Faouzi Sakli

Ultrasonic preparation of cationic cotton and its application in ultrasonic natural dyeing

Cationization of cotton fabric was conferred by the sonicator reaction of cellulose with bromoacetyl bromide, followed by substitution of the terminal bromo groups by triethylamine. Experiments showed that the optimal volume of bromoacetyl bromide necessary to succeed the first stage was 0.4 mL. The order of weight gain for various processes indicates, ultrasound, 25 kHz> ultrasound, 40 kHz> mechanical stirring. Also, for the second stage the order of nitrogen contents indicates ultrasound, 25 kHz> ultrasound, 40 kHz> mechanical stirring. The structures of both untreated and cationic fibres were investigated by FTIR spectroscopy. Modified cotton fabric was subsequently dyed in both conventional and ultrasonic techniques with isosalipurposide dye isolated from Acacia cyanophylla yellow flowers. The effect of dye bath pH, ultrasonic power and frequency, dyeing time and temperature were studied and the order of K/S values indicates ultrasound, 25 kHz > ultrasound, 40 kHz > CH. ultrasound was also found to enhance the dye uptake and the overall fastness properties. Analysis of the sorption isotherms of isosalipurposide dye on cationic cotton fabric shows that the Languimir isotherm equation is best able to correlate the data.

Evaluation of wet pneumatically spliced elastic denim yarns with fuzzy theory

This paper focuses on the evaluation of wet pneumatic spliced elastic yarn performance using the fuzzy logic theory. Referring to Altinozs study (Altinoz & Winchester, 2001), fuzzy logic method allows a new level of flexibility over traditional mathematical methods in defining and evaluating constraints. The application of fuzzy rules and fuzzy memberships is discussed and investigated. Using the suitable parameters and optimized splicing conditions such as yarn count, length of splice and duration of water joining, the results show that triangular membership gives better fitting of experimental results. Compared to the experimental properties, theoretical performances of the wet splice can be predicted in the desired field of interest. Our results also indicate that the splice performance remains influenced especially by the elastic yarn count and the splice length as well. In this work, the experts opinions using our fuzzy logic model were formalized with precision. Compared with regression model, the fuzzy model gives a more accurate prediction than the regression model.

Morphological Characterization of Individual Fiber of Agave americana L.

The fine structure of Agave americana L. fiber was studied using scanning electron microscopy (SEM) analysis. The individual fibers have a helical structure whose axis can be considered as parallel to the main axis of the bundles of ultimate fibers. Individual fibers are extracted from the technical one with the help of a 3.8% NaOH alkali solution at 130°C. SEM analysis of an individual fiber, using image analysis software, shows that the shape of an individual fiber can be likened to a ribbon with a main transverse dimension around 3.1 μm which can be considered as very small in comparison with other individual natural fibers. The SEM analysis has also shown the fiber to have a helical structure composed of square-shape spirals which were also examined. In this study, an attempt is made to explain some of the physical and mechanical properties of the bundles of ultimate fibers, such as its high strain (49%) and its low density (1.36), through the morphological characterization of individual Agave fibers.

Physico-chemical characterisation and tensile mechanical properties of Agave americanaL. fibres

In this paper, the physico-chemical and mechanical properties of Agave americana L. fibre are studied to explore the possibilities of using this fibre in textile industry. Three different processings for extracting fibres from the leaf of Agave americana L. plant were investigated: (i) raw fibres manually extracted, (ii) fibres extracted by retting leaves in seawater and (iii) fibres extracted after hydrolysis treatment of the leaves in distilled water. Chemical composition (cellulose, lignin and hemicellulose contents), physical properties (density, fineness and crystallinity) as well as mechanical properties of the resultant fibres were measured. The chemical composition reveals that the Agave americana L. fibre has a cellulose content at the order of 62% which is similar to that of other lignocellulosic fibres. The distilled water extracted fibres developed the highest cellulose content. Lignin content of Agave americana L. fibre is low compared to other natural fibres (2.4%) and seawater-extracted fibres generated the lowest lignin content (2.12%). Fourier transform infrared spectra (FTIR) and x-ray diffractometry of all extracted fibres revealed the same chain conformation. X-ray diffractograms showed that cellulose I is the main crystalline constituent. Concerning physical and mechanical properties, raw fibres were characterised by the lowest density (0.9) and the highest crystallinity (51.2%), they are also stronger and less extensible than the other two fibres. In this paper, we attempt to study the effect of extraction in water on the mechanical and physical properties of Agave americana L. fibres.

Prediction of fabric drape using the FAST system

Abstract In this study, we investigated the relationship between the fabric drape coefficient from the drape meter and mechanical properties tested on the fabric assurance by simple testing system (FAST). Different kinds of woven fabrics with two kinds of weave (plain and twill) were tested. Three regression models are proposed for each type of weave and for all fabrics using the multiple linear regressions. The regression results were analyzed in terms of correlation coefficients, T and p-values. A neural model is proposed using the neural networks and it is compared to the regression one.

Physico-chemical and mechanical characterization of alkali-treated Agave americana L. fiber

This study investigates the effect of mercerization on the physico-chemical and mechanical properties of Agave americana L. fiber. The alkali concentration is a crucial parameter which affects the crystallinity and the tenacity of the fiber. Treatments with low alkali concentrations produce fibers that are stronger than the untreated fibers and at this level the crystallinity reaches high values. However, treatments with high concentrations (>2% wt/v) result in weaker fibers with low crystallinity index. The chemical composition of A. americana L. fibers is also altered by the mercerization process insofar as the cellulose content increased with the NaOH concentration while the hemicelluloses and lignin contents decreased.

Contribution to the optimisation of artificial ligament mechanical properties

Abstract In this work, artificial anterior cruciate ligaments were manufactured using braiding process. The mechanical behaviour of circular braids under tensile loads was studied. These braids were manufactured from different yarns and materials. A study of the effect of yarns characteristics and the machine parameters on the braid mechanical properties was done. Predictive models of the braid mechanical response based on the constituent yarn characteristics and the machine parameters have been developed. The last part of this study has been devoted to optimise the braid mechanical properties to be close to those of native ligament.

Evaluation of physical and mechanical properties of Tunisian camel hair

Abstract The evaluation of the textile potential of the camel (Camelus dromedarius) underhair is a field of investigation that has been approached only a few times, as indicated by the low number of articles in literature. This is most probably due to the scarcity of this fibre and the problems with the dehairing process of unsorted fibres of dromedary. Aiming at a better economic exploitation of the quantity of fibrous matter in the fleece of Tunisian dromedary, a project of valorization of these fibres was launched. The objective of this study was to analyze the physical and mechanical properties of dromedary hair. Results indicate that it has exceptional textile potential. Also, the factors age and area have a significant effect on all parameters of control (fibre diameter, fibre length, tenacity, and strain), and the interaction between these two factors is not negligible. So simplified models, based on the analysis of variance, define the selection procedure of these fibres according to various factors of control taken into account and preserved in those models.

Optimization and Characterization of Pulp Extracted from the Agave Americana L. Fibers

The influence of temperature, pulping time and soda concentration on the yield, kappa index, brightness and fiber density of Agave Americana L. pulp has been studied. Using a factorial design to identify the optimum operating conditions, equations relating the dependent variables to the operational variables of the pulping process were established. The morphology of the cellulose fibers (length distribution, diameter distribution and crystalline index), obtained from the optimum pulping already determined by the statistical study, was determined by measuring 5020 fibers with optical microscopy equipped with CCD camera and image analysis software, and FT-IR spectra. Cellulose fibers extracted from Agave Americana L. had a lower lignin content value (1.13%) and an absorption capacity of 10.5 g/g. Finally, the characteristics of the optimum Agave pulp were compared to those of other vegetable fibers.

Optimization of textile parameters of plain woven vascular prostheses

This paper investigates and reports the effect of some textile parameters (yarn and fabric parameters) on the main performances of plain woven vascular prostheses in order to enhance their overall quality. We weaved tubular structures with different fabric densities using texturized Dacron® polyester filament yarns with different linear densities and filament counts, in warp and weft directions. The performances of the manufactured samples, such as wall porosity, water permeability and mechanical features, have been tested. By adopting a two‐level fractional factorial design of experiments, the responses were fitted to predictive models using a multiple linear regression method. The models were tested by variance analysis and validated by correlation between measured and predicted values. We determined the optimum settings of main textile parameters enhancing plain woven vascular prosthesis quality by contour plots method.