• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 23
  • 10
  • 1
  • Tagged with
  • 35
  • 35
  • 9
  • 7
  • 5
  • 3
  • 3
  • 3
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Development of Dual Functional Textile Materials Using Atmospheric Plasma Treatments

Mittal, Khushboo Surender 11 August 2009 (has links)
Glow discharges and low temperature plasmas and their applications have increasingly entered various areas of industrial applications. The textile industry is a developing area for application of atmospheric plasma techniques with significant growth potential. Technological advances made possible by plasma processes can reduce the costs for production by reduction in process times, improve the quality of product, generate products with new surface or bulk properties, and contribute to an environmentally sustainable work environment. A novel dual functional textile material was developed which possesses co-existing hydrophobicity and hydrophilicity on opposite faces utilizing atmospheric pressure plasma. One side of the substrate repels water whereas the other side absorbs water. The sequence and chemistry of the plasma aided side specific treatment of poly (ethylene terephthalate)/ polyurethane blend knitted fabric and cellulose with fluorocompound namely 1, 1, 2, 2- tetrahydroperfluorodecyl acrylate (70- 90%) and 1, 1, 2, 2- tetrahydroperfluorododecyl acrylate (10- 30%) was demonstrated to obtain the dual functionality. Effect of process and device parameters such as variation of (1) flow rate of monomer, (2) flow rate of helium and (3) flow rate of argon, (4) RF power, (5) time of plasma exposure to the fabric, (6) gap between electrodes, (7) prewashing the material before treatments and (8) preliminary plasma treatment on the fabric performance was also studied in this research.
2

Wrinkle Recovery for Cellulosic Fabric by Means of Ionic Crosslinking

Bilgen, Mustafa 21 April 2005 (has links)
When treated with formaldehyde-based crosslinkers, cellulosic fabrics show improved mechanical stability, wrinkle recovery angles and durable press performance, but N-methylol treatment also causes fabrics to lose strength and later to release formaldehyde, a known human carcinogen. We have discovered that ionic crosslinks can stabilize cellulose using high or low molecular weight ionic materials which do not release hazardous reactive chemicals, but at the same time provide improved wrinkle recovery angles as well as complete strength retention in treated goods. We have varied polyelectrolyte, the ionic content of fabrics, and various features of the application procedure to optimize the results and to develop an in-depth fundamental physical and chemical understanding of the stabilization mechanism.
3

Preparation of ionic cellulose for wrinkle resistant fabrics

Vargantwar, Pruthesh Hariharrao 03 May 2007 (has links)
Conventional treatment of cellulosic fabrics by formaldehyde-based cross-linkers provides improved wrinkle recovery angles (WRA) and durable press (DP) performance. But these treatments suffer from strength loss and later release of formaldehyde, a known carcinogen. Ionic crosslinking offers a potential solution to these problems, and has shown improved wrinkle recovery performance in previous studies. In the current novel method of ionic crosslinking for wrinkle resistant fabrics, the cellulosic fabric is treated with salt of mono chloroacetic acid and 3-chloro-2-hydroxypropyl trimethyl ammonium chloride (CHTAC) sequentially or in mixture to form covalently bonded anionic and cationic sites on cellulose, which are durable to washing, and which form inter/intra molecular ionic cross-links. There is no later release of hazardous chemicals involved with this treatment and improved wet WRA are obtained. Fabric treated by this method gained tensile strength and breaking strain compared to the untreated fabric. Different routes for chloroacetate treatment are presented. Pad-dry-pad-cure is the most efficient route and a functional relationship between the anionic content and the process parameters is established. Analytical techniques like confocal microscopy and scanning electron microscopy are used to confirm the morphological changes and occurrence of carboxymethylation reaction in the fiber interior.
4

Novel Reactive Dyes Based on Pyrimidine and Quinoxaline Systems

Horton, Aaron Michael 13 August 2009 (has links)
No description available.
5

Use of Modified Cellulose for the Improvement of Water Repellency

Goli, Kiran Kumar 16 June 2008 (has links)
A novel method is developed for imparting durable water repellency to cotton cellulosic fabrics based on ionic interactions. Most of the traditional water repellent finishing chemicals such as paraffin waxes, pyridinium compounds, formaldehyde based N-methylol crosslinkers, siloxanes and fluoro-carbon polymers are either non-durable to washing or environmentally unsafe or expensive. Our method includes cationization of cotton fabric with 3-chloro-2-hydroxypropyl trimethyl ammonium chloride (CHTAC) followed by subsequent treatment with a salt of stearic acid to form ionic attractions between cationic groups of cationized cotton fabric and anionic groups of stearate anion. These ionic interactions hold the stearate or hydrophobic molecules on the surface of cotton fabric outwards giving durable water repellency without releasing any hazardous chemicals present in almost all other durable water repellent treatments for textiles.
6

Mechanical and physical properties of electrospun nanofibers

Zhang, Shu 13 August 2009 (has links)
The process of electrospinning was utilized to fabricate randomly aigned nylon6 nanofibers and aligned nylon6 nanofibers. Polymer concentration affecting electrospinning was investigated. This parameter was evaluated using degree of crystallinity by differential scanning calorimetry (DSC) as well as visual images produced by scanning electron microscopy (SEM). DSC data demonstrated that more crystals were formed with lower polymer concentrations; SEM images revealed that slimmer fibers were produced by lower concentrations. The mechanical properties of unoriented fibers and aligned fibers were tested on Instron 5544. The result of tensile tests indicated higher Youngâs modulus and tensile strength of aligned nanofibers than that of unaligned fibers. The SEM images at broken edges of fibers illustrated different broken mechanisms of these two forms of nanofibers. The broken mechanism of aligned nanofibers was further confirmed by crystallinity parameters obtained from DSC and fiber diameter shown from SEM images.
7

Novel Supramolecular Polyamides

Saunders, Joshua Daniel 25 July 2005 (has links)
The objective of this research is to use low DP poly(p-benzamide) (PBA) segments, terminated by units forming supramolecular bonds, able to extend the overall DP of the aromatic polyamide. PBA fibers, and the related industrially produced PPTA (Kevlar), exhibit their most interesting ultra-high strength properties only when a considerably large DP (>100) is attained. Use of cumbersome and expensive syntheses and solvents are required to attain DP in the range (~200-300) of industrial interest. Moreover, the fully covalent polymers thus far produced are highly insoluble in common organic solvents. On the other hand, easier processing becomes feasible if the DP of conventional PBA (prepared by the Yamazaki reaction) is increased by supramolecular bonding through ionic or hydrogen bond interactions. The effects of three different binding methods were first investigated on short rigid monomers with promising results the same binding was then used on rigid segments of PBA. The binding methods used two diamine binders triethylenediame (TED) and bipiperidine (Bipip) to form ionic bonds with the monomer, and polymer segments. The last method utilized a 2(6-iso cyanato hexylamino carbonyl amino)-6-methyl-4[1H]pyrimidinone (Upy) end group covalently bonded to the PBA polymer. This end group has the ability to form 4 hydrogen bonds with itself and thus could be used to increase the overall DP of the polymer starting material. This is believed to be the first recorded hydrogen bonded supramolecular interaction in amide type solvents. The novel and revolutionary idea of using low DP segments of PBA to increase the overall DP of polymer could be an industrially viable way to produce the highly sought after industrial polyamides.
8

An Alternative Laundering Procedure to Predict the Durability of Flame Retardant Fabric

Lumley, Amy Catherine 21 August 2003 (has links)
This project set out to determine an alternative laundering procedure to predict the durability of flame retardant fabrics while decreasing the overall cost and time involved for testing. Fabric was washed using conventional methods to be used as standards. These fabrics were characterized by burning characteristics, elemental analysis, fabric weight, percent weight change, shrinkage, color, and strength. Then fabrics were washed using an alternative method and characterized in the same manner. The alternative laundering procedure involved a programmable machine, Quickwash Plus. Parameters on the machine were varied to simulate x number of washings using a conventional industrial wash.
9

USE OF CATIONIZED COTTON FOR TEXTILE EFFLUENT COLOR REDUCTION

KARNIK, POONAM PRAFULL 01 March 2002 (has links)
<p> ABSTRACTKARNIK, POONAM. Use of Cationized Cotton for Textile Effluent Color Reduction.(Under the direction of Dr. Brent Smith and Dr. Peter Hauser) The liquid effluents from the textile industry mainly consist waters colored by thedyes used in the coloring of textile yarns and fabrics. These dyes can be removed by adsorption onto adsorbing materials like cotton. Waste cotton fibers can be cationized using a quaternary ammonium compound like 3-chloro-2-hydroxypropyltrimethylammonium chloride to their cationic form. This cationic form can be used as the adsorption medium for anionic dyes like acid, direct and fiber reactive dyes. <P>
10

Electrophoresis of reduced polypeptides dissolved from Lincoln wool and other animal fibres

Horn, John Christopher January 1986 (has links)
No description available.

Page generated in 0.0546 seconds