Spinning Process Variables Research Articles

Analyzing the effect of spinning process variables on blow room blended cotton melange yarn quality

PurposeThe use and importance of mélange yarn in apparel sector is increasing day by day. With the gradual increase in market share, achieving the desired quality level of mélange yarn remains a challenge for yarn manufacturing industry. The purpose of this paper is to investigate the effect of raw material (dyed fiber percentage in the mixing), important spinning process variable (yarn twist multiplier) and productivity (spindle rpm of ring frame) on properties of cotton mélange spun yarn.Design/methodology/approachBox and Behnken Design of experiment has been used to investigate the important yarn quality parameters like evenness, imperfection, hairiness, breaking strength and breaking elongation of blow room blended cotton mélange yarn. The quadratic regression model is used to derive the statistical inferences about sensitivity of the yarn quality parameters to the different process variables. The response surfaces are constructed for depicting the geometric representation of yarn quality parameters plotted as a function of process variables.FindingsThe study shows that shade depth and spindle speed have significant effects on the mélange yarn unevenness and imperfections. Mélange yarn strength and hairiness are significantly affected by shade depth and yarn twist multiplier (TM). Yarn elongation at break is only influenced by the spindle speed. A darker shade is responsible for higher yarn unevenness, imperfection, hairiness and lower yarn strength. A higher spindle speed is also liable for deterioration of yarn quality.Practical implicationsMany spinning industries are planning to convert their existing spindles from normal gray yarn production to mélange yarn manufacturing. The outcome of this study will lead to achieve better mélange yarn quality and productivity by the industry.Originality/valueResearch on mélange yarn is itself scant. This study is exclusively conducted to analyze the individual and interactive effect of various process parameters on the mélange yarn quality.

Analyzing the Effect of Spinning Process Variables on Draw Frame Blended Cotton Mélange Yarn Quality

An investigation has been made to study the effect of important spinning process variables namely shade depth, ring frame spindle speed and yarn twist multiplier (TM) on various yarn quality parameters like unevenness, strength, imperfection, elongation at break and hairiness index of draw frame blended cotton melange yarn. Three factors Box and Behnken design of experiment has been used to conduct the study. The quadratic regression model is used to device the statistical inferences about sensitivity of the yarn quality parameters to the different process variables. The response surfaces are constructed for depicting the geometric representation of yarn quality parameters plotted as a function of process variables. Analysis of the results show that yarn strength of draw frame blended cotton melange yarn is significantly affected by shade depth and TM. Yarn unevenness is affected by shade depth and ring frame spindle speed. Yarn imperfection level is mainly influenced by the shade depth and spindle speed. The shade depth and yarn TM have shown significant impact on yarn hairiness index.

High-performance ester-crosslinked hollow fiber membranes for natural gas separations

A significantly improved defect-free ester-crosslinkable hollow fiber membrane was developed through simultaneous optimization of the spinning solution and dry-jet/wet-quench spinning process variables. The resultant ester-crosslinked hollow fibers show extremely high separation productivity and efficacy with CO2 plasticization resistance under aggressive feed conditions. The CO2 permeance was improved from 50 GPU to 117 GPU with a CO2/CH4 selectivity of 37 in testing at 200psi with 50/50 CO2/CH4 feed, 35°C. Moreover, the crosslinked hollow fibers maintain a high CO2 permeance under highly aggressive feed pressures up to 800psi of 50/50 CO2/CH4 feed without CO2 plasticization. A lower operating temperature can improve the CO2/CH4 selectivity significantly without apparent loss of CO2 permeance. The mixed gas permeation with high CO2 feed pressure demonstrates that ester-crosslinked hollow fiber membranes provide a significant advance in the state of the art for CO2/CH4 separations.

Structure and properties development in poly(phenylene sulfide) fibers, part I: Effect of material and melt spinning process variables

AbstractThe detailed research study of manufacturing PPS fibers using melt spinning and further enhancement of tensile properties by drawing and annealing experiments, a study lacking as of today in open scientific literature, was the focus of this research. This article discusses the effect of polymer molecular weight (MW) and melt spinning process variables on the structure and properties development in melt spun fibers manufactured from proprietary Fortron® linear PPS resins. Structure‐properties relationship was studied using several characterization tools like tensile testing, differential scanning calorimetry, polarized light optical microscopy, and wide‐angle x‐ray scattering. Changes in dynamic mechanical behavior of as‐spun fibers manufactured from resins of varying MW and different melt spinning take‐up speeds were also studied. The study showed that by a combination of higher MW of the polymer and spinning at higher take‐up speeds, tensile properties of as‐spun PPS fibers can be improved. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011

Properties of high modulus PEEK yarns for aerospace applications

AbstractA study has been carried out on the influence of extrusion and drawing related process parameters with an object of obtaining high modulus poly ether ether ketone yarns that can be tailor made to meet critical requirements of aerospace applications. The influence of the interaction between rheological properties, spinning process variables, and drawing conditions has been given special attention to engineer a yarn that exhibit excellent structure property relationships. The wide angle X‐ray diffraction results suggest that drawing carried out above glass transition temperature (Tg) influences the structure that include unit cell parameters, density, and mechanical properties. The degree of orientation characterized in terms of sonic velocity measured as high as 3 km/s with sonic modulus of 105 gpd. With progressive increase in draw temperature, crystallinity was found to increase, and useful properties were observed at an optimum draw temperature of 200°C (may be region of maximum crystallization rate) primarily attributed to the maximum crystallization temperature and the heat setting effect. Thermal studies (TGA) indicate that these materials can be used in high temperature applications (up to 250°C) for long time exposure and 500°C for short term exposure. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009

Analysis of spinning process using the Taguchi method. Part IV: Effect of spinning process variables on tensile properties of ring, rotor and air-jet yarns

The yarn samples prepared for migration study were tested for tensile properties. Furthermore, the effect of drafts of the spinning machines on yarn strength and breaking elongation (%) was studied. The effect of spinning position, doff position and material conditioning during testing on yarn tensile properties were also accounted for. The ring yarn was seen to have the highest tensile properties, whereas air-jet yarns the lowest. The low elastic recovery of viscose fibres is the cause of weakest and least extensible air-jet yarns.

Analysis of spinning process using the Taguchi method. Part II: Effect of spinning process variables on fibre extent and fibre overlap in ring, rotor and air-jet yarns

The fibre orientation in 24s Ne ring, rotor and air-jet yarns has been studied using tracer fibre technique. The effect of drafts at different stages of spinning process on fibre orientation in different yarns has been analyzed using Taguchi Method and analysis of variance. The fibre orientation was studied in terms of fibre extent (FE) and two newly defined indices (FOIs), fibre-overlap index (FOI) and fibre-pair-overlap length (FPO). Ring yarn is seen to have the highest FE and FOIs and rotor yarn the least. A medium card draft (101 or 114) and a corresponding ring or speed frame draft give the highest FE. The effect of fibre parallelization in finisher sliver is retained in respect of FE and FOIs in rotor and air-jet yarns. The effect of fibre parallelization in rovings is manifested on FOI of ring yarns. A higher card draft and correspondingly lower air-jet draft give higher FE and FOIs.

Spinning process variables and polymer solution effects in the die-swell phenomenon during hollow fiber membranes formation

During hollow fiber spinning many variables are involved whose effects are still not completely clear. However, its understanding is of great interest because the control of these variables may originate membranes with the desired morphologies and physical properties. In this work, the phase inversion process induced by the immersion precipitation technique was applied to prepare hollow fibers membranes. It was verified that some of the variables involved, can promote a visco-elastic polymer solution expansion, called die-swell phenomenon, which is undesired since it may lead to low reproducibility of the permeation properties. The effects of the distance between spinneret and precipitation bath, the bore liquid composition, and the polymer solution composition were analyzed and discussed in order to avoid this phenomenon. According to the results, it was verified that the parameters investigated might promote a delay precipitation, which restrained the visco-elastic expansion.

Nanocrystalline exchange-enhanced hard magnetic alloys

The effects of microstructural refinement into the nanocrystalline range on the magnetic properties of iron-rare earth alloys are briefly reviewed and discussed. The influence of composition, including departures from the stoichiometric ratio and alloying additions, and of melt spinning process variables on the microstructure and properties are identified and the commercial prospects for nanophase bonded magnets considered.

Polyaramide hollow fibers for hydrogen/methane separation — spinning and properties

The Du Pont family of aromatic polyamides is intrinsically superior to other polymers currently commercially used for hydrogen/methane separation. These polyaramides can be easily spun into highly asymmetric hollow fiber membranes. Due to their high glass transition temperature, modulus and yield stress, as compared to other currently commercially-used polymers, the resulting polyaramide hollow fibers exhibit a high collapse pressure and can operate at high temperatures with good retention of permeation properties. For example, at Conoco's Ponca City Refinery, 11-inch diameter, 10-foot long commercial permeators have been in operation for longer than a year purifying a feed stream of 74% hydrogen to 97% hydrogen at a recovery of 76%. Each permeator is capable of processing approximately six million standard cubic feet per day. The number of solvents available for polyaramides is limited, but a proper spin dope formulation can be obtained by using appropriate organic and inorganic additives. Such a spin dope formulation, combined with appropriate control of the spinning process variables, provides sufficient flexibility to control membrane morphology to produce macrovoid-free fibers for high pressure applications with skin thickness of less than 1,000 Angstroms. The solubility characteristics of polyaramides for membrane preparation and the rheology of the spin-dopes will be discussed and the effect of spinning parameters on membrane permeation properties will be illustrated.

Effect of comonomer content and annealing on morphological changes in acrylic copolymers and fibers

AbstractA better understanding of internal microstructure is necessary to understand various properties of acrylic fibers, such as dyeability, mechanical properties, and comfort. In the present paper, the application of x‐ray methods for the investigation of fiber microstructural parameters, namely, crystallinity and crystallite size, is demonstrated. Effect of comonomer incorporation on acrylic copolymer microstructure is assessed in the present work. Influence of annealing aftertreatment on the changes in structure is investigated using the evidence presented by x‐ray and DSC studies. Introduction of small amounts of a comonomer (methyl acrylate, MA) results in diminishing crystallinity. Annealing of acrylic copolymers causes the onset of an intramolecular cyclization, as well as an increase in segmental mobility; both these factors lead to an increase in crystallinity and crystallite size. With increasing comonomer content, the exothermic peak in the thermogram is found to shift toward higher temperatures. Some evidence is presented that shows the effect of spinning process variables on acrylic fiber microstructure. The results and findings of the present work have been interpreted in terms of a two‐phase structure for acrylic fibers.