Search Results (6)

Large amounts of water, synthetic dyestuffs and chemicals are used in the wet processes of textile finishing, and at the end of these processes, liquors containing chemical substances create a waste load. For this reason, it is of great importance to develop new wet-finishing processes that use less water, dyestuffs and chemicals. For this purpose, the layer-by-layer deposition method (LbL) was used in this research as an environmentally friendly, sustainable method that can be used in wet-finishing processes to minimize chemical, water and energy consumption. The dyeing and functional finishing of cotton fabrics were carried out in one process by the LbL method. Cotton fabrics were pre-treated with a commercial cationic dye fixation agent and cationic charges were produced on the fabric surfaces. Reactive and direct dyestuff groups were used in the dyeing process of cotton fabrics and fluorocarbon was used in the functional finishing process. Eight and 12 dye/fluorocarbon layered structures were obtained by LbL deposition using a laboratory-type padder. Cotton fabrics were dyed and finished with the same dyes and fluorocarbon via the padding method and both samples were compared. The washing, rubbing and light color fastness properties, color strength and color difference of the dyed samples were tested. Tensile strength, air permeability, SEM graphs, contact angle, water and oil repellency analyses were performed for the treated fabrics. Full article

A novel fluorine-containing water-repellent agent (OFAE-SA-BA) was designed and synthesized by emulsion copolymerization, which was used to replace the commercial long fluorocarbon chain water-repellent agent. To improve water repellency, the intermediate and monomer containing two short fluoroalkyl chains were successfully synthesized and characterized by ¹H NMR, ¹³C NMR and FT-IR, respectively. After being treated by the water-repellent agent, the surface chemical composition, molecular weight, thermal stability, surface morphology, wetting behavior, and durability of the modified cotton fabrics were characterized using X-ray photoelectron spectrophotometry (XPS), gel permeation chromatography (GPC), thermal degradation (TG), scanning electron microscopy (SEM), and video-based contact angle goniometry, respectively. The cotton fabric demonstrated water contact angle of 154.1°, both the water and oil repellency rating were grade 4. The durability of water repellency of the treated fabrics only decreased slightly after 30 times, which represented very good washing durability. The finishing agent did not affect the whiteness of the fabric. Full article

Water repellent is an important functional finish for cotton fabric. However, cotton fabrics often have poor washing resistance and other performances after actual finishing. In this study, based on the structural characteristics of cotton fiber and durability of water repellent, a cross-linked amino long-chain alkyl polysiloxane (CAHPS) was first prepared, and then reacted with modified silica. Finally, a chemically bonded organic–inorganic nanohybrid cross-linked polysiloxane (rSiO₂–CAHPS) was fabricated. Furthermore, the rSiO₂–CAHPS was emulsified to obtain a durable fluorine-free water repellent. The water repellent finishing for cotton fabric was carried out by the pad–dry–cure process. After finishing, the cotton fabric had good resistance to conventional liquids and excellent washing resistance, and still maintained good water repellency after 30 rounds of soaping. Moreover, properties including air permeability, mechanical property and whiteness are hardly affected after finishing. SEM and XPS characterization show that a layer of dense silicon film is formed on the surface of cotton fabric by rSiO₂–CAHPS water repellent. The existence of nanosilica can improve the surface roughness of cotton fibers. The synergistic effect of fiber matrix, nanoparticles and CAHPS endows the fabric with a micro/nano-multi-scale micro-rough structure, which improves the water repellency of cotton fabric after water repellent finishing. Full article

Waterborne polyurethane-urea dispersions (WPUD), which are based on 100% bio-based semi-crystalline polyester polyol and isophorone diisocyanate, have been successfully synthesized and doped with single-walled carbon nanotubes (SWCNT) to obtain a finishing agent that provides textiles with multifunctional properties. The chemical structure of WPUD has been characterized by Fourier-transform infrared spectroscopy (FTIR) and nuclear magnetic resonance (NMR). The thermal properties have been evaluated by differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and dynamic mechanical thermal analysis (DMTA). Mechanical properties have been studied by tensile stress–strain analysis. Moreover, the particle size, particle size distribution (PSD), and stability of developed waterborne dispersions have been assessed by dynamic light scattering (DLS), Z-potential, and accelerated aging tests (analytical centrifugation). Subsequently, selected fabrics have been face-coated by the WPUD using knife coating method and their properties have been assessed by measuring water contact angle (WCA), water column, fabric stiffness, and air permeability. The electrical conductivity of textiles coated with SWCNT-doped WPUD has been evaluated by EN 1149 standard. Finally, the surface morphologies of uncoated and coated fabrics have been studied by scanning electron microscopy (SEM). All of the synthesized polyurethane-ureas provide the coated substrates with remarkable water-repellency and water column, being therefore a more sustainable alternative to waterproof coatings based on fluoropolymers, such as PTFE. The additivation of the polymeric matrices with SWCNT has led to textile coatings with excellent electrical conductivity, maintaining water column properties, giving rise to multifunctional coatings that are highly demanded in protective workwear and technical textiles. Full article

External Thermal Insulation Composite Systems (ETICS) are constructive solutions widely used to increase the thermal insulation in new and retrofitted buildings. However, these systems can present several anomalies due to their constant exposure to weathering agents and anthropic factors. Water is generally the major cause of degradation. Thus, the application of water-repellent products can minimize the appearance of anomalies and increase the durability of the systems. In this paper, acrylic-based and siloxane-based hydrophobic products were applied to ETICS, with the aim of assessing the compatibility, effectiveness, and durability of these products. The moisture transport properties and mould susceptibility were assessed through laboratory tests on untreated and treated specimens. The durability of the hydrophobic treatments was also evaluated through artificial aging tests (heat-cold and freeze-thaw cycles). Results show that the protection products generally decreased water absorption, slightly decreased the drying rate, and presented adequate water vapor permeability. After aging, the products still had reasonable effectiveness and, with one exception, improved the water vapor diffusion of the systems. Additionally, ETICS underwent an alteration in the finishing coat (possible modification of the porosity) due to the aging cycles. No clear linear correlation was found between the contact angle values and water absorption results, evidencing the influence of other factors related to the composition of the water-repellent products. Full article

This paper aims to optimize the liquid repellency performance of fluorochemical urethane (FU)—a patented technology with a shorter fluorocarbon chain (C₄). FU is free from persistent bioaccumulative toxins such as perfluorooctanoic acid (PFOA) and perfluorooctanesulfonate (PFOS), unlike the long-chain fluorinated chemicals (>C₆). Different sets of varied finish concentrations with an extender and a wetting agent were prepared to treat the 65/35% polyester/cotton blended fabric. The finish concentration was optimized based on the liquid repellency (water and oil-repellency) of the treated fabric and its laundering durability. In addition, the effect of the finish concentration on selected physical properties of the treated fabric was studied as well. The liquid repellency, laundering durability, and selected physical properties of the treated and untreated fabrics were analyzed using ASTM and AATCC standard test methods. The results of textile substrates treated with 60 g/L of FU show an optimum balance of desired liquid repellency without affecting the physical properties of the fabric significantly. Full article