bluuebunny/crossref_metadata_2025 huggingface dataset:
A Computational Fluid Dynamics Modeling and Experimental Study of the Mixing Process for the Dispersion of the Synthetic Fibers in Wet-Lay Forming
Authors: Ramasubramanian Melur K. , Shiffler Donald A. , Jayachandran Amit
Published: November 2018

In this paper, we present results from a computational fluid dynamics (CFD) model for the mixing process used to disperse synthetic fibers in wet-lay process. We used CFD software, FLUENT, together with the MIXSIM user interface to accurately model the impeller geometry. A multiple reference frame (MRF) model and standard k-e turbulence model were used to model the problem. After obtaining a converged solution for the mixing tank with water, a discrete phase model was constructed by injecting spherical particles into the flow. A mixing tank with baffles and a centrally located impeller was used in experiments. PET fibers (1.5 denier, 6.35, 12.7, and 38.7 mm) at a concentration of 0.01% were mixed in water for the study. In regions behind the baffles, where the model predicted higher concentration of particles, experimental results showed a 34% higher concentration relative to the region in the high turbulence zone near the center. Instantaneous sheets were formed by rapidly dipping and removing a flat wire mesh strainer into the tank at two different locations to assess the state of dispersion in the tank. The sheets were transferred onto a blotting paper and examined under a microscope to count defects. Results show that the number of rope defects was 43% higher in sheets drawn from the region behind the baffles than in the sheets drawn from regions near the center of the tank. Changing baffles from a rectangular to a triangular cross section decreased the number of rope defects, but increased the number of log defects in the sample sheets at the same location. The CFD model can be used to optimize mixing tank design for wet lay fiber dispersion. The model provides further insight into the mixing process by predicting the effect of changes in design parameters on dispersion quality.
Two-Scale Modeling Approach to Predict Permeability of Fibrous Media
Authors: Jaganathan Sudhakar , Tafreshi Hooman V. , Pourdeyhimi Behnam
Published: November 2018

We previously demonstrated how one can develop a 3–D geometry to model the fibrous microstructure of a nonwoven fiberweb and use it to simulate its permeability at fiber level [1–6]. Developing 3–D models of most nonwoven fabrics (bonded fiberwebs), however, is cumbersome, as in the case of hydroentangled fabrics, for instance. In such cases, microscopic techniques are often used to generate 3–D images of the media's microstructures. Nevertheless, whether the microstructure is modeled or obtained from 3–D imaging, extensive computational resources are required to use them in fluid flow simulations [7]. To circumvent this problem, a two-scale modeling approach is proposed here that allows us to simulate the entire thickness of a commercial fabric/filter on a personal computer. In particular, the microscale permeability of a hydroentangled nonwoven is computed using 3–D reconstructed microstructures obtained from Digital Volumetric Imaging (DVI). The resulting microstructural permeability tensors are then used in a macroscale porous model to simulate the flow through the material's thickness and the calculation of its overall permeability.
Adjustment of Cotton Fiber Length by the Statistical Normal Distribution: Application to Binary Blends
Authors: Azzouz Béchir , Ben Hassen Mohamed , Sakli Faouzi
Published: November 2018

In this study the normality of the cotton fiber length number distribution and weight distribution are tested by using the Chi-2 statistic test. Good correlations between the cotton fiber length distribution by weight and the normal distribution with the same mean and standard deviation are obtained. This test further shows that length distribution by numbers cannot be characterized by normal law. Then, the staple diagram and the fibrogram by weight are mathematically generated from a normal fiber length distribution. After that, mathematical models relating the most common length parameters to the mean length and the coefficient of variation are established by solving the staple diagram and the fibrogram equations. Finally, the length parameters of binary blends are studied and their variations in terms of the components of the blend are shown. These variations are nonlinear for most of the blend length parameters in contrast to other studies and models usually used by the spinners that suppose that the blend characteristics and particularly length parameters are linear to the components ratios.
Capillary Rise in Macro and Micro Pores of Jersey Knitting Structure
Authors: Benltoufa Sofien , Fayala Faten , BenNasrallah Sassi
Published: November 2018

Wicking in textile materials is a very complicated, multi-faceted phenomena. This paper investigated capillary rise in a jersey knitting structure. A mathematical model was developed based on the industrial construction parameters and the capillary mechanism. The capillary is studied in two pore's scales: macro and micro. In order to validate our model, a series of experiments was conducted on cotton jersey knitting varying the construction parameters. The results showed reasonably good correlation between experimental data and the theoretical prediction for the wicking phenomenon in different pore's scales. Further refining of this model will be the subject of future research.
Heat Aged Tensile Strength Retention of Poly (p-phenylene terephthalamide) Sewing Thread
Authors: Hall Walter R. , Knoff Warren F.
Published: November 2018

The strength retention after exposure to elevated temperature in air of continuous filament and staple spun PPTA sewing thread and the precursor yarns was determined. For both types, the process of converting the greige yarn to thread reduced the amount of strength retained after thermal exposure. The continuous filament products retained more strength than the staple products. The data was fitted to a kinetic rate model in which two strength loss processes occurred. The first process occurred within about the first 5 minutes of thermal exposure and is hypothesized to be hydrolytic degradation. The estimated secondary degradation process activation energy suggests this to be thermo-oxidative degradation. Optical microscopy of filaments indicates a higher level of kink banding and other damage in continuous filament versus staple products and in finished thread versus the precursor yarns. The kink bands and damage are believed to be caused by the staple manufacturing process and the downstream processing of precursor yarn to finished sewing thread. The kink bands and damage are hypothesized to be responsible for the differences in strength retention.
Preparation and Characterization of Electrospun Fibers of Poly(methyl methacrylate) - Single Walled Carbon Nanotube Nanocomposites
Authors: Sundaray Bibekananda , Babu V. Jagadeesh , Subramanian V. , Natarajan T.S.
Published: November 2018

Electrospinning is a versatile method of preparing polymer nanocmposite fibers. Electrospun nanocomposite fibers of poly(methyl methacrylate) and single walled carbon nanotubes were prepared. The fibers were characterized by SEM, TEM, TGA and Raman spectroscopy. These fibers show dramatic improvement in the electrical conductivity compared to the polymer. The temperature dependent electrical resistance measurements show a one dimensional variable range hopping model (1–D VRH) type of conduction mechanism operating in these types of systems.
Determination of Radiative Thermal Conductivity in Needlepunched Nonwovens
Authors: Vallabh Rahul , Banks-Lee Pamela , Mohammadi Massoud
Published: November 2018

Radiation heat transfer is found to be the dominant mode of heat transfer at temperatures higher than 400–500K [11]. Convection heat transfer being negligible in nonwovens, effective thermal conductivity is given by the sum of its conduction and radiation components. In this research two methods were identified to determine radiative thermal conductivity of needlepunched samples made from Nomex fibers. The first method involved the determination of radiative thermal conductivity using effective (total) thermal conductivity determined using a Guarded Hot Plate (GHP) instrument. In the second method radiative thermal conductivity was estimated using the extinction coefficient of samples. The extinction coefficient was determined by using direct transmission measurements made using a Fourier Transform InfraRed (FTIR) spectrometer. Results confirmed that radiation was the dominant mode of heat transfer at temperatures higher than 535 K. The conduction component of effective thermal conductivity did not change much in the range of densities tested. Empirical models for predicting the temperature difference across thickness of the fabric and the radiative thermal conductivity with R-square values of 0.94 and 0.88 respectively showed that fabric density, fabric thickness, fiber fineness, fiber length, mean pore size and applied temperature were found to have significant effect on the effective thermal conductivity and its radiation component. Though a high correlation between the results of Method 1 (Guarded Hot Plate) and Method 2 (FTIR) was not seen, the absorbance measurements made using the FTIR spectrometer were found to have significant effect on the radiative thermal conductivity.
Collection Efficiency for Filters with Staggered Parallel Y and Triple Y Fibers: A Numerical Study
Authors: Zhu Huaning , Hinestroza Juan P.
Published: November 2018

A numerical study is performed to determine the collection efficiency of filters composed of staggered parallel Y and triple Y fibers. By employing the Lattice Boltzmann method, the Navier–Stokes equations are solved for flow fields in a two-dimensional domain with periodic boundary conditions. Trajectories of particles with different diameters arranging from 0.02 μm to 5 μm are then computed by solving the particle motion equation hence obtaining the collection efficiency of single Y and triple Y fibers. The effects of fiber orientation, Brownian motion, particulate size and Reynolds number on the collection efficiency of these two types of fibers are also evaluated numerically.

Y and triple Y fibers have low packing density and relatively large area to volume ratio, and the latter property helps enhance the Brownian diffusion collection mechanism for smaller particles. The large void zone of these fibers can accommodate more particles, which improves the particle loading capacity. It is also found out that the flow field and collection efficiency of triple Y fiber is less susceptible to different fiber orientations due to its geometric symmetry. The numerical results obtained in this work provide helpful information in designing high efficiency filters.
Simulation of Multifilament Semicrystalline Polymer Fiber Melt-Spinning
Authors: Jeon Young-Pyo , Cox Christopher L.
Published: November 2018

The goal of this effort is to provide an accurate simulation of multifilament fiber melt spinning, applicable for a wide range of material and process conditions. For ease of use, the model should run on a standard laptop or desktop computer in reasonable time (one hour or less). Most melt spinning models simulate the formation of a single filament, with little or no attention given to multifilament effects. Available multifilament simulations are primarily limited to Newtonian constitutive models for the polymer flow. We present a multifilament simulation based on the flow-enhanced crystallization approach of Shrikhande et al. [J. Appl. Polym. Sci., 100, 2006, 3240–3254] combined with a variant on the multifilament quench model of Zhang, et al. [J. Macromol. Sci. Phys., 47, 2007, 793–806]. We demonstrate the versatility of this model by applying it to isotactic polypropylene and polyethylene terephthalate, under a variety of process conditions.
The Importance of Collagen Fibers in Vertebrate Biology
Authors: Silver Frederick H.
Published: November 2018

Collagen fibers form the basic structural components of extracellular matrix (ECM) of vertebrates that serve to: (1) store elastic energy during muscular deformation, (2) transmit stored energy into joint movement, and (3) transfer excess energy from the joint back to the attached muscles for dissipation. They also act as mechanotransducers by transferring stress borne by the musculoskeleton to the attached cells in order to either up - or down - regulate tissue metabolism as a result of changes in mechanical loading. Finally, they prevent premature mechanical failure of tissues by limiting deformation of most ECMs and organs.
Electrospun Polydioxanone, Elastin, and Collagen Vascular Scaffolds: Uniaxial Cyclic Distension
Authors: McClure Michael J. , Sell Scott A. , Simpson David G. , Bowlin Gary L.
Published: November 2018

The development of vascular grafts requires the matching of material and viscoelastic properties to those of native artery. The hypothesis of this study was to subject electrospun tissue engineering scaffolds composed of polydioxanone, elastin, and collagen to cyclic loading in order to quantify the hysteretic properties, uniaxial tensile mechanical properties of conditioned scaffolds, and stress relaxation properties over a period of 400 cycles when compared to ePTFE, one of the most popular vascular prosthetic materials, and decellularized pig artery. In the electrospun graft, polydioxanone would provide a mechanical backbone, providing tensile support and preventing vessel rupture; while the elastin would provide elasticity and collagen would provide bioactivity (promote regeneration in vitro/in situ).
Copper Alginate-Cotton Cellulose (CACC) Fibers with Excellent Antibacterial Properties
Authors: Grace Mary , Chand Navin , Bajpai Sunil Kumar
Published: November 2018

The present work describes synthesis of copper alginate-cotton cellulose (CACC) composite fibers and detailed investigation of antimicrobial action against the model bacteria E.coli. The CACC fibers were prepared by immersing cotton fibers in aqueous solution of sodium alginate, followed by ionic crosslinking of alginate chains within the cotton cellulose fibers with Cu(II) ions to yield CACC composite fibers. The resulting CACC fibers were investigated for their biocidal action against E.coli, by using zone inhibition and colonies counting method. Finally, CACC fibers were reduced with sodium borohydride to yield copper nanoparticles-loaded composite fibers and investigated for biocidal action. It was found that CACC fibers possessed both, the fair mechanical strength and antibacterial action. The extent of biocidal action was found to depend upon the amount of Cu(II) loaded and concentration of alginate into cotton- cellulose fibers. The fibers showed higher Cu(II) release in physiological fluid as compared to distilled water. Copper alginate-cotton cellulose (CACC) fibers show fair mechanical strength and release copper ions in the presence of physiological fluid and protein solution. These fibers have great potential to be used as dressing materials.
Influence of Spinning Parameters and Recovered Fibers from Cotton Waste on the Uniformity and Hairiness of Rotor Spun Yarn
Authors: Mohamed Taher Halimi , Bechir Azzouz , Mohamed Ben Hassen , Faouzi Sakli
Published: November 2018

Improving raw material exploitation has become the most important challenge facing scientific and industrial community. In this paper, we have studied the effect of percentage of fibres recovered from cotton wastes and different spinning parameters on the hairiness, the uniformity and the level of irregularity of the rotor yarn. Results indicate that yarn count, rotor parameters (diameter and form) and rotor speed have an effect as significant as waste proportion. With a good choice of spinning parameters, an introduction of 25% on waste in the first passage in the drawing frame does not alter the uniformity and the appearance of rotor yarn.
Relationship of Fiber Properties to Vortex Yarn Quality via Partial Least Squares
Authors: Price Calvin , Senter Herman , Foulk Jonn , Gamble Gary , Meredith William
Published: November 2018

The Cotton Quality Research Station (CQRS) of the USDA-ARS, recently completed a comprehensive study of the relationship of cotton fiber properties to the quality of spun yarn. The five year study, began in 2001, utilized commercial variety cotton grown, harvested and ginned in each of three major growing regions in the US (Georgia, Mississippi, and Texas). CQRS made extensive measurements of the raw cotton properties (both physical and chemical) of 154 lots of blended cotton. These lots were then spun into yarn in the CQRS laboratory by vortex spinning with several characteristics of the yarn and spinning efficiency measured for each lot. This study examines the use of a multivariate statistical method, partial least squares (PLS), to relate fiber properties to spun yarn quality for vortex spinning. Two different sets of predictors were used to forecast yarn quality response variables: one set being only HVI” variables, and the second set consisting of both HVI” and AFIS” variables. The quality of predictions was not found to significantly change with the addition of AFIS” variables.
Tensile Behaviour of Spun Yarns under Static State
Authors: Das B. R.
Published: November 2018

The tensile properties of spun yarn are accepted as one of the most important parameters for assessment of yarn quality. The tensile properties decide the performance of post spinning operations; warping, weaving and knitting and the properties of the final textile structure; hence its accurate technical evaluation carries much importance in industrial applications. There is no doubt that all the studies related to tensile behaviour of spun yarns are invaluable both in theory and practice. In this article, a critical review of the theoretical and practical aspect of static tensile behaviour of staple yarns has been discussed.
Cellulose Acetate Fibers with Fluorescing Nanoparticles for Anti-counterfeiting and pH-sensing Applications
Authors: Hendrick Erin , Frey Margaret , Herz Erik , Wiesner Ulrich
Published: November 2018

Fluorescent silica nanoparticles, Cornell dots (C dots), were incorporated into electrospun cellulose acetate (CA) fibers. Two types of C dots were used in this study. The first type was comprised of a fluorescent dye-containing silica core surrounded by a silica shell. These nanoparticles fluoresce at 572 nm when exposed to 541 nm light. Increasing C dot loading in the spinning dope above 10% w/w did not result in an increase in C dot content within the final fibers. Scanning electron microscopy indicated that the nanoparticle incorporation had very little effect on the fiber morphology. The mechanical properties of the electrospun fabrics were not negatively affected by C dot addition, even though final loading constituted nearly one-third of the weight of the fibers. A second type of C dots, with both a fluorescent core and a pH-sensitive shell, were also incorporated in CA fibers. These C dots fluoresce at both 572 nm as described above, and at 518 nm, when exposed to 488 nm light. Fluorescence intensity at 541 nm increased with increasing pH. For both nanoparticle-incorporated fabrics, the resulting fibers are white under ambient lighting, and fluoresce at their given wavelengths of light.
Lab-Scale Fiber Spinning Experimental Design Cost Comparison
Authors: Moreland Jeffrey C. , Sharp Julia L. , Brown Philip J.
Published: November 2018

Many statistical experimental designs are too costly or require too much raw material to be feasible for lab-scale fiber spinning experiments. In this study a four-factor response surface design is presented to study the fiber spinning process in detail at the lab scale. The time, cost, and amount of raw material required to execute the proposed design are compared to the typical completely randomized 24 factorial design used in fiber spinning experiments and also to a standard four-factor response surface design. Sample fiber data as well as analysis from a typical statistical software package is provided to further demonstrate the differences between each design. By designating some treatment factors in the design as hard-to-change, split-plotting is used to reduce the time, cost, and amount of raw material required to complete the experiment. The proposed split-plot design is faster and less expensive than a typical factorial design and has the advantage of fitting a more complex second-order model to the system. When compared to a standard response surface design, the proposed split-plot design provides the same second-order modeling capabilities but reduces the cost of the experiment by 53%, the total time by 36%, and the amount of polymer required by 24%. Thus, a split-plot response surface design based on hard-to-change factors is recommended in lab-scale spinning.
Physical Characteristics of Titania Nanofibers Synthesized by Sol-Gel and Electrospinning Techniques
Authors: Park Soo-Jin , Kang Yong C. , Park Ju Y. , Evans Ed A. , Ramsier Rex D. , Chase George G.
Published: November 2018

Titania nanofibers were successfully synthesized by sol-gel coating of electrospun polymer nanofibers followed by calcining to form either the pure anatase or rutile phases. Characterization of these materials was carried out using scanning electron microscopy (SEM), transmission electron microscopy (TEM), diffuse reflectance Fourier transform infrared spectroscopy (DRIFTS), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and UV-vis spectroscopy techniques. The average diameter of these ceramic nanofibers was observed to be around 200 nm for both the rutile and anatase forms. The valence band structure and optical absorption thresholds differ, however, indicating that nanofibrous mats of titania can be selectively developed for different applications in catalysis and photochemistry.
Characterization of Absorbent Flow Rate in Towel and Tissue
Authors: Beuther Paul D. , Veith Michael W. , Zwick Kenneth J.
Published: November 2018

The quality of a paper towel is often judged based on how quickly it can wipe up a spill. However, the test methods currently available cannot repeatably measure significant differences in absorbent rate between samples. Recent round-robin testing evaluations by TAPPI and CEN organizations have shown that past methods, such as ASTM D5802–95 and TAPPI T561-pm [1], are unreliable due to high variability. The reasons for the lack of repeatability are unclear. The relation between the wicking mechanism and the fundamental absorbent properties needs to be better understood. This paper uses x-ray imaging to show the overall flow characteristics of fluid absorption within a towel, and compares the results to model predictions to show which parameters are important to the process. From this understanding, a revised test method is proposed that provides adequate statistical discernment of absorbent rate properties of tissue on a simple lab-bench scale device.
An Infra-Red Heating Based Fast Method of Moisture Content Measurement and Its Application to Measure Blend Proportion of Polyester-Viscose Woven Fabrics
Authors: Kothari V.K. , Bal Kausik
Published: November 2018

Moisture content values of plain woven fabrics of polyester-viscose blended yarns were measured using standard conditioning procedures as well as a new method of preconditioning of samples using infrared heating and subsequent conditioning in a desiccator for a specific conditioning time. The effects of drying time and conditioning time on measured moisture content values were studied and optimization of these parameters were done. Results of the moisture content measurement using these methods show a sufficiently linear relationship between measured moisture content and the proportion of viscose in the fabric samples. The regression analysis showed very high coefficients of determination (above 0.98) in all cases. Regression equations were used to predict the blend proportion of fabric samples from the moisture content data. It was found that even the moisture content values using a shorter conditioning time of 60 minutes and even 10 minutes yielded correct prediction with a maximum error of magnitude less than 3.0 in blend percentage values.
Preparation of Chitosan Biguanidine Hydrochloride and Application in Antimicrobial Finish of Wool Fabric
Authors: Zhao Xue , Qiao Zhen-Zhen , He Jin-Xin
Published: November 2018

Chitosan biguanidine hydrochloride (CGH) has been synthesized by the guanidinylation reaction of chitosan with dicyandiamide. Its synthetic mechanism was discussed. The structures of CGH were characterized by FT-IR and 13CNMR. In this study, we used citric acid (CA) as a crosslinking agent, mixed with CGH to perform a pad-dry-cure treatment on wool fabric to study its antimicrobial effects with the help of scanning electron microscopy (SEM). The result showed that there was no obvious sign that CGH adhered to the wool fabric if the wool fabrics were not oxidized by hydrogen peroxide. The surface crosslinks of the oxidized wool fibers were relatively coarse, which beneficial for the antimicrobial and antiseptic effects of the wool fabrics. Key words: chitosan biguanidine hydrochloride; synthesis; wool; antimicrobial
How is Frayed Fiber Generated during Refining Process? (Identification of Frayed Fiber under High Resolution Microscope)
Authors: Chen Yuhe , Nazhad Mousa M.
Published: November 2018

The objective of this study is to characterize frayed fiber[1] under high resolution microscope to unveil fiber fraying. Based on observation with high resolution microscope, the classification of frayed fibers has been done to contribute to clarifying fiber fraying mechanism. One rectification on previous recognition of frayed fiber has been made to indicate that the dominating cases for fiber fraying are many fibers fraying in one point instead of single fiber fraying at fiber cut site as previously reported[1]. Thus the rectification/removal of fallacious knowledge of frayed fiber favors to clarify this issue. It is further indicated that the unveiling or clarification of fiber fraying mechanism is mainly based on the integration between classification of frayed fiber and traditionally proven effects of refining on various fiber changes from LC to HC refining process. Thus, a latest and newly-built theory responsible for fiber fraying during refining process has been proposed in this paper. With convincing reasoning and speculation, this newly established theory proposed in this paper could go through various visible phenomena and effects of frayed fibers as published earlier[1].

This theory proposes that frayed fibers are generated based on the integration of Ȝsplittingȝ and Ȝlocally high consistencyȝ mechanisms. In other words, the intensive external fibrillation responsible for Ȝsplittingȝ and Ȝlocally high consistencyȝ theory is one of the most important effects on refining on frayed fiber generation. Therefore, the origin of fiber fraying could be the intensive external fibrillation(LC refining at high energy) integrated together with certain fiber type (SW), the methodology of fiber processing(BSKP), refiner type(Escher Wyss) and friction between fibers and equipment. This theory further indicates that any intensive external fibrillation equivalents generated in any conditions other than LC refining at high energy also permit fiber fraying generation.
Computational and Experimental Investigation of Moisture Transport of Spacer Fabrics
Authors: Borhani Sedigheh , Seirafianpour Safora , Ravandi Seyed Abdolkarim Hosseini , Sheikhzadeh Mohammad , Mokhtari Reza
Published: November 2018

This paper investigates the moisture transfer behavior of spacer fabrics. Spacer structures are knitted fabric constructions comprising two separate fabrics which are joined together by spacer threads. In order to investigate the dynamic moisture transfer of spacer fabrics, an experimental apparatus was developed which made the simulation of human body sweating possible.

In the experimental section, the influence of some parameters such as the kind of spacer threads and also heat setting under drawing on moisture transport properties is investigated. Heat setting under drawing affects air permeability, thickness and porosity of spacer fabrics. The Results showed that water vapor produced by sweating can be easily and quickly transferred from the skin to the outer surface to keep the skin dry. In the computational section, a mathematical model was developed to describe moisture transport behavior of spacer fabric. The model was in high good agreement with the observations in the experiments.
Feasibility of Electrospun Polydioxanone — Monocyte Chemotactic Protein-1 (MCP-1) Hybrid Scaffolds as Potential Cellular Homing Devices
Authors: Smith Matthew J. , White Kimber L. , Bowlin Gary L.
Published: November 2018

A novel cellular homing/chemokine delivery system was developed, in which electrospun polydioxanone (PDO) scaffolds infused with Monocyte Chemotactic Protein-1 (MCP-1) were fabricated and examined for their potential to influence macrophage infiltration/adherence and for their potential to provide extended chemokine release. Over the course of 120 hours, MCP-1 released into supernatant peaked at 24 hours and was detectable by enzyme-linked immunosorbent assay (ELISA) when added to PDO solutions prior to electrospinning at 3000 ng/ml. PDO/MCP-1 hybrids were characterized for biological activity using a test tube ELISA procedure assessing macrophage adherence/infiltration of scaffolds. Results demonstrated an increasing dose-responsive trend with increasing MCP-1 concentration. These initial investigations suggest such hybrid materials have significant potential for use in and improvement of in situ tissue regeneration applications by acting as cellular homing devices.
Antimicrobial Properties and Release Profile of Ampicillin from Electrospun Poly(εepsilon;-caprolactone) Nanofiber Yarns
Authors: Liu Hang , Leonas Karen K. , Zhao Yiping
Published: November 2018

Poly(εepsilon;-caprolactone) (PCL) electrospun fibers containing ampicillin sodium salt have been produced and twisted into nanofiber yarns. The fiber diameters and crystallinity, the in vitro antimicrobial properties of the yarns, and the in vitro release of ampicillin from yarns containing various ampicillin concentrations are studied. Decreased fiber diameters and reduced diameter variation are observed with the addition of ampicillin salt into the polymer solution. The results from the zone of inhibition test of the yarns against both gram-positive Staphylococcus aureus and gram-negative Klebsiella pneumoniae indicate that the released ampicillin retains its effectiveness after the production processes, therefore the as-spun yarns are antimicrobial active. A burst release of ampicillin from the yarns has been observed in the first hour, and the release is almost completed in 96 hours. The burst release is believed to be due to the low compatibility of ampicillin with PCL, the accumulation of ampicillin on fiber surface and the small fiber diameters. An empirical release model is developed to describe the release profile. The results indicate that the electrospun nanofibers yarns will have a great potential to be used for biomaterials, such as surgical sutures, to decrease the surgical site infection rate.
Effect of Wool Components in Pile Fabrics on Water Vapor Sorption, Heat Release and Humidity Buffering
Authors: Gibson Phillip W.
Published: November 2018

Experimental measurements of water vapor sorption and desorption in wool/polyester blend fabrics are used to assess associated changes in temperature and heat flux during varying relative humidity levels. The results aid further development and adoption for military applications of cold-weather wool blend fabrics that are more flame resistant and warmer than 100% polyester garments. Two types of bi-sided fabrics were tested: 1) thin knit fabrics designed to be worn next to the skin, usually as undergarments, and 2) thick fleece mid and outer layers with 100% wool on the outer face and 100 % polyester on the inner surface. The following issues were addressed: 1) the effect of wool content on the knit fabrics, 2) the effect of fabric orientation on both the knit and the fleece fabrics, and 3) the effect of durable water-repellent treatment on the fleece fabrics.
Influence of Hot Multistage Drawing on Structure and Mechanical Properties of Nylon 6 Multifilament Yarn
Authors: Rahbar Ruhollah Semnani , Mojtahedi Mohammad Reza Mohaddes
Published: November 2018

The effect of hot multistage drawing conditions on the structure and properties of nylon 6 fibers was investigated by varying second stage draw ratio. Total draw ratio was changed from 3.3 to 5.775 to clarify the structural changes in nylon 6 fiber at a broad range of draw ratio. The structural development of the fibers was studied with FTIR spectroscopy, differential scanning calorimetry (DSC), optical microscopy, and tensile testing. A continuous drop of the γ crystalline form content is observed as a function of draw ratio, in parallel with an increased content of α crystalline phase. The γ crystalline phase vanished completely at draw ratio of 4.62. Increasing draw ratio caused an increase in birefringence and no significant change occurred in crystallinity for the drawn nylon 6 fibers. Deformation behavior of drawn nylon 6 fibers has been explained in terms of applied thermal treatment and mechanical deformations which occurred in each step of multistage drawing.
Development of the Predictive Models for the Fabric Water Vapor Resistance
Authors: Irandoukht Sara , Irandoukht Akbar
Published: November 2018

The water vapor transport properties of textile fabrics are of considerable importance in determining thermal comfort properties of clothing systems. There are different standard test methods available for measuring water vapor transport properties of fabrics. They are either time consuming or expensive methods. Objective of this work is to determine water vapor transmission resistance of the fabric using other properties of the fabric in such a manner that one can predict water vapor resistance. Both linear and nonlinear models were considered and different measures of model adequacy including residual sum of square, maximum absolute deviation and average absolute deviation were calculated. Using linear regression techniques, several statistically acceptable linear models were developed. The results revealed that several non-linear models can predict the water vapor resistance better than linear models.
New Methods to Electrospin Nanofibers
Authors: Chase George G. , Varabhas Jackapon Sunthorn , Reneker Darrell H
Published: November 2018

Electrospinning from a single jet is commonly used to produce very fine polymeric fibers. The mass production rate of the electrospinning from a single jet is relatively low. Alternative methods to launch multiple jets and increase production rates are described here. Few variations on the electrospinning process are reported in literature. In this paper we discuss three novel methods to launch polymer jets via electric fields. Multiple pendant drop electrospinning jets from porous tubes produced fibers with average fiber diameter smaller than 400 nanometers. Bubble launched electrospinning and blown-film methods also result in multiple jets but of larger fiber diameters. These processes have not been optimized to produce small fibers. The three methods here have production rates on the order of 0.03 to 9.00 g/hr per jet. These methods should be scalable.
Influence of Mercerization on Micro-structure and Properties of Kapok Blended Yarns with Different Blending Ratios
Authors: Liu Jie , Wang Fumei
Published: November 2018

To investigate the effect of mercerization on micro-structure and the properties of kapok/cotton blended yarns. FTIR spectra and x-ray diffraction (XRD) results, moisture regains and mechanical properties of blended yarns were compared before and after mercerization. The results show that mercerization treatment did not have an obvious effect on chemical compositions of cellulose, but did lead to decreasing on crystallinity of blended yarns, and transformed certain portion of cellulose I into cellulose II. When the NaOH concentration increased from 180g/L to 250 g/L, the strengths of blended yarns increased and elongations at breaking declined, and the extent of changes were lessened gradually with the increase of kapok fiber content, when the NaOH concentration further reached 280g/L, the strengths of blended yarns with high content of kapok fiber dropped dramatically, and elongations at breaking increased gradually, while hygroscopicities of blended yarns increased significantly. Different from cotton fiber, a more moderate alkali treatment condition should be chosen in mercerization process for kapok fiber.
Control of Inter-fiber Fusing for Nanofiber Webs via Electrospinning
Authors: Raghavan Bharath K. , Coffin Douglas W.
Published: November 2018

Electrospinning provides a viable method to produce both single fibers and mats of nonwoven fibers. For a nonwoven mat, fusing of the fibers at intersections produces an integrated structure. The ability to spin fibrous mats of nanofibers with and without fusing between the fibers is demonstrated using poly(ethylene oxide) (PEO) fibers. The fusing was controlled by adjusting the amount of water vapor in the surrounding environment. Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM) images were used to evaluate the percent of fused fibers in the mat and the diameters of fibers. The major finding of this work is that fusing of fibers can be controlled during formation of a nanofibrous mat via electrospinning in a controlled environment.
The Influence of Knitted Fabrics’ Structure on the Thermal and Moisture Management Properties
Authors: Onofrei Elena , Rocha Ana Maria , Catarino André
Published: November 2018

This paper studies the influence of fabric's structure on the thermal and moisture management properties of knitted fabrics made of two types of yarns with thermo-regulating effect: Coolmax® and Outlast®. The main purpose of this study was the selection of the most adequate fabric, to be used in summer and winter sportswear. The results demonstrated that some properties, such as, thermal properties, diffusion ability, air and water vapor permeability are influenced by both raw material type and knitted structure parameters. Wicking ability is influenced to a greater extent by the knitted structure, while the drying ability is primarily determined by raw material and to a lesser extent by the knitted structure parameters. Outlast® fabrics are preferred candidates for warmer climate sportswear, particularly due to their lower thermal resistance, higher thermal conductivity and absorptivity, air and water vapor permeability. When considering sportswear for colder weather, Coolmax® based structures seem to be the best choice. These findings are an important tool in the design of a sportswear product tailored to the different body areas thermal and moisture management requirements.
Cellulose Submicron Fibers
Authors: Uppal Rohit , Ramaswamy Gita N.
Published: November 2018

In order to manufacture cellulose submicron fibers, electrospinning of cellulose was tried with different solvents. Alpha-cellulose did not dissolve in 6% (w/w) sodium hydroxide/4%urea aqueous solution. Alpha-cellulose solution in 85% phosphoric acid was not spinnable at an applied voltage between 15kV to 25 kV and at a spin length of 4 to 6 inches. Electrospinning of alpha-cellulose in N-methylmorpholine-N-oxide/N-methyl-pyrrolidinone/water solvent mixture could be performed at an applied voltage of 28 kV and at a spin length of seven inches during spinning and at an ambient temperature of 380C. The degree of crystallinity of the cellulose submicron fibers was found to be 37.88%. The number average fiber diameter of cellulose submicron fibers from 1.25% (w/w) cellulose solution in the N-methylmorpholine-N-oxide/N-methyl-pyrrolidinone/water solvent was found to be 207 nm and the number average fiber diameter of cellulose submicron fibers from 2.5% (w/w) cellulose solution in the N-methylmorpholine-N-oxide/N-methyl-pyrrolidinone/water solvent mixture was found to be 243 nm.
The Effect of Spectrophotometer Geometry on the Measured Colors for Textile Samples with Different Textures
Authors: Kandi Saeideh Gorji
Published: November 2018

Spectrophotometers are usually built based on one of these two kinds of geometry; d/8 (diffuse/8) and 45/0. Considering that measured or observed colors depend on the illuminating and viewing conditions, the 45/0 spectrophotometer geometry or d/8 geometry affects the results. In addition, the sample characteristics such as gloss or texture can also influence the measuring results. Therefore, the effect of geometry will be affected by the characteristics of the sample.

In this paper, the effect of spectrophotometer geometry on the result of color measurement is investigated for textile samples with different types of texture. In addition, the effect of texture on the measured colors was compared for two geometries. To this end, 63 polyester samples contained of 9 color centers each of them has 7 different types of texture were used. The spectral reflectance data of the fabrics were measured using two spectrophotometers with different geometry; d/8 and 45/0. Other parameters of the two measuring systems such as the aperture size, laboratory conditions, the sample's direction in front of the spectrophotometer and the number of specimen's layers were equal. The measured values of two instruments were compared. It was shown that the spectrophotometer geometry influences the color coordinates of the samples. The d/8 spectrophotometer with include mode usually gives larger lightness values. C* and H* values are affected by the type of spectrophotometer and this effect is dependent on the color center of the sample. In another part of the present study, the color change via the texture difference was evaluated for each of the two geometries, and the obtained results were compared with each other. It was found that the surface texture of the sample influences the measured color from 0.4 to about 4.8 CIEDE2000 (1:1:1) unit for both two types of the spectrophotometer. Moreover, as same as d/8 geometry, the color change via the texture which is measured by 45/0 shows no acceptable correlation with visual assessments.
Theoretical and Experimental Estimation of the Stored Energy of Plain Knitted Fabrics Using Yarn Pullout Test
Authors: Asayesh Azita , Niazkhani Elaheh , Jeddi Ali Asghar Asgharian
Published: November 2018

The yarn pullout test is a suitable method for investigating the internal mechanical properties of the fabric structure which is established during the weaving or knitting process. In this study, a theoretical model is presented to estimate the stored energy of plain-knitted fabrics which is determined using yarn pullout. The model can predict the stored energy in the fabric, based on the fabric dimensional properties of stitch length and yarn contact angle using force balance analysis. Moreover, in order to evaluate the suggested model, three types of plain-knitted fabric from cotton, cotton/polyester and cotton/nylon with three different stitch lengths were produced and subjected to pull-out tests. Comparison between experimental and theoretical results, demonstrates a reasonable prediction. The results show that the cotton/polyester fabric has the maximum stored energy, because of its higher yarn to yarn friction coefficient. It was also found that, the increase in fabric's loop length leads to a decrease in the fabric's stored energy.
Alkali Extraction of Kraft Pulp Fibers: Influence on Fiber and Fluff Pulp Properties
Authors: Lund Kristoffer , Sjöström Karin , Brelid Harald
Published: November 2018

The importance of hemicelluloses for the papermaking properties of pulp fibers is well documented. In the patent literature, it can be seen that there is also an interest in this type of modification of pulp fibers for use in absorption products. In this study, a Scandinavian softwood kraft pulp and a birch kraft pulp were alkali extracted at 3 different concentrations of NaOH (2%, 4% and 8% NaOH in the suspension). The alkali extraction removed a large part of the hemicelluloses from the pulp fibers and decreased the content of the charged groups. After extraction, the pulps were dried in the form of sheets (approx. 600 g/m2). The alkali extracted pulp fibers exhibited a greater decrease in swelling when re-wetted than untreated pulp. A significant increase in the curl index after extraction with 4% and 8% NaOH was also noted. The tensile strength index of the formed sheets increased at the lowest concentration of NaOH and, at the higher concentrations, a decrease was observed. The pulp sheets were dry defibrated at different defibration intensities and the performance of the resulting pulps in fluff pulp applications was studied. The air-laid fiber networks of softwood pulp fibers showed higher network strength than the networks of birch pulps. The birch pulp extracted at the highest alkali level tended to give the highest network strength. The results from the network strength tests also indicated that the increased curl of the fibers from the softwood pulp extracted at the highest alkali level rendered a more flexible fiber network. In water absorption tests, the alkali treated softwood fibers tended to give networks with a somewhat enhanced water holding capacity under pressure.
Grey Relational Analysis to Determine the Optimum Process Parameters for Open-End Spinning Yarns
Authors: Hasani Hossein , Tabatabaei Somayeh Akhavan , Amiri Ghafour
Published: November 2018

This article focuses on an approach based on the Taguchi method with grey relational analysis for optimizing the process parameters for open-end spun yarns with multiple performance characteristics. A grey relational grade obtained from the grey relational analysis is used to optimize the process parameters. Optimal process parameters can then be determined by the Taguchi method using the grey relational grade as the performance index. CVm%, hair number per meter, and tenacity of yarn were selected as quality characteristics. Using these characteristics, the process parameters, including rotor speed, rotor diameter, opener speed, yarn linear density and navel type are optimized. The raw materials used in this investigation were cotton fibers (35%) and cotton waste (65%) collected from ginning machines. The Experimental results show parameter rotor speed has the most significant effect on the multiple performance characteristics.
Preparation and Characterization of Porous TiO2 Fibers and Their Photocatalytic Activity
Authors: Gao Dawei , Wang Qingqing , Qiao Hui , Cai Yibing , Huang Fenglin , Wei Qufu
Published: November 2018

TiO2 fibers were successfully prepared by combining electrospinning and calcination processes without using the conventional sol-gel method. Polymethyl methacrylate (PMMA) and tetrabutyl titanate (TBT) were used as TiO2 precursor blended with chloroform to form a homogeneous solution for preparing PMMA/TBT composite fibers. The electrospun fibers were calcinated at 500 °C for 4 h in air atmosphere to obtain TiO2 fibers. XRD, SEM TEM and Brunauer-Emmett-Teller (BET) were used to study structures and morphology of the PMMA/TBT and TiO2 fibers. The photocatalytic property of TiO2 fibers was evaluated by photocatalytic degradation of methyl orange (MeO) under UV irradiation. The results demonstrate that mesoporous TiO2 fibers with larger specific surface area possessing pure anatase phase were successfully prepared and the average diameter of PMMA/TBT fibers decreased from 1.5 μm to 1.0 μm after calcination. The TiO2 fibers show high photocatalytic reactivity in photodegradation of MeO solutions.