlayers respectively for all the four jackets. Polyester needle-punched nonwoven fabrics produced from finer fibre (1.5 den) and hollow fibres (6 and15 denier), and air bonded nonwoven polyester fabrics are used as middle layer.The wear trial study has been performed in the environmental chamber at threedifferent temperatures, viz. 10°C, 0°C and -10 °C for 80 min duration accordingto EN ISO 10551:2001 and the jackets are evaluated by wearer for the thermalcomfort at start, middle and end of the test. The clothing layers used in thejackets are objectively evaluated for thermal and evaporative resistance bysweating guarded hot plate according to ASTM F 1868-Part C. In wear trailstudy, the body mass of the wearer with and without clothing, weight of jacketsand other clothing is measured before and after each test along with the microclimatetemperature and relative humidity at eight different parts of the bodyaccording to EN ISO 9886:2004. The Spearman’s correlation coefficient, calculatedbetween subjective and objective evaluation, is found to be high at lowerambient temperature. The jackets consisting of hollow fibres are found toperform better in cold weather conditions. The jacket showing maximum thermalinsulation in objective evaluation is found failed to give comfortable feel tothe wearer in wear trials. Page(s): 33-42