2,277 research outputs found
Sol-gel synthesis and hybrid thin film deposition for innovative textile finishing. Study, characterization and environmental impact evaluation
Get PDFThe aim of the present work was to study and characterize a new approach to finish textile fabrics. This new approach is based on the production of a thin film on textile surface containing metal-organic precursors. Organic-inorganic hybrid thin films based on silica or titania sols were thus developed by sol-gel process for flame retardant, hydro-repellent and self cleaning fabrics. The proposed hybrid compounds for textile finishing are expected to help the development of new finishes, constituting a valid alternative to the well established commercially available treatments of textile. In fact, traditional treatments could have several disadvantages: they could be hazardous materials for the workers during production and application, and for end-users who wears the treated cloths. Moreover, they are responsible for water pollution and for high energy consumption.
Halogen free flame retardants hybrid films were realized to enhance the thermal and fire stability of cotton. To this aim specific combination of silica precursor (3-aminopropyltriethoxysilane (APTES) and diethylphosphatoethyltriethoxysilane (DPTES)), phosphorus donors (diethylphosphite (DEP) and DPTES) and nitrogen donors (APTES and melamine-based resin (MF)) were tested.
Free fluorocarbon water repellent hybrid films were then realized onto cotton and PES fabrics using octyl triethoxysilane (OTES) as precursor and MF as cross-linker. Three different MF concentrations and four MF:OTES molar ratios were evaluated.
The self cleaning study was finally developed following two main research approaches. In the first one, stable aqueous titania sols were synthesized at suitable pH for the industrial application without the addition of alcohols, glycol or acetyl acetone. In the second one, TiO2 thin film coatings were realized on cotton fabrics by sol-gel technique. The effect of different starting acidic solutions (nitric, hydrochloric and acetic acids) and the addition of polyethylene glycol (PEG) onto two different TiO2 concentrations were investigated
Photocatalytic properties and optical characterization of cotton fabric coated via sol-gel with non-crystalline TiO2 modified with poly(ethylene glycol)
No full textTiO2 thin film coatings were realized on cotton fabrics by sol–gel technique using titaniumiso-propoxide. The effect of different starting acidic solutions (nitric, hydrochloric and acetic acids) and the addition of poly(ethylene glycol) onto two different (0.25 M and 0.025 M) concentrations of TiO2 have been widely investigated. The applications of the sol were performed by pad-dry-curingmethod at 120 °C for 5 min for curing condition. The microstructural, morphological and optical properties and the photocatalytic activity of the films were investigated. In particular, XRD analysis showed a thin film deposition without any crystalline structure, which was also confirmed by Tauc plot analysis with a band gap from3.3 to 3.5 eV. The photocatalytic activity assessment, evaluated by degradation of Procion red PX4B dyestuff, was carried out by visible and UV (365 nm) sources. Under ultraviolet exposure condition the rate of degradation of pure TiO2 films shows an interesting linear correlation with pKa of the acids used. Moreover, the PEG addition into mineral sol–gel solution dramatically increases the rate of dye degradation under exposure. Nevertheless, no significant changes in the mechanical properties were observed after 100 h of UV and visible exposures
Properties of SiOxCyHz thin film prepared by plasma enhanced CVD on different textile fabrics
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Plasma enhanced CVD of SiOxCyHz thin film on different textile fabrics: influence of exposure time on the abrasion resistance and mechanical properties
No full textIn order to improve textile fabric abrasion resistance, in this work a SiOxCyHz thin film was realized by low pressure plasma chemical vapour deposition (PCVD) at room temperature, using hexamethyldisiloxane (HMDSO) as precursor compound. To test changes in the performance properties of the surface finished samples as a function of the type of the substrate, the deposition was carried out on different textile fabrics. The polymerization processeswere followed by weight measurements of textile fabrics. It was found that, after PCVD, a significantly lower fabric weight loss was observed on treated samples after rubbing than on the untreated samples. The morphology, elemental composition and type of chemical bonding present in the film applied on textile fabrics were also investigated using electron scanning microscopy (SEM), energy dispersive X-ray (EDX) and infrared spectroscopy techniques (FT-IR (ATR)). The results showed a substantial enhancement of wear resistance for the surfaces modified with the presented process, while tensile and tearing strength were adversely affected
Electrokinetik Phenomena of 3-Aminopropyltriethoxysilane-Based Cotton Finishing
No full textThe textiles are characterized by their inner and outer structure and functional groups. Specific adsorption of ions or dissociation of the surface groups in aqueous solution result in their surface charge. Changing the number of functional fiber surface groups, e.g. by blocking in dyeing and finishing processes, and their dissociation affect the distribution of surface charge, as well as the thickness and distribution of the electric double layer which results in different fabric electrokinetic phenomena [1-4]. Immersed in water (pH 6.5-7.0) cotton fibers, like most textile fibers, are negatively charged in neutral and alkali aqueous solutions [5]. Therefore, the adsorption of textile auxiliaries, dyestuffs, optical brighteners and finishing agents is difficult due to repulsive forces. Cationisation, as an alternative method for improving dyestuff and surfactant adsorption, increases cotton zeta potential and changes the fiber surface charge [3, 4, 6-10]. Hashem et al. among others, studied the parameters of application of a non-polymeric cationic agent such as epihalohydrin; 2,3-epoxypropyl trimethyl ammonium chloride (EPTAC) and 3-chloro-2-hydroxy-propyl trimethyl ammonium chloride (CHPTAC) by pad-roll and exhaustion methods, but as after-treatment only [8, 10]. On the other hand, Grancaric, Tarbuk et al. [3,4] introduced cationisation during mercerization processes, which resulted in new material. Recently, some commercial products for the same purpose have been developed.
In the last years, the sol-gel technique has remarkably proved its exceptional potential regarding the functionalization of textile fabrics. Sol-gel solution leads to the formation of completely inorganic or hybrid (organic-inorganic) coatings that can be used to confer functional properties, such as antimicrobial, water repellency and flame retardancy [11]. In this study 3-Aminopropyltriethoxysilane (APTES) has been selected for the cationisation of cellulose due to the presence of amine groups into polysilane network
Sol-gel derived architectures for enhancing cotton flame retardancy: effect of pure and phosphorus-doped silica phases
No full textPure and phosphorus-doped silica phases derived from sol–gel processes have been investigated, aiming to assess any enhancement of the thermal and fire stability of cotton fabrics. Indeed, it has already been shown that the combustion behaviour of cellulosic substrates can be strongly affected by the presence of a protective phosphorus-rich silica coating. Thus, in the present work, the performances of coatings consisting of pure silica and phosphorus-doped silica have been investigated and compared by using thermogravimetry and combustion tests (more specifically, resistance to an irradiative heat flux and to a flame application). The results show that the thermal and thermo-oxidative stability of cotton, as well its resistance to an irradiative heat flux of 35 kW/m2, have been enhanced by the deposited coating, irrespective of the presence of phosphorus. However, the best results have been achieved exploiting the joint effect of thermal shielding (exerted by the silica phase) and char-forming (as a consequence of the phosphoric acid source present in the alkoxysilane precursor). On the other hand, only pure silica coatings, despite their very low add-on, have proven to protect cotton from the application of a methane flame for 5 s, favouring the formation of a thermally stable residue
Phosphorus- and nitrogen-doped silica coatings for enhancing the flame retardancy of cotton: Synergisms or additive effects?
No full textIn the present work, the synergistic or additive effects due to the concurrent presence of phosphorus- and/or nitrogen-based compounds on the flame retardancy of cotton fabrics previously treated by sol-gel processes have been thoroughly investigated. Indeed, although additives containing P and/or N structures have been exploited for imparting fire resistance to cellulosic substrates, the quantification of their synergistic level has not been fully considered. More specifically, the concept of “synergistic effectiveness” has been applied to cotton fabrics treated with a phosphorus-doped silica coating, further doped with a bisphosphonate, melamine or urea. Flammability and cone calorimetry tests have shown that only phosphorus (i.e. bisphosphonate) is able to promote a certain synergism with the solegel derived oxide phases in terms of residue, heat release rate and total burning time
Effect of Nanoparticle Finishing onto Color Matching of Textile Fabrics
No full textChemical finishing procedures are widely used to improve the properties of natural and synthetic fibers and fabrics. For this purpose, textile materials are treated with different functional finishes, such as repellent, durable press, soil-release, flame retardant, antistatic, and antimicrobial. Water repellent finishing on fabrics is mostly imparted by the incorporation of low surface energy compounds, accompanied by the increase of the contact angle of liquids on its surface. Recent approaches are based on the use of nanoparticles such as highly branched 3D surface functional macromolecules called dendrimers to enhance water repellency. In this study the effect of particle size on surface roughness and color assessment after treatment of cotton/polyester fabrics were evaluated. For this purpose, three types of commercially available reagents (dendrimer water repellent, fluorocarbon included dendrimer water-oil repellent and fluorocarbon water-oil repellent) were compared, for two kinds of disperse dyes. Moreover, water and oil repellency performances were measured as well as mechanical properties. Reflectance, color coordinates and absorbance curves of treated and untreated samples were then measured, allowing to fully understand the color changes due to the different finish and disperse dye combination
Dendrimer finishing influence on CO/PES blended fabrics color assessment
No full textTextile finishing includes all processes that help to maintain the value or increase the value of the textile material. It encompasses dyeing, printing, and all the finishing treatments to realize durable press, soil release, flame retardant, antistatic, antimicrobial, or water/oil repellency properties. When these properties are realized on dyed textile fabric, one effect could be ascribed to the color change induced by finishing operations. This research focuses on the assessment of color alterations occurring on the dyed cotton/polyester blended fabrics due to the nanoparticle-sized dendrimer (DWR), dendrimer–fluorocarbon (DWOR), and fluorocarbon (FWOR) finishing onto their surfaces. The dependence of color on the surface state of treated textiles is calculated in the context of spectrophotometric measurements. Modification of the surface roughness by reflectance spectrum and the absorbance of finishes in visible range were investigated to determine color changes between the original (control fabric, dyed but not treated) and treated fabrics. As a result of color matching calculated by CIE-Lab values, color change is related to the surface roughness associated with absorbance values of applied finishes. In addition, fabrics mechanical properties were evaluated to estimate if finishing agents application gives rise to other changes, besides color alterations. The fabrics mechanical properties have been found not significantly altered by the aforementioned finishing treatments. These results could be applied for industrial needs (quality control), or in the artistic field of conservation, or restoration (to follow the color of paintings)
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