La menace d’une pandémie mondiale (du type H1N1) amène nos sociétés à se protéger des microorganismes infectieux. Différentes solutions permettent de se protéger de ces microorganismes. En dehors de la vaccination et autres prophylaxies, il existe des moyens de protection individuelle ou collective qui consistent à filtrer l’air respiré pour en extraire les aérosols infectieux. L’objet de cette thèse a consisté à élaborer une structure textile filtrante pourvue de propriétés biocides. Dans un premier temps, le textile a été fonctionnalisé par la cyclodextrine, molécule cage connue pour ses propriétés complexantes vis-à-vis de molécules variées. Les paramètres de l’ennoblissement du textile par la cyclodextrine ont été optimisés afin de ne pas dégrader le support. Des tests biologiques ont mis en évidence une bonne cytocompatibilité du textile modifié. Les textiles ont ensuite été activés par imprégnation par des agents biocides. Des essais de cinétiques de libération ont montré que les biocides étaient solidement fixés sur le support. Des tests de microbiologie ont révélé leur bonne biodisponibilité par le biais d’une réduction remarquable de l’adhésion bactérienne. Enfin, l’étude a été complétée par des tests de filtration d’aérosols standards, qui ont montré que la modification des fibres ne perturbait pas les propriétés filtrantes du textile. Ainsi nous avons réussi conférer des propriétés anti-infectieuses à une structure textile sans détériorer ses performances de filtration. / The threat of a worldwide pandemic (like H1N1) leads occidental societies to develop protections against infectious microorganisms. Defenses against microorganisms can be organized around some solutions. Apart from vaccination or other prophylaxis, individual or collective protections consist in the filtration of the air in order to remove infectious particles. The aim of this thesis consisted of working out a textile structure capable of biocidal properties. First, textile has been functionalized by cyclodextrin. Cyclodextrins are host molecules which have the capability to make inclusions (or host–guest) complexes with a wide range of molecules. Parameters of the curing were improved in order to minimize the textile structure spoiling. Biological tests have proved the good cytocompatibility of the modified textile. Then textiles have been activated with biocidal molecules. Kinetics of release have shown that biocides were durably fixed on the textile and microbiological tests have demonstrated their bioavailability through a striking reduction of the bacterial adhesion. Finally, this study was completed by mechanical and filtration tests which have revealed that fibers modification did not disturb filtration properties of textile. Finally, we succeeded in offering biocidal properties to a textile structure without affecting its filtration performances.

This thesis concerns the development of a robotic cell to perform assembly and handling operations on cloth.- A flexible automation approach was adopted, in which the robot was required to control the cloth panel during both handling and sewing operations, without the aid of hard automation attachments which might limit the flexibility of the system. The cell consisted of an adaptively controlled robot, a hierarchy of controllers, a conventional sewing machine, a two-fingered fabric steering end-effector, and several sensor systems. A technique was developed for producing a seam parallel to an edge of arbitrary contour, in which two cameras, a cloth tension sensor and the sewing machine's shaft encoder provided the sensory input. Two sensory servo control systems were required, one control system generated the robot's trajectory to maintain a small constant cloth tension, and the other directed the robot to manipulate the cloth panel to maintain a constant seam width. The design of the cloth tension control was based on the measured frequency response of the open loop system. The seam width control was designed using simulation studies, which accounted for the control transfer function, and nonlinearities such as camera pixel resolution, time delays and robot motion limitations. Several robotic handling techniques were developed, so that a cloth panel placed arbitrarily on the sewing table could be set up for an edge seaming operation, and the cloth could be rotated about the needle. The system's flexibility was demonstrated in the assembly of an irregularly shaped cloth panel, in which three adjacent sides were sewn up.

This thesis is concerned with the influence of the merchant converter on design practice in the Lancashire cotton industry in the period 1900-1939. The thesis aims to supplement the existing design histories of the industry by focusing, firstly, upon the role of design in the context of the industrial and commercial organisation of the industry, and secondly, by examining the practice of design in relation to the export trade in cotton goods. The Lancashire cotton industry had a unique structure that facilitated the production of a wide variety of cotton piece goods that serviced the needs of consumers in markets across the globe. Despite the enormous decline of the inter-war years, in which the major markets of China and India were dramatically reduced, the industry was able to maintain a significant export trade in cotton piece goods. The successful sale of these goods depended in part upon the successful interpretation of consumer preferences by their designers. Lancashire employed a large number of designers who worked either in the employ of manufacturers or on a freelance basis. The thesis examines the different categories of designer who supplied designs to the Lancashire industry, including their education and working practices. It also investigates the relationship between the designer and the agents who employed them. Lancashire's ability to respond appropriately to consumer demands played a significant part in establishing and maintaining exports to markets such as West Africa. A case study of the West African market illustrates the mechanisms that made this response possible. It also emphasises the importance of established merchant organisations that provided the links between consumer, manufacturer and designer. The case study underlines the key relationship between the communication of market information and the production of commercially successful designs. The thesis also addresses the issue of government intervention into an industry that was faced with increasing economic hardship as a result of the loss of markets worldwide. Design was not at the forefront of government policy in respect to the Lancashire cotton industry. Nonetheless, design issues were increasingly associated with government attempts to improve the trade in manufactured goods during the inter-war period, and this is particularly evident in the activities of the Board of Trade. The thesis evaluates the activities of two government organisations, the Council for Art and Industry and the Department of Overseas Trade, their reception by merchants and manufacturers of the day, and assesses the strengths and weaknesses of the contribution they made to the industry.

Cotton possesses many characteristics that make it desirable to the consumer, and this has resulted in its usage in a broad range of products. Cotton, however, is a flammable material that is easily ignited and rapidly consumed. The flame retardant treatment of cotton is, therefore, an important textile process that has received wide attention over many years. There are a number of commercial flame retardant treatments available for cotton, the most common being phosphate-based. These treatments, however, often have drawbacks or have a negative impact on the desirable properties of the fibre and the challenge still exists for designing better flame retardant products and systems that are durable and have limited impact on fibre properties. The study considers the application of the sol-gel as a coating on fabric that was pre-treated with a phosphate-based flame retardant or as a means for applying a phosphate-based flame retardant. Both treatment methods were found to be suitable for imparting flame resistance to the fabric. The effect of various phosphate-based flame retardants on flammability and fabric properties such as colour, handle and strength was investigated and it was shown that a diammonium phosphate and urea combination gave the best flame resistance. In this regard, a flame resistance was achieved with a lower amount of phosphorous than was used in similar conventional treatments. The durability of the coating to rinsing with water and soaping with a detergent was also investigated. It was found that the flame resistance was lost after rinsing or soaping but the prevention of afterglow combustion was retained. It was shown that the preparatory treatment of the fabric influenced the sol-gel coating process and the flammability of the fabric. Mercerisation and bleaching of the fabric increased the “wet pick-up” during the coating process and improved the flame resistance. The influence of various factors was also investigated in further detail. The ratio of the sol-gel components, the delay after coating prior to drying (hang time) and the curing time were investigated using an experimental design. The curing time and the ratio of components in the sol-gel were shown to have the greatest influence on fabric properties and fabric flammability. It was shown that there is a trade-off between the desired high level of fabric flame resistance and preserving the inherent properties of the fabric such as colour, handle and strength.

Hydroentanglement is an important technique of bonding fibres to produce nonwovens using high velocity waterjets as the primary bonding tool. The work reported in this thesis addresses the gap in scientific knowledge and understanding, both theoretical and experimental, related to the impact forces and energy of the waterjets used in the hydroentanglement process. The current study focused on the impact forces and energy involved in, and the optimisation of, the hydroentanglement process. The results of the experimentally measured waterjet impact forces have been used to characterise the waterjets as well as to verify empirically the theoretical models currently available for explaining the mechanics of the hydroentanglement process. Since the process of supplying pressurised waterjets consumes a great deal of energy, the study of energy consumption and efficiency of the system has been critical. A method was proposed and used to determine the coefficients of velocity and water discharge of an industrial machine set-up, helping explain the mechanism of energy transfer during hydroentanglement and to concurrently optimise the process. Furthermore, a response surface experimental design was used to optimise the hydroentanglement of viscose and Polylactic acid (PLA) fibres into nonwovens. The selected Box-Behnken design, with four factors, namely the waterjet force, machine processing speed, input weight and fibre type, was employed to investigate the multivariate process factors and their interactive effects on physical and mechanical properties of nonwovens. Two sets of experiments, the later for validation, were performed to study the energy transfer efficiency. The results of the relative energy transfer to bond the fibrous web showed that it was possible to produce nonwovens using lower input energy without compromising the quality of the products. The optimum waterjet pressure and machine speed used to produce the Abstract nonwoven with the highest tensile strength for the least amount of energy supplied were identified.

Forced vibrational experiments and stress relaxation experiments have been performed on acetate rayon, viscose rayon, nylon, and polyethylene over a range of humidities at both 2°C and 25°C. Forced vibrational experiments have also been carried out on acetate rayon, viscose rayon, and raw silk over the temperature range -80°C to 0°C. Interpretation of previous experiments is discussed in terms of both Newtonian viscosity and Eyring viscosity. The apparatus employed is described and a method for calibrating the solenoid of the forced vibrator is outlined. An inverse relation has been found between ηω and the negative slope of the stress relaxation curve, E°. Since the equation ηω = π/(4.606) E° derived on the basis of Newtonian viscous units predicts a direct relation between ηω and the slope E°, it is assumed that the flow in stress relaxation must be non-Newtonian* Preliminary calculations indicate that a more satisfactory relation between ηω and E° may exist if the flow units involved in stress relaxation follow the Eyring law of viscous flow. An outline for determining such a relation is given. The experimental 1y observed increase with decreasing temperature of dynamic modulus, stress relaxation modulus, and energy loss, as measured by ηω, is interpreted in terms of increasing order of chain segments. A maximum found at -55°C in the ηω vs. temperature curve for viscose rayon is attributed to a "freezing in" of segment motions as the result of a second order transition. / Science, Faculty of / Chemistry, Department of / Graduate

This dissertation presents an investigation on the long-term behavior and the structure-property relation in high performance polymeric fibers. These fibers have wide applications in structural cable and ropes and reinforced composites. Therefore, the understanding of their structure-property relation and their behavior under external mechanical stress is very important. The fatigue and creep behavior were studied. A general lifetime equation was derived to correlate the material lifetime with the applied stress level. The failure criterion of “critical strain” was identified. The failure mechanism was shown to be a deformation route. The fatigue lifetime was predicted from known material constants. Several material parameters were defined to characterize the fatigue and creep properties. The fatigue property is characterized by the fatigue strength and fatigue strength index; while the creep property is characterized by the creep strength and creep strength index. The fatigue strength index was used to show that fiber with a rigid chain structure, such as Kevlar®, Techanora ® and Vectran®, generally have better fatigue resistance than a flexible chain fiber, such as Spectra®. Twisting was found to influence yarn properties. A model based on composite theory was developed to predict the change in the yarn modulus with the degree of twist. The desire for nondestructive prediction of the residual lifetime of a used material initiated the efforts to find a signature of the stress and thermal history in Kevlar® fibers. To achieve this, a new testing methodology has been developed. An iso-strain force-temperature test (IFTT) was shown to yield quantitative information on the stress and thermal history as well as the information of relaxation and transitions in many materials. The IFTT behavior of a Kevlar® fiber maps well with its structure examined by X-ray diffraction. The IFTT was also used to screen the processing for property enhancement via post-treatment. Different post-treatment routes have been investigated for Kevlar ® fiber. Tension, heat, hydrostatic pressure, and different media of water, mercury and silicon oil have been utilized to alter the materials. The evolution of its property and structure have been carefully examined. It is shown that the modulus of PPTA is determined by two structure parameters: misorientation and a paracrystalline parameter.

The objective of this thesis is twofold - (1) to design the unit processes for treating the waste from a specific industrial plant using the best practicable technology, and (2) to critically examine the theory of these unit processes for utilization in design. The industrial waste was derived from a synthetic button and textile trimmings factory producing polyester and casein buttons. The effluent has a high pH and COD; contains metallic poisons; and is highly coloured. It exceeds the limitations for effluent quality promulgated by the Cape Town Municipality before discharge to the sewers. A certain measure of pretreatment before discharge to the sewers was therefore required. The treatment process eventually selected consists of neutralization; flocculation; sedimentation; sand filtration of the sludge; and atmospheric drying of the sludge.

El texto completo de este trabajo no está disponible en el Repositorio Académico UPC por restricciones de la casa editorial donde ha sido publicado. / No presente resumen.

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