Ascensión Riva

Objective measure of woven fabric’s cover factor by image processing

Digital image processing techniques have been applied to perform an automatic method for the objective measure of woven fabric’s cover factor. Based on a frequency domain analysis, digital images of woven fabric samples, obtained with a camera assembled to a microscope, were cropped to enclose the maximum integer number of warp and weft periods and leveled for non-uniform illumination. Posterior thresholding, designed to perform satisfactorily for both high and low cover factor fabric samples, gave rise to the objective value. The method was applied to three different sets of samples manufactured in plain weave, with known yarn numbers and thread counts. Cover factors obtained by this method showed good correlation with those obtained by a set of visual observers and were consistent with woven fabric parameters: yarn numbers (tex) and thread counts (yarns/cm). The procedure could be useful to monitor mean cover factor as well as cover factor variability in fabric batches. It does not require sophisticated equipment and could be straightforwardly implemented in a textile analysis laboratory.

Modelization of the Influence of the Wearing Conditions of the Garments on the Ultraviolet Protection Factor

The aim of the paper was the modelization of the influence on the Ultraviolet Protection Factor (UPF) of the more representative properties of the wearing conditions of the garments, the tension produced in contact with the body and the wetness. The study was carried out on undyed woven fabrics manufactured with three different cellulosic fibers (Cotton, Modal and Modal Sun) and with three different structures. The transmission of Ultraviolet Radiation (UVR) in the whole ultraviolet range, as well as in the UVA and UVB regions, was measured and the UPF was determined. A statistical model for each fiber type was formulated, which allowed the prediction of the UPF according to the UPF of the original fabric (unstretched and dry), the tension and the wetness.

Action of a finishing product in the improvement of the ultraviolet protection provided by modal and modal sun fabrics: Modelisation of the effect

The ultraviolet protection factor of a fabric is a quantitative measurement of the effectiveness of the fabric to protect the human skin against ultraviolet radiation. The protection provided by uncoloured cellulosic fabrics is, in general, too low, but can be improved by the finishing treatment with UV-absorbers. In the present paper Modal and Modal Sun fabrics with different compactness, and hence with different initial Ultraviolet Protection Factor values, are treated with several concentrations of an UV-absorber, according to a predefined experimental plan. The influence of each variable as well as their interaction on the response ultraviolet protection factor is analysed and a statistical model for predictions is proposed.

Enzymatic Finishing of Wool Fabrics: Effects of Different Treatments with a Protease on Physical and Chemical Parameters of the Fabric

SUMMARY The objective of the present work is to evaluate the action of a protease when applied on a high quality wool fabric to obtain an improved touch and drape on the fabric as well as to decrease its shrinkage and pilling propensity. The effectiveness of the enzymatic treatment as well as the intensity of the attack to the wool fibre are evaluated by determining several mechanical and chemical parameters.

Relationship between microstructure and properties of false-twist textured and stabilized polylactide. Part 2: physicochemical characterization, accessibility of the amorphous phase and dyeing behavior

Polylactide fibers (PLA), textured by false twist at different temperatures (135, 150 and 165℃) and draw ratios (1.30, 1.35 and 1.40) were stabilized by the application of a continuous thermal treatment at 100℃ and 50 m/min. The effect of thermal stabilization on the microstructure was determined by physicochemical tests such as iodine sorption or differential solubility. Iodine sorption and differential solubility are closely related to the crystallinity of the samples. Stabilization enhances crystallinity and orientation with the result that differences between the samples are diminished. Color value differences, albeit reduced, in some cases exceed the accepted limits. Color absorption is mainly dependent on the orientation and accessibility of the amorphous phase.