José Lucas

Optical Estimation of a Set of Pilling Coefficients for Textile Fabrics

This paper presents the results obtained using an experimental system, based on optical triangulation, which enabled topographic reconstructions of textile fabric surfaces. Consequently, one could evaluate and quantify the pilling formation through the optical estimation of a set of pilling coefficients. The proposed method was found to be precise, robust and systematic, and may constitute an alternative and/or complementary approach to quantify the pilling formation.

Synthesis of poly(3, 4-ethylenedioxythiophene) coating on textiles by the vapor phase polymerization method

In this article, plain weave fabrics of polyester were functionalized by means of a polymeric coating synthesized for high conductivity, using the vapor phase polymerization method. The method is considerably more efficient and sustainable than traditional wet methods and has been previously applied to synthesize poly(3, 4-ethylenedioxythiophene) in yarns and fabrics, using oxidant agents with organic solvents. In this article, aqueous oxidant solutions were used in addition to those based in ethanol, providing textile substrates with high electrical conductance. The effect of the concentration of the oxidant solution on the electrical and mechanical characteristics of the samples was investigated and correlated to their morphology, analyzed by electron microscopy imaging. A strong decrease of the sheet resistivity of the samples with the concentration of oxidant increase was obtained, while the fabrics’ original mechanical tenacity remained unchanged. The sheet resistivity of the samples could be further decreased by a factor of 5 by the application of multiple polymerization layers and was a function of the conjugated polymer content. The effect of washing/drying cycles on the electrical conductance of the samples is presented. The electrical and mechanical characteristics obtained have potential for smart textile applications such as electromagnetic shielding and physiological sensing.

Garment abrasion strength evaluation: a comparative methods study

Purpose – The breaking strength compromises fabric wearing out during wear of garments and is a determining parameter in their useful life. Thus, it is intended to compare the efficacy of each method concerning the understanding of results, which is, the explanation of the phenomenon, namely through statistical models which characterize abrasion strength, measured by each method, as a function of fabric assurance by simple testing (FAST) parameters.Design/methodology/approach – The simulation of abrasion mechanism was done on Martindale wear and abrasion tester, following two ways: the weight loss and two yarns breakage methods. The average weight loss of a fabric was determined among four specimens (in mg/5,000 cy). Fabric abrasion was done against a standard wool fabric under a 12 KPa pressure. In the two yarns breakage method, the number of abrasion cycles required to break two yarns is determined according to Woolmark Company TM 112 test standard.Findings – In general, no better models to explain abra...

Fabric design considering the optimisation of seam slippage

Purpose – The dependence of seam slippage values on fabric construction parameters makes this property an interesting case for study.Design/methodology/approach – In this study, made on a significant wool and blended fabrics sample, the seam slippage was measured, either in warp direction (weft yarns slip), or in weft direction (warp yarns slip), using a specially equipped load‐elongation tester. Testing was done following the TM 117 Woolmark Company test method.Findings – For most fabrics, the conventional variables that impact seam slippage most seriously are opacity, polyamide content, finish type and cover factor.Research limitations/implications – Since this research does not deal with the variable of yarn crimp in fabrics, it is the cover factor that plays the central role, as the property determining seam slippage. The yarns with lower cover factor (less crimped) are in less danger of slipping between the perpendicular yarns (more crimped) and vice versa.Practical implications – Based on the equati...

Texturing, Stretching and Relaxation Behaviour of Polylactide Multifilament Yarns

Polylactide multifilament yarns were textured in order to be endowed with properties of natural staple fibre yarns for textile applications. Texturing promotes the formation of stable secondary links between the macromolecular chains. A polylactide 167/68 dtex multifilament yarn was textured under different conditions. Relaxation experiments at yield, strain softening, strain hardening and just before breaking were performed. The relaxation behaviour was studied by the application of the generalized Maxwell model. The initial stress induced when stretched, the final non-relaxed stress after relaxation and the stress relaxed at different times were determined. Variations in the relaxation behaviour were related to texturing conditions and stretching.

Lightweight portable sensors for health care

In this article, textile electrodes and semiconductor thin film piezoresistive sensors on plastic substrates were manufactured and fabricated with CMOS processes, respectively. An armband made of plain weave fabric, integrating embroidery textile electrodes of stainless steel (SS) and elastics to conform to human forearms were manufactured. The textile electrodes with an area of 1cm2 were made of two stitching layers for ease of manufacture and electrode robustness and connected through snap fasteners and SS/cotton threads to a signal processing electronic module. Piezoresistive sensors, consisting of n-type hydrogenated nanocrystalline silicon thin films patterned into rectangular bars and having metallic thin leads connecting the sensor to large pads were fabricated on 25µm thick flexible (polyimide) substrates. The textile and thin film piezoresistive sensors were connected to a small lightweight signal processing electronic module of a wireless portable unit for real-time monitoring and recording of the sensors signals. Surface electromyography signals of the forearms of a volunteer wearing the armband with textile electrodes exhibit amplitudes and baseline noise levels comparable to those obtained with standard Ag/AgCl electrodes. The piezoresistive sensor on plastic substrate was stuck with grease to the neck of a volunteer and small front/back neck movement monitored and recorded.

Design and Evaluation of Novel Textile Wearable Systems for the Surveillance of Vital Signals

This article addresses the design, development, and evaluation of T-shirt prototypes that embed novel textile sensors for the capture of cardio and respiratory signals. The sensors are connected through textile interconnects to either an embedded custom-designed data acquisition and transmission unit or to snap fastener terminals for connection to external monitoring devices. The performance of the T-shirt prototype is evaluated in terms of signal-to-noise ratio amplitude and signal interference caused by baseline wander and motion artefacts, through laboratory tests with subjects in standing and walking conditions. Performance tests were also conducted in a hospital environment using a T-shirt prototype connected to a commercial three-channel Holter monitoring device. The textile sensors and interconnects were realized with the assistance of an industrial six-needle digital embroidery tool and their resistance to wear addressed with normalized tests of laundering and abrasion. The performance of these wearable systems is discussed, and pathways and methods for their optimization are highlighted.

Digital printing techniques for denim jeans

This chapter discusses the technological possibilities of using inkjet printing in the development of digital denim. It begins with an overview of current state of the art solutions in digital textile printing and makes a comparison with the traditional techniques of denim colouration, printing and finishing. There follow the essentials of textile printing and colour management, addressing raster image processing issues as well as topics related to image manipulation techniques. Finally, techniques for developing digital denim and some practical applications in clothing design are discussed.

Human body as fashion space: fashion accessories, design and woven fabrics

Purpose – Considering that the human body is undeniable a fashion space, the purpose of this paper is to highlight the importance of design and material choice in the relationship between clothing and accessories, namely, bags, for the fashion consumer. Design/methodology/approach – Initially the paper provides a historical framing of the use of materials in bags and its relation with clothing. Then, are described the characteristics of materials and how the human body relates to them, specifically how the sense of touch plays a decisive role in materials choice. Thus a natural fiber-based fabric as wool fabric is presented as a choice for some brands in the development of fashion accessories. Findings – It was found that there are an immense variety of materials that can be used in bags creation, and the use of them has changed over the years, influenced by social and economic conditions, fashion trends, and by technology evolutions in the production of fibers and composites. Taking in consideration that...

Effect of processing and wearing on viscoelastic modeling of polylactide/wool and polyester/wool woven fabrics subjected to bursting

Polyester fibers (PET) are greatly used in textiles but depend on fossil fuel resources. Poly-(lactic acid) (PLA) is an aliphatic polyester that can be derived from 100% renewable resources. The load–extension plot of a polylactide fiber seems to be especially compatible with that of wool. Consequently polyester/wool 55/45 and polylactide/wool 55/45 yarns were spun using the Sirospun process and plain and twill woven fabrics were industrially produced. Washed and heat set fabrics were subjected to a conventional process of dyeing and decatizing. Fabrics were gradually worn by abrasion using a Martindale wear and abrasion tester. Using the bursting strength test, the viscoelastic behavior of the fabrics when multidirectional extended was simulated and modeled using a modified non-linear Maxwell model. The three steps of fiber decrimping and orientation, fiber stretching and maximum yield and breaking were analyzed. PET/wool fabrics show a more linear behavior than PLA/wool ones and the influence of weave, finishing and wearing on the viscoelastic behavior of PLA/wool fabrics were highly relevant when compared with that on PET/wool ones. It seems that when blended with PET, wool develops its felting effect during finishing and wearing, while when blended with PLA, the felting effect of wool is hardly developed due to the lower resistance of PLA to hydrolysis and its lower thermal stability. PLA fiber properties need to be improved probably through the development of new L-D lactide (PLDLA) copolymers of different ratios between components and molecular weights to reach the optimal desirable properties for the fiber.