Synthesis, polymerization and wool coating studies of 3-iso-butylpyrrole and 3-iso-pentylpyrrole

In a four-step method starting from pyrrole, the synthesis of 3-iso-butylpyrrole and 3-iso-pentylpyrrole, was achieved in 45 and 44% yields, respectively. Polymerization studies of these branched alkyl pyrroles are described and the results compared with those obtained for the unbranched structural isomers n-butyl and n-pentylpyrrole. A series of conductive textiles were produced by the chemical polymerization of the iso-alkylpyrroles using both solution and vapour polymerization techniques. Fabrics coated with poly-iso-alkylpyrrole formed using the solution polymerization method had a lower surface resistance than those formed using the vapour polymerization method. These conductivity results were in direct contrast to those previously obtained for 3-n-alkylpyrroles on fabrics. A remarkable crystal-like growth on the surface of the textile fabric was observed when solution polymerization of 3-iso-pentylpyrrole was employed—reinforcing the notion that subtle changes in monomer structure can drastically affect bulk polymer properties.

A comparison of pilling results tested with the ICI pill box and a new perspex™ pill box

Identical single jersey wool knit fabrics produced inconsistent results when tested on the same type of ICI pill box in 4 independence testing laboratories.  The hypothesis formulated to investigate this event was that continued pilling testing in the ICI pill box changes the frictional properties of the cork liners, resulting in the difference pilling ratings.  The aim of this study was to decrease the inconsistencies in the pilling results by replacing the conventional cork lined pill box with a Perspex^TM pill box.  The smae or similar pilling results found for several of the knit facots tested in the two difference pill boxes, while for others there were some significant differences found.  In addition, while using the Perspex^TM pill box observations of the movement of the pilling tubes during testing provided evidence of greater fabric-to-fabric abrasion, rather the expected high degree of fabric-to-cork abrasion (or fabric-to-Perspex^TM) during pilling testing.

Measurement precision and evaluation of the diameter profiles of single wool fibers

A recent model of the Single Fiber Analyzer 3001 (SIFAN3001) was firstly employed to obtain the single wool fiber diameter profiles (SfFDPs) at multiple orientations. The results showed that using SIFAN3001 to measure fiber diameter at four orientations for 50 single fibers randomly sub-sampled from each mid-side sample can produce average fiber diameter profiles (AS fFDPs) of fibers within staples. Within the testing regime used, the precision estimates for the total samples were ±1.3 µm for the mean fiber diameter of staples and 1.4 µm for the average fiber diameter of the AS fFDPs at each scanned step in the diameter profile. The mean diameter ratio (ellipticity) obtained from the four orientations was 1.08±0.01, confirming that the Merino wool fibers under review were elliptical rather than circular. The elliptical morphology of wool fibers and the precision of the fiber diameter measurement at each point along a fiber will be considered in the development of a mechanical model of Staple Strength testing.

An experimental study on fabric softness evaluation

Purpose – To examine a simple testing method of measuring the force to pull a fabric through a series of parallel pins to determine the fabric softness property.

Design/methodology/approach – A testing system was setup for fabric pulling force measurements and the testing parameters were experimentally determined. The specific pulling forces were compared with the fabric assurance by simple testing (FAST) parameters and subjective softness ranking. Their correlations were also statistically analyzed.

Findings – The fabric pulling force reflects the physical and surface properties of the fabrics measured by the FAST instrument and its ability to rank fabric softness appears to be close to the human hand response on fabric softness. The pulling force method can also distinguish the difference of fabrics knitted with different wool fiber contents.

Research limitations/implications – Only 21 woven and three knitted fabrics were used for this investigation. More fabrics with different structures and finishes may be evaluated before the testing method can be put in practice.

Practical implications – The testing method could be used for objective assessment of fabric softness.

Originality/value – The testing method reported in this paper is a new concept in fabric softness measurement. It can provide objective specifications for fabric softness, thus should be valuable to fabric community.

A comparative study of the mechanical properties of wool and alpaca fibres

This study reports the latest research into alpaca and wool fibres. In particular, those properties that have received little attention in research literature have been examined. They include single fibre abrasion and bending fatigue, single fibre tensile properties, as well as resistance to compression behaviour. These properties are important because they affect the softness and pilling propensity of these fibres and the resultant fabrics. Clean wool and alpaca fibres were used in this study. Fibre abrasion/bending fatigue measurements were carried out using a Textechno FIBRESTRESS instrument. The resistance to compression (RtC) tests were carried out according to Australian Standard AS3535-1988. The results indicate that wool and alpaca fibres behave quite differently, even though both fibre types are of animal origin. Wool fibre resistance to compression decreases as fibre diameter increases while the opposite appears to occur for alpaca fibres. For both wool and alpaca the number of abrasion/bending cycles at fibre break increases with an increase in fibre diameter, it takes longer to break the alpaca fibres. Reasons for these differences have been postulated based on differences in fibre surface and structure between alpaca and wool.

The measurement precision and evaluation of the diameter profiles of single wool fibres

A recent model of Single Fibre Analyser 3001 (SIFAN3001) was firstly employed to obtain the single wool fibre diameter profiles (SfFDP’s) at multiple orientations. The results showed that using SIFAN3001 to measure fibre diameter at four orientations for 50 single fibres randomly sub-sampled from each mid-side sample can produce average fibre diameter profiles (ASfFDP’s) of fibres within staples. Within the testing regime used, the precision estimates for the total samples were ±1.3µm for mean fibre diameter of staples and ±1.4µm for average fibre diameter of the ASfFDP’s at each scanned step in the diameter profile. The mean diameter ratio (ellipticity) obtained from the four orientations was 1.08±0.01, confirming that the Merino wool fibres under review were elliptical rather than circular. The elliptical morphology of wool fibres and the precision of fibre diameter measurement at each point along a fibre will be considered in the development of a mechanical model of Staple Strength testing.

One-bath union dyeing of wool/polytrimethylene terephthalate blends

The one-bath dyeing of blends of polytrimethylene terephthalate (PTT) staple and wool has been investigated. The exhaustion of selected Terasil disperse dyes on PTT fibre and Lanasol reactive dyes on wool was measured as a function of temperature, together with the cross-staining of the Terasil dyes on the wool component and the Lanasol dyes on PTT component. Most Terasil disperse dyes achieved satisfactory dye uptake on PTT at 110 °C, whereas on conventional polyester (polyethylene terephthalate) temperatures of up to 130 °C are required. An optimised union-dyeing technique for wool/PTT blends was developed which minimised the staining of Terasil disperse dyes on wool and produced dyed goods with high levels of wet colour fastness. Carriers were not required to enhance the dyeability of PTT at low temperatures. The wool component appeared to be protected against damage at 110 °C by the reactive dyes. The results indicate the potential for blending PTT fibre and wool to produce fabrics that are easier to dye at lower temperatures than conventional wool/polyester blends.

Superhydrophobic fabrics prepared by silica coating

In this work, a silica sol prepared by co-hydrolysis and co-condensation of TEGS (Tetraethylrthosilicate) and alkyl silane under alkaline condition was applied to polyester, wool, and cotton fabrics. The water contact angle measurement indicated considerable increase in the surface hydrophobicity of the sol-treated fabrics. Five different alky silanes were used, namely methyltritthoxysilane (MTES), pheryl triethoxysilane (PTES), n-octyltricthoxysilane (OTES), hexadecyl trimethoxysilan (HDTMS), and tridecafluorooctyl triethoxysilane (FAS), and the water contact anglc (CA) for the coated fabrics ranged between 1300 and 174°. The alkyl silane used influenced the CA valuc, and the silica coating from FAS, HDTMS and PTES snowed CA value greater than ISO', indicating the formation of superhydrophobicity. The fabric coated by the fluorinated silica (TEOS/FAS) has a water contact angle as high as 174°. The treated polyester fabric showed a slightly higher CA value than the wool and cotton fabrics, under the same coating condition.
The coating surface was characterized by SEM, EDX, TEM, FTlR, XPS and AFM. The results showed that silica nanoparticles with thc sizc in the range of 50-ISOnm werc formed in the cohydrolyzed silica sol, and these particles had a core-shell structure with many alkyl groups gathering on the surface region. The formation of superhydrophobic surface was attributed to the nano-structured surface coating with a low surface energy.

A comparison of the ICI Pillbox and the Random Tumble Methods is assessing pilling and appearance change of worsted spun cashmere and cashmere-wool blend knitwear

This study evaluated the differences between two international test methods on the assessment of pilling and appearance change of worsted spun cashmere and superfine wool knitwear and their blends. Differences between the standard ICI Pill Box Method and the Random Tumble Method were found in both the significance and magnitude of resistance to pilling and appearance change and the amount of fabric mass loss of worsted spun cashmere and cashmere superfine wool blend knit fabrics. The ICI Pill Box Method differentiated to a greater extent the effects of wool type and blend ratio of cashmere and wool compared with the Random Tumble Method. Generally the addition of cashmere or low crimp superfine wool resulted in fabrics being more resistance to pilling and appearance change compared with fabrics made from high crimp superfine wool. This was associated with increased fabric mass loss when assessed by the ICI Pill Box Method but not with the Random Tumble Method. KEYWORDS: Cashmere, crimp, wool, pilling, appearance change, knitwear

A study on within-fibre diameter variation of wool

This work established and experimentally validated several models for accurately predicting wool fibre and yarn properties. The results will be useful in fibre selection, and will help predict fibre processing performance and end-product quality.

Super water repellent fabrics produced by silica nanoparticle-containing coating

In this paper, we report on superhydrophobic fabrics (polyester, wool and cotton) produced by a wet-chemical coating technique. The coating solutions were synthesized by the co-hydrolysis of two silane precursors, tetraethyl orthosilicate (TEOS) and an alkylsilane, in an alkaline condition. Without any purification, the as-hydrolyzed solutions were directly used to treat fabrics, and the treated fabrics had water contact angles (CA) as high as 170º and sliding angles (SA) as low as 5º. Three alkylsilanes have been used for the synthesis of the coating solutions, and all contain three hydrolysable alkoxyl groups and one non-hydrolysable alkyl, but with different chain lengths (C1, C8 and C16). It was found that the CA value increased with an increase in the alkyl chain length, while the SA showed a reverse trend. When the functional group had a C16 alkyl, the treated fabric surfaces were highly superhydrophobic, with the CA not being affected much by the fabric type, while the SA values were slightly affected by the original wettability of the fabric substrates. The superhydrophobic feature was attributed to a highly rough surface formed by the particulate coating. Aside from the superhydrophobicity, the influence of the coating on the fabric softness was also examined.

Objective pilling evaluation of nonwoven fabrics

A pilled nonwoven fabric image consists of brightness variations caused by high frequency noise, randomly distributed fibers, fuzz and pills, fabric surface unevenness, and background illumination variance. They have different frequency and space distributions and thus can be separated by the two-dimensional dual-tree complex wavelet transform reconstructed detail and approximation images. The energies of the six direction detail sub-images, which capture brightness variation caused by fuzz and pills of different sizes, quantitatively characterize the pilling volume distribution at different directions and scales. They are used as pilling features and inputs of neural network supervised classifier. The initial results based on a nonwoven wool fabric standard pilling test image set, the Woolmark®‚ SM 50 Blanket set, suggest that this objective pilling evaluation method developed by the combination of pilling identification, characterization method and neural network supervised classifier is feasible.

Ultrasonic treatment of wool

These ultrasonic cleaning trial results for stain removal and fibre property changes look at wool scouring and laundering, and examine the use of ultrasonic irradiation during wool cleaning with an aim to improve the cleaning process and reduce its impact on the environment. It contains fibre images, single fibre tensile and bending abrasion results.

Effect of fibre, yarn and knitted fabric attributes associated with wool comfort properties

In this replicated experiment, we investigated the comfort properties of single jersey fabrics composed of cashmere in blends with superfine wools of different fibre curvature (crimp) where the fibre diameter of the wool and cashmere were tightly controlled. The 81 fabrics were evaluated using the Wool ComfortMeter (WCM) which has been calibrated using wearer trials of wool knitwear. General linear modelling determined the best prediction models for log10 transformed fabric WCM values using 27 fibre, 16 yarn and 30 fabric attributes. Tighter fabrics were less comfortable. Progressively blending cashmere with wool progressively increased comfort assessment. The WCM was able to detect differences between fabrics which were more supple and springy, thinner and lighter, and were composed of more elastic, uniform and stronger yarns. Together these attributes explained 82% of the variance in WCM value.

Relationship between wearer prickle response with fibre and garment properties and Wool ComfortMeter assessment

The prickle evoked by 48 knitted fabrics was assessed by wearers under a defined evaluation protocol. The relationship between the average wearer prickle score and known properties of constituent fibre, yarns and fabrics and fabric evaluation using the Wool ComfortMeter (WCM) was determined using linear modelling. After log transformation, the best model accounted for 87.7% of the variance. The major share of variation could be attributed to differences between mean fibre diameter (MFD) and WCM values. Low prickle scores were linearly associated with lower MFD, lower WCM and lower yarn linear density. There was an indication that yarn twist affected prickle scores and that fabrics composed of cotton evoked less prickle. Measures of fibre diameter distribution or coarse fibre incidence and other fabric properties were not significant. The analysis indicates that wool garments can be constructed to keep wearer assessed prickle to barely detectable levels and textile designers can manipulate a range of parameters to achieve similar wearer comfort responses.