Journal of Textiles and Polymers
Volume:1 Issue: 2, Spring 2013

This study focuses on the tensile modulus and Poisson’s ratio variations of woven fabric in nonlinear region of load-extension curve. This region of the curve can play as a control approach on the secondary modulus/primary modulus ratio. For this purpose, the fabric modulus and Poisson’s ratio were determined for three different weave structures (plain, 1/3 twill, and 1/7 twill) in the warp and weft directions. The experimental results were analysed statistically to obtain the primary and secondary linear regions and also the nonlinear region of fabrics moduli. The analysis explain that the geometry of fabric structures such as the float and diagonal parts of yarn and also the yarn crimp in both warp and weft yarns have important role on the modulus and Poisson’s ratio of fabrics in the nonlinear region. It was found that the greatest range of the nonlinear region in the warp direction is for plain then, 1/3 and 1/7 twill weaves, respectively, by reason of the increase of diagonal part of yarn and the decrease of float part of yarn in fabric structures, simultaneously. But, due to the buckling of the float part of yarn in the weft direction, the 1/7 twill weave has the greatest range of the nonlinear region and the plain weave has the least one.

In this study, silk yarns were degummed using alkali, enzyme (alcalase) and Seidlitzia Rosmarinus (Kelyab, an Iranian native product) to investigate the effectiveness of products as degumming agents. The efficiency of degumming was assessed in terms of weight loss and tenacity. Some physical properties of the degummed silk yarns, i.e. tensile strength and the yellowness index were also measured. Seidlitzia Rosmarinus (Kelyab) effectively removed sericin leading to maximum 22.73% weight loss. Degumming with alkali and Seidlitzia Rosmarinus (Kelyab) led to the highest weight loss among the samples while the strength of the yarn decreased with severity of the degumming treatments. Seidlitzia Rosmarinus (Kelyab) decreased the strength of the yarns at higher concentration and treatment time. The SEM micrograph showed that the SeidlitziaRosmarinus (Kelyab) in the highest concentration could completely remove the sericin while no serious damage was observed.

According to the literature, it is possible to replace synthetic dyes with more echo-friendly natural dyes. One of the popular natural dyes in Iran is madder. This paper reports the effect of age and type of madder in natural dyeing process for better color behavior prediction. Effects of 4 different types of madder along with the role of the concentration and pH of dye bath are investigated. The amount of dye absorption is also evaluated by calculation of K/S value in the wavelength of minimum reflection. Samples are treated by using the classical aftertreatment process for natural dyes and the effect of aftertreatment on light and washing fastnesses of samples are reported. The CIELAB colorimetric specifications of samples are measured under D65 illuminant and 1964 standard observer. The light and washing fastnesses of dyed samples are also reported. Finally, the chemical structures of employed madders are studied by FTIR technique.

The growing need for materials suitable for sustainable development and improved healthcare has motivated scientists and engineers worldwide to investigate biopolymers. Success in this direction hinges on our ability to tailor properties of biopolymers and find cost effective processing methods.Authors applied a versatile nanofiber production technique known as electrospinning to process a variety of nanoassemblies with high specific volume and porosity from biocompatible, biodegradable and nontoxic natural biopolymers. These nanofibers and nanowebs with tailored physical, chemical, biological and mechanical properties are attractive for designing ecologically friendly products in a range of applications from personal care to healthcare such as hospital apparel, drug delivery systems, and scaffolds for tissue engineering and tissue regeneration.The present study reports on electrospinning of natural biopolymers chitosan and alginate and their blends with other biocompatible polymers. Several solvent systems and different processing conditions are investigated for effective electrospinning of biopolymers. Optimum processing conditions for producing desired electrospun nanowebs are discussed.

The aim of this study was to apply experimental design in determining the order of magnitude as well as the intersectional interactions between various parameters affecting the microstructure of fabricated polyethylene membranes via thermally induced phase separation method. In this study, among various parameters, the polymer concentration, cooling bath temperature and film thickness were selected as the most effective variables on the structure of membranes. The analysis variance results showed polymer concentration and cooling bath temperature were identically significant. Film thickness effect, however, showed less importance than other parameters. Surface response plots showed that lower polymer concentration and film thickness and higher cooling bath temperature would result in higher porosity. The results of analysis of variance showed that the interactions among individual parameters are significant. However, with an increase in the cooling bath temperature and polymer concentration, the effect of film thickness on the porosity would be negligible.

Random-velour needling technology is a modified version of conventional needling process. Properties of the random-velour needled fabric are controlled by the structural alteration that occurs during random-velour needling, is due to re-orientation of fibers within the pre-consolidated fibrous assembly by special fork needles. This interaction results in creation of a dual structure, comprising base and pile layers. In this work the effect of needling parameters and fiber characteristics on force exerted on the fork needle was investigated. The effect of principal parameters on total average force «Frms» exerted on individual fork needle was determined using an Artificial Neural Network (ANN) modeling and the error percentage of absolute average of predicted tests data was also calculated. Significance percentages of input parameters on «Frms» was indicative of the similar influence of fiber characteristics and needling parameters on «Frms». Results manifested the importance of punch density and barbed needle penetration depth during initial consolidating needle-felting operation. Result of the neural network assessment testified that the network in general was capable of mapping input and output parameters.

Thecolorimetric specifications and the dimensional properties of the spectral reflectance of natural dyes, which are used in the traditional handmade Persian carpet, are investigated. Different natural dyes are employed on woolen yarns to provide a collection of 286 colored samples. The colorimetric expansion and the spectral behaviors of samples are compared with Munsell color-matt finish collection.The principal component analysis technique as well as the non-negative matrix factorization method is employed for the spectral evaluation of datasets. Although the natural dyes present smaller color gamut in comparison to the Munsell dataset, the dimensional properties of the reflectance spectra of both datasets provide very close cumulative percentage of variances. The results are reconfirmed by the calculation of the mean root square errors between the original and the reconstructed spectra of samples from reduced spaces employing different numbers of positive-negative and all positive bases as well as the CIELAB color difference values under D65 and A illuminants and 1964 standard observer.