Knitted Research Articles

The Culture of Knitting

The Culture of Knitting

Study on Dyeing Behavior of Cotton/Organic Cotton Knitted Fabrics

Organic cotton is grown using methods and materials that have a low impact on the environment. Organic cotton is grown and processed without toxic chemicals that can be absorbed easily when in contact with the user's skin. This paper describes the dyeing behavior of organic cotton vs conventional cotton to find what will be the significance between them. The ring spun yarns of 40s combed organic (GOTS certified) and ordinary cotton were produced with similar parameters like beating point and settings. Knitted fabrics were produced with similar loop length and weight using organic and ordinary cotton yarn. Both the fabrics were processed in GOTS certified Processing unit using reactive dyes in soft flow machine in single dye bath. Processed fabrics were tested for colour fastness to washing, water, rubbing, perspiration and light. Colour difference and strength were also measured using Spectrophotometer (DATACOLOUR). Presence of metals were also analyzed in both the processed fabrics and reported here.

Suture-reinforced polydioxanone-elastin for tissue engineering of small-diameter vessels: a feasibility study

Objective To investigate the feasibility of constructing sutuze-reinforced polydioxanone(PDS)multilayer small-caliber artificial scaffolds and determine its biomechanical properties.Methods 7-0PDS fibers were woven into a stent with 4 mm inner diameter.The influence of different weaving angle and knitting structure on the mechanical properties were investigated.Multilayer scaffolds were constructed using the preparecl PDS stent as the middle elasticity layer and covering it with small intestinal submucosa(SIS).To reinforce the scaffold,the outer two lavers were continuously sutured with 8-0 PDS suture perpendicular to the longitudinal axis.The inner layer of scaffold was coated With collagen sponge which was added with 10%chondroitin sulfate(CS).The biomechanical properties of the scaffold such as burst strength,tensile strength and compliance were tested and compared to those of canine carotid artery.Results 65-degree weaving angle was chosen to construct stent with 4 mm inner diameter and 3 to 5 cm length.These scaffolds had(43.50±8.30)kPa burst strength,(19.10±1.56)N tensile strength,(42.88±3.16)% strain ratio and(5.96±0.87)%/100 mm Hg radial compliance.Conclusion The multilayer scaffolds have satisfactory biomechanical properties that meet the mechanical requirements for in vivo implantation as a tissue engineered blood vessel. Key words: Tissue engineering; Blood vessels; Biomechanics; Polydioxanone

Establishing the Effect of Loop Length on Dimensional Stability of Single Jersey Knitted Fabric made from Cotton/lycra Core Spun Yarn

Munden and earlier workers established that in plain knitted fabrics the fabric dimensional parameters namely Kc, Kw and Ks are constant at dry and wet relaxed state for wool, cotton, orlon and nylon yarns. But in the present study of cotton/lycra core spun yarn single jersey derivative knitted fabrics the values for Kc, Kw and Ks varies with loop length. The ratio of Kc/Kw also varies with loop length. In this paper, Single jersey fabric is produced from Polyester/lycra air-covered yarn with different loop lengths. The study covers about the testing of dimensional properties of the single jersey knitted fabric. After the fabric production, the fabric was dry relaxed. Wales per inch, courses per inch, fabric width, loop length and fabric thickness are all measured. Then the fabric was wet relaxed and tested for the above parameters. Then the samples were heat set at various stretch levels at 180°C. From the study, it was found that the dimension of fabric shows considerable change during wet relaxation. The fabric shows very good appearance when heat set at all stretch levels at 180°C in course direction. The fabric with a loop length of 2.5 mm was found to have better appearance when compared to the fabrics of other loop lengths. In particular 10% stretch level shows a better appearance for 2.5 mm loop length.

An investigation into the properties of cotton/spandex and polyester/spandex knitted fabrics

Very little work has been done in the area of spandex-blend weft knits. This paper presents the findings of knits produced from cotton/spandex- and polyester/spandex-blend knits produced from core spun yarns. The dimensional properties of cotton/spandex knits compare well with those of cotton knits. The behaviour of the loops in both the spandexblend knits in the course direction gives rise to the difference in the properties. The feed yarn tension has insignificant effect.

FLAT KNITTING OF A LIGHT EMITTING TEXTILE WITH OPTICAL FIBRES

Abstract Knitted products have a flexibility that offers many attractive possibilities. Combined with technical fibres, this gives interesting and innovative possibilities. Many technical fibres and yarns has however properties such as high stiffness and brittleness which are difficult to process in the practice of weft knitting. This paper is about the experimental product development of a light radiating textile lamp in which optical fibres are used as the only illumination source. The lampshade is produced on an electronic flat knitting machine with special equipment suitable for the feeding of yarn with high stiffness. The work was divided in two parts: exploring the possibilities to knit the desired shape on one hand and experimenting about knitting with optical fibres as a weft insertion on the other hand. The method is an inductive approach; a literature survey, information from suppliers of knitting production equipment and experimental work on a flat knitting machine at The Swedish School of Textiles, Boras, Sweden. Results show that the diamond shaped structure can be knitted in one piece with transparent monofilament yarns. Furthermore it also shows that difficulties occur when knitting with stiff and brittle optical fibres therefore the paper ends with a discussion with suggestions of how to overcome these challenges.

Fabric Sound Depends on Fiber and Stitch Types in Weft Knitted Fabrics

The purpose of this study is to analyze the characteristic fast Fourier transform (FFT) spectra of weft-knitted fabrics, to investigate the relationship between sound parameters and the mechanical properties of the weft knits, and to determine the effects of fiber type and stitch type on the frictional sound and mechanical properties. The specimens included 12 weft-knitted fabrics made from a combination of 3 fiber types (100% wool, 100% cotton and 49%/51% wool/ cotton) and 4 stitch types (plain, rib, half cardigan and half milano stitch). The rustling sounds of each specimen were recorded and analyzed using FFT analysis including sound parameters such as LPT (level pressure of total sound), Δ L (level difference) and Δ f (frequency difference). We also used Zwicker's psychoacoustic model to calculate the loudness ( Z), sharpness ( Z), roughness ( Z) and fluctuation strength ( Z). In addition, the mechanical properties of the specimens were measured using the Kawabata Evaluation System (KES). The FFT spectra for the weft-knitted fabrics showed different shapes according to the fiber and stitch types. Mechanical properties such as the thickness and weight were correlated with several sound parameters. Fiber type was affected by Δ f and stitch type was affected by Δ L, roughness ( Z), fluctuation strength ( Z) and weight. Both fiber type and stitch type were affected by tensile properties. It is possible, by changing fiber and stitch types of weft-knitted fabrics, to obtain various kinds of knitted fabrics with different frictional sounds.

Knitted comforts and lucky escapes: selected anecdotes from J L S Coulter.

Knitted comforts and lucky escapes: selected anecdotes from J L S Coulter.

Researches and observations concerning biointegration of vascular prosthesis in animals.

In our study we tried to observe and appreciate the quality of anastomosis in case of vascular prosthesis, its tolerance and biointegration degrees. Observations were made on a number of fifteen dogs, different age and rase, and also on a number of five pigs weighing between 50-60 kg. For anastomosis it was used knitted Dacron prosthetic graft with low porosity. Dacron graft was used for iliac arteries and for aorta. The anastomosis was effectuated both in interrupted simple suture and simple continuous patterns. Dacron prosthesis were well tolerated by dogs, species which was monitored during thirty days, but also by pigs which were monitored during sixty days. We did not observe any complications or adverse reactions

Shear Behavior of 3-D Biaxial Spacer Weft Knitted Composite under High Strain Rates

The punch shear behavior of 3-D biaxial spacer weft knitted E-glass/ vinyl ester composite was investigated at quasi-static (0.01/s) and high strain rates ranging from 1200 to 3200/s in wale and course directions respectively. The quasi-static shear behavior was tested on a MTS 810.23 material tester and was compared with high strain rate shear behavior from a modified split Hopkinson pressure bar (SHPB) technique. The experimental results indicate that the shear stiffness, failure stress, and failure strain are rate sensitive both in wale and course directions. The shear stiffness and failure stress increase with the the increase of strain rate. The failure strains along the wale and course directions decrease with increasing strain rate. Furthermore, the shear failure becomes more severe in the course direction than in the wale direction at high strain rates. The damage mode in the wale direction at various strain rates is punch shear failure, while that of the course direction is filament tow breakage and matrix cracks. The unique features of this article are to conduct the punch shear tests at high strain rates successfully using a modified SHPB apparatus for the novel 3-D knitted composite and find the strain rate sensitivity both in shear behavior and failure mode. The results will benefit the structural design of the 3-D knitted composite owing to the higher in-plane tension stiffness and strength of the composite than any other 3-D textile structural composites.

Study of three-dimensional spacer fabrics:: Physical and mechanical properties

Spacer is a three-dimensional knitted fabric consisting of two outer textile substrates which are joined together and kept apart by spacer yarns. Spacer fabrics are used for environmental reasons, which can be used in different product groups such as mobile textiles (car seat covers, dashboard cover), industrial textiles (composites), medical textiles (anti-decubitus blankets), sports textiles and foundation garments (bra cups, pads for swimwear). In this study, the characteristics of different spacer fabrics including low-stress mechanical properties, air permeability and thermal conductivity were investigated. Low-stress mechanical properties obtained by the KES-fabric evaluation system revealed that all tensile, bending and compression properties of spacer fabrics are greatly depending on the type of spacer fabric (warp knit or weft knit), the type of spacer yarn used (monofilament or multifilament), the yarn count of the spacer yarn, the stitch density and the spacer yarn configuration. Air permeability and thermal conductivity of spacer fabric are closely related to the fabric density. This experimental work suggests that carefully selecting the spacer fabric according to the envisaged application is of primary importance.

Radical Lace and Subversive Knitting

Radical Lace and Subversive Knitting

Knitting a Ravelled Sleave

Knitting a Ravelled Sleave

위편성물의 혼용률 및 편환장이 주관적 질감과 선호도에 미치는 영향 -구조방정식 이용-

The purpose of this study is to develop the relationship model among subjective texture and preference of weft knit according to fiber contents of wool/rayon and loop length by integrating previous research work. SPSS and SEM method using AMOS program were used to analyze data which used to correlation matrix to be standardized. The texture of weft knit were classified into 4 categories: irregularity, flexibility, bulkiness, extensibility. The fiber contents of wool/rayon had effect positively on irregularity, bulkiness and extensibility and that had little effect on preference. The loop length had effect positively on irregularity, flexibility and extensibility and that had effect negatively on preference. This measurement model will be input for testing causal research model that can explain how fiber contents of wool/rayon and loop length of weft knit influence on subjective texture.

위편성물에서 Rib stitch와 Milan stitch의 편성결합이 태에 미치는 영향

The purpose of this study is to investigate change of mechanical and physical properties, shape behavior and hand value in weft knit when rib stitch and milan stitch are combined. The knit stitches used in this study are plain stitch, half milan rib stitch, milan rib stitch, <TEX>$2{\times}1$</TEX> rib stitch, <TEX>$2{\times}1$</TEX> half milan rib stitch and <TEX>$2{\times}1$</TEX> milan rib stitch. We analyzed physical and mechanical properties(tensile, bending, shear, compression, surface properties, thickness and weight) of the knit stitches and calculated their primary hand value and total hand value through translational formulas using the KES(Kawabata Evaluation System). The results are as follows; In evaluation of mechanical properties and hand values of knit stitches, plain stitch had the highest flexibility and the lowest T.H.V. as women's winter knit wear. Since <TEX>$2{\times}1$</TEX> rib stitch had too high elongation in one direction, although it had the highest T.H.V, it needs to be careful when plain stitch and <TEX>$2{\times}1$</TEX> rib stitch are applied for women's winter knit wear. Since Milan rib stitch and <TEX>$2{\times}1$</TEX> milan rib stitch had high T.H.V. similarly, it is considered that they are suitable for women's winter knit wear. Specially, when Milan stitch is combined with <TEX>$2{\times}1$</TEX> rib stitch, its shape stability and fullness are contained and flexibility is added on it. Therefore, <TEX>$2{\times}1$</TEX> milan rib stitch can be also applied for women's winter knit wear.

Stick to your knitting

Stick to your knitting

Comparison of the Mechanical Behavior of Plain Weave and Plain Weft Knit Jute Fabric-Polyester-Reinforced Composites

The tensile and impact behavior of jute fabrics—polyester composites–were evaluated as a function of the fabric style (knitted or weaved cloths), fiber weight fraction, and direction of the applied load. The tensile properties of plain-weave-fabric-reinforced composites (PWF) were higher than those of plain weft knit cloth composites (WKT) and were dependent on fiber content and test direction. The properties of the WKT, however, were independent of these variables. The results obtained indicate that the orthogonal fiber alignment of weaved cloths favors anisotropy, while the interconnected loops in knit fabrics favors isotropy. The results also indicate weak fiber-matrix interactions in both fabrics and a better fabric impregnation for the plain weave fabric if compared with that of the knit fabric. The impact strengths of both composites were higher than that of the matrix and were shown to increase with fiber content. WKT-reinforced composites showed better impact absorption capacity than PWF composites. This behavior is attributed to the influence of the weaving pattern of the fabrics and to the differences in fabric impregnation by the matrix.

DEVELOPING FIBROUS MULTIFUNCTIONAL STRUCTURES FOR TECHNICAL APPLICATIONS

Abstract This paper describes a quick prototyping unit for fibrous multifunctional structures which has been set-up at the University of Minho. This unit provides for fast development of technical samples for a variety of special applications, mainly in the areas of health and well-being, sports goods, personnel protection, techno-fashion, the civil construction and building industries, composite materials, and so on. The unit works systematically through the areas of conceptualisation, design and simulation, development, manufacturing and testing of technical and intelligent textile materials and structures, providing solutions for technical problems. New structures are developed for specific applications where special requirements are needed. It provides the best solution in terms of materials, structures, technologies and cost. The technologies involved include advanced CAD systems, FEA (finite element analyses), testing of mechanical properties, permeability, conductivity, microscopy, as well as smallscale- computer controlled manufacturing of yarns, nonwovens, wovens, warp &amp; weft knits, braids and hybrid structures. Special finishings and surface treatments, coating and lamination are also possible. The unit is used for research, education and to provide services for companies in emerging markets for advanced textile materials. Examples of the novel products developed are provided.

A BIPOTENTIOMETRIC FIA SYSTEM FOR DETERMINATION OF VITAMIN C

A bipotentiometric FIA system has been developed for the determination of vitamin C. The system was a single stream manifold, which consisted of a peristaltic pump, a self made injector with internal loop and two Pt-electrodes connected to a PC by serial ADC or parallel ADC interface card. One of the Ptelectrodes was located in the injector before the internal loop, while the other electrodes at the end of the TEFLON reaction tube. The PC was supported with a self-made software for controlling the pump, signal acquisition, processing, and visualisation, and further peak determination, followed by calibration of standard solutions and calculation of sample concentrations. The above FIA-system configuration was applied to determine vitamin C by the injection of sample solution into a stream of potassium hexacyanoferrate (III) solution. The optimum result was achieved with knitted tube reaction of 0.8 mm i.d., 50 cm length, at flow rate 0,64 ml/minute, and consumed 3.6 ml of carrier solution per five injection, and gave linearity range at 0.001 – 0.100 N vitamin C, with the coefficient of correlation 0.9999, RSD peak to peak better than 3.0% and the error of artificial samples were less than 3.4 %. Key Words : Bipotentiometric-FIA, injector with internal loop, module-program, vitamin C

Relations between Fabric Structure and Friction: Part II: Weft Knitted Fabrics

In the earlier part of the series (Jeddi et al., 2003) the authors defined a new index for the structural asperity of woven fabrics and found the relationship between this index and fabric frictional parameters. In this part, the authors develop this definition for weft knitted fabrics and introduce a ‘Fabric Structural Asperity Index’ (FSAI) for interlock gating of knitted structures. This index, which can be explained as the ratio of miss stitches to the total number of needles in a structural knit cell, shows a good relation with frictional resistance parameters of the course over course direction of motion. The experimental results show that the static and dynamic frictional resistances of the course over course motion are higher than the wale over wale motion. The values of frictional forces for different structures have no statistical difference in the wale over wale direction of motion. This paper also studies the effectiveness of the structural cell stitch length and fiber content on the frictional behavior of the fabrics.