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Effects of light exposure on textile durability
Abstract
This chapter concerns the field of textiles applications for which resistance to light exposure, especially to sunlight, is most important. The influence of sunlight radiation on the durability of different types of fibres, dyes and other finishing additives is discussed and a mechanism of photochemical destruction proposed. Existing testing methods for the assessment of durability to light exposure of textiles, including evaluation of the changes of physical properties due to light exposure, colour change, and so on are detailed, together with methods of improving durability such as applying different kinds of coatings, chemical finishing and special additives.
... Physical-Chemical Factors as Cause of Textile Deterioration As far as physicalchemical agents are concerned, light, heat, and oxygen are among the main causes of textile alteration (Rubeziene et al. 2012). As regards solar radiation, it comprises visible, infrared (IR), and ultraviolet (UV) components. ...
... Photo-decomposition is accelerated by the presence of heat and moisture. When also oxygen is present, oxidative reactions (such as chain scission and cross-linking) known as photooxidation may occur (Szostak-Kotowa 2004;Rubeziene et al. 2012). The effect of light radiation on colored textiles, such as discoloration, or generation of dark spots is easy to detect, nonetheless light also decreases tensile and tear strength of fabrics (Rubeziene et al. 2012). ...
... When also oxygen is present, oxidative reactions (such as chain scission and cross-linking) known as photooxidation may occur (Szostak-Kotowa 2004;Rubeziene et al. 2012). The effect of light radiation on colored textiles, such as discoloration, or generation of dark spots is easy to detect, nonetheless light also decreases tensile and tear strength of fabrics (Rubeziene et al. 2012). The effect of light can be different depending on the type of textile. ...
Ancient textiles are fragile and several factors can affect their integrity. In the present chapter, the main agents of deterioration of old and new textiles, namely physical-chemical (light, oxygen, heat, and humidity) and biological factors as well as human erroneous interventions will be explored. As far as the biological deterioration is considered, the effects of microbial growth, primary and secondary metabolites (acids, solvents, surfactants, pigments) and enzymes (lipases, proteases, and glycosidases) on textile strength and cleanliness will be described in details. The main fungal and bacterial species involved in the damage (textile discoloration, black and green spots, cuts) will be reported. Adhesive application during restoration procedures is discussed to highlight the risk of glue thickening giving rise to dull precipitates on the fabric. The main strategies for oil-stain and glue removal (both animal glue, such as fish collagen, and vegetal glue, i.e. starch) will be described in the paragraph devoted to biorestoration. Finally, a case study concerning an ancient Coptic tunic housed in the Egyptian Museum of Torino, Italy, and biocleaned by means of gellan-immobilized alpha-amylase from Bacillus sp. will be largely discussed by reporting historical data, adhesive characterization, methods for artificial aging of simulated sample and glue removal from the artwork.
... This includes both natural and artificial light, the latter being less harmful because it is relatively constant in intensity and because it can be controlled and dosed in intensity, type, time and distance. The visible effects of light on coloured textiles are fading of colour or spots, and the less visible effects are decreases in tear and tensile strength of the materials [1]. These effects depend on the raw material from which the textiles are made. ...
... The most resistant are polyester fibres, followed by polyacrylonitrile and polyamide [8]. For these types of fibres, exposure to light causes different degrees of yellowing, a decrease in mechanical strength and a decrease in the degree of polymerization [1]. Temperature is another microclimate factor involved in the deterioration of heritage goods, influencing chemical reactions (oxidation reactions, hydrolysis reactions, etc.) through energy transfer, causing accelerated molecular agitation. ...
Heritage textiles are important evidence of human history. Folk costumes, quilts, tapestries, rugs, hangings, etc. constitute a rich collection of products that are particularly valuable but also extremely fragile. This paper presents the main causes of the deterioration of heritage textiles, followed by a summary of the main bio-treatments that are effective in their case. Essential oils and plant extracts have a strong antibacterial, antifungal and insecticidal effect and are therefore recommended to be used as sustainable alternatives to conventional treatments. At present, bio-treatments used to prevent and reduce the deterioration of heritage textiles are carried out in two ways. One of them targets bioaerosols in museum spaces and the second one targets microbial agents on the surface or in the structure of textiles. The application of bio-treatments on heritage textiles should be done taking into account the specific features given by their fibrous composition, the structure of the materials, their age, the environmental conditions in which they are, etc. At present, these treatments are not yet commonly used for heritage textiles or the spaces in which they are stored or exhibited, even though there are studies that have proven the effectiveness and safety of their use.
... This includes both natural and artificial light, the latter being less harmful because it is relatively constant in intensity and because it can be controlled and dosed in intensity, type, time and distance. The visible effects of light on coloured textiles are fading of colour or spots, and the less visible effects are decreases in tear and tensile strength of the materials [1]. These effects depend on the raw material from which the textiles are made. ...
... The most resistant are polyester fibres, followed by polyacrylonitrile and polyamide [8]. For these types of fibres, exposure to light causes different degrees of yellowing, a decrease in mechanical strength and a decrease in the degree of polymerization [1]. Temperature is another microclimate factor involved in the deterioration of heritage goods, influencing chemical reactions (oxidation reactions, hydrolysis reactions, etc.) through energy transfer, causing accelerated molecular agitation. ...
Heritage textiles are important evidence of human history. Folk costumes, quilts, tapestries, rugs, hangings, etc. constitute a rich collection of products that are particularly valuable but also extremely fragile. This paper presents the main causes of the deterioration of heritage textiles, followed by a summary of the main bio-treatments that are effective in their case. Essential oils and plant extracts have a strong antibacterial, antifungal and insecticidal effect and are therefore recommended to be used as sustainable alternatives to conventional treatments. At present, bio-treatments used to prevent and reduce the deterioration of heritage textiles are carried out in two ways. One of them targets bioaerosols in museum spaces and the second one targets microbial agents on the surface or in the structure of textiles. The application of bio-treatments on heritage textiles should be done taking into account the specific features given by their fibrous composition, the structure of the materials, their age, the environmental conditions in which they are, etc. At present, these treatments are not yet commonly used for heritage textiles or the spaces in which they are stored or exhibited, even though there are studies that have proven the effectiveness and safety of their use.
... As it is known; light, heat, and oxygen have aging effects on textile materials due to their degrading properties. Since UV rays carried by sunlight have a photodegrading effect on textile surfaces, textile products, that are expected to be exposed to sunlight for a long time, must have a high UV resistance [14]. When exposing polymers to UV radiation, an undesirable result may occur. ...
Polyurethane materials can be used industrially in different ways, some of which can be used as textile materials or as auxiliary materials applied to textile materials. Polyurethane stands out as a widely used polymer for coating textile products used in outdoor applications, because of high stability at low temperature, flexibility, no or very little volatile organic component content, high water resistance, pH stability, excellent solvent resistance, weather resistance, and many other chemical and mechanical properties. In the study, cotton, polyester, and viscose fabrics were coated with polyurethane and aged under UV light to investigate the causes and behaviors of the mechanical degradation effects of UV on the coating material and fiber. The results indicate that the PU coating process improves the mechanical properties of textile materials while being exposed to UV rays deteriorates the fabric structure. The deterioration in the structure of raw and coated fabrics with the effect of UV increased the air permeability. According to the results of DSC analysis, the increase in the time of UV exposure did not create significant differences in terms of thermal degradation temperatures in both cotton and viscose fabrics. The glass transition temperatures (Tg) increase with more exposure to UV rays, and the UV exposure time had a negative effect on the melting temperature (Tm) and enthalpy (ΔH) of coated polyester fabrics.
... When cotton is exposed to sunlight, it is subjected to loss of strength gradually. And it is degraded by oxidation when the heat is raised because of absorbing the light intensity [13]. So reflectance property is necessary for cotton fabric [14]. ...
It has, nowadays, become indispensable to get multi-functional properties from a single piece of fabric or garment in the sector of textile and fashion. Cotton fabric is now extremely being utilized in garments all over the world. At the raw stage, cotton fabric has less reflectance, high ignition tendency, moreover the proclivity to be attracted by microorganisms. The strength of the fabric might be deteriorated because of frequent processing. In this study, a single jersey raw (grey) cotton fabric of 150 GSM was processed with a pertinent chemical treatment to convert the reflectance to about 100 % and impart flame resistance property together with the other functional properties. Due to the attainment of high reflectance and flame resistance traits, the heat-absorbing tendency of the fabric became low which improved the comfortability of the fabric. The strength of the processed fabric was increased by 4 %. Crease recovery angle was increased by 57 % in the course way and by 82 % in wales way direction that attributed crease-resistance and more stability to the modified fabric. Moreover, the processed fabric was also able to exhibit antimicrobial properties. Strength improvement, attainment of crease-resistance, and antimicrobial property could enhance the longevity of the fabric. The attainment of multifunctional properties together with the strength improvement simultaneously provided a unique feature to the modified cotton fabric. It was a permanent chemical treatment, and it modified the surface of the fabric, which ultimately enhanced the proclivity of cotton fabric to be more compact or crystalline and more stable. The addition of the new quality of the cotton fabric could endure even after washing. The modified cotton fabric with newly added characteristics could be a good choice to prepare garments with felicitous longevity to protect from heat, fire flame sensitivity. It really could create an opportunity in multi-functional fabric processing as well as modern textiles.
Scientists throughout the world have been exploring the applications of natural textiles in various industrial sectors for their biodegradability, abundance, low density and above all renewability. However, high moisture absorption and subsequent swelling and degradation often limit their application, especially where durability is a key concern. A great attention and efforts have been taken to have proper knowledge in life and durability issues related to the natural textiles. However, the cost and process of natural textiles is higher than that of their synthetic textiles, which also limits their dissemination in different industries. In order to manufacture economical feasibility and durability, natural textiles can be frequently reinforced with different fibres, which increases the life and durability of textiles. Sustainable fashion and durability are growing parts of textile design philosophy. The present chapter discusses the natural fibres and their applications in textiles as well as different factors that affect the durability of natural textiles along with methods for testing and improving textile durability.
The effects of harsh UV radiation (λ = 254 nm) on wool and silk dyed with Hexaplex (Murex) trunculus extract are investigated using HPLC-DAD, colourimetry, SEM and FTIR. Indigotin, 6-bromoindigotin, 6,6′-dibromoindigotin and 6,6′-dibromoindirubin were quantified by an efficient HPLC-DAD method which was validated in terms of linearity, detection and quantification limits, precision and accuracy. Under optimal conditions, the developed analytical scheme offers limits of detection in the range 0.02–0.12 μg mL⁻¹ and satisfactory linearity up to 5.0 μg mL⁻¹. The purple dyes, extracted from the wool and silk fibres, were analysed by the established HPLC method, using the standards addition approach. To evaluate the matrix effect, the matrix-induced signal suppression/enhancement was determined. The accuracy was evaluated by recovery experiments.
The effect of the UV light was initially dramatic, leading to (i) a rapid decrease in the amounts of the four shellfish compounds in the wool/silk fibres and (ii) severe colour changes of the dyed fibres. After extensive (>10 days) exposure in harsh UV light, only slight changes in the dye composition and the colour of the fibres were observed. Overall, larger reductions are reported in the amounts of the dibrominated molecules, whereas indigotin and 6-bromoindigotin appear to be more stable against the UV radiation. However, it is reported that the % relative composition of the shellfish dye is practically unaffected by the degradation process.
Finally, the UV-induced structural and chemical changes of the wool and silk fibres were investigated using SEM and FTIR, respectively.
Algae are being grown for wastewater purification and biofuels production. Their growth on a substrate facilitates these uses by allowing facile separation of algae from the water. Here, we compare different materials to determine which would best serve this purpose. A mixed culture of Anabaena and Chlorella was grown on various synthetic and natural fiber fabric substrates in a trough system with recirculating simulated wastewater. Filter materials studied as substrates for algal growth were muslin, olefin, pellon (acrylic), two types of polyester, and two types of nylon. Biomass accumulation on the various filter substrates was recorded at 7, 14, and 28 days. Filters were weighed before and after the growth periods and changes in dry biomass were recorded. Biomass accumulation was significantly affected by the fabric type. Olefin fostered the greatest increase in biomass while nylon and polyester also supported competitive increases in biomass. Pellon showed the smallest biomass increase and muslin decreased in mass due to material disintegration. Other concerns such as abrasion resistance and UV susceptibility are discussed.
Barrier properties against ultraviolet radiation and the light stability of polypropylene (PP) fibres are very important for light-weight summer fabrics as well as for leisure and sport wear. What is more, the thermal stability of PP composites is required in the spinning process and in the thermal treatment of fibres and fabric. In this paper the effect of selected inorganic nanofillers, such as boehmites (aluminas), organoclays, nano TiO2 and multiwall carbon nanotubes (MWCNT) on the UV barrier properties, photo-oxidation and thermal stability of PP composite fibres was studied. Correlations between the UV barrier properties, light stability and thermal stability of PP composite fibres are also discussed.
The purpose of the research presented was to analyse the influence of the fabric surface cover factor and fabric colour values on the degree of UV ray transmittance and the UV protective factor (UPF). The research was carried out on lightweight coloured fabrics woven in sateen weave with different densities of warp and weft threads and with different colours in the weft. Measurements of the UPF were performed using the "in vitro" method in the range of UVA and UVB ray wavelengths, from 280 to 400 nm. The results of the research confirm the importance of the fabric surface openness for the UV protective factor and expose the influence of the fabric face and reverse sides as well as of colour values L*, C*ab, hab of warp and weft threads on the UPF in sufficiently closed woven constructions. Namely, constructions with less than the 5% surface openness offer excellent protection (UPF above 50), whereas constructions with less than 10% surface openness offer good to very good protection (a UPF above 20). At coverage higher than 95%, the fabrics analysed could be generally divided into three groups with respect to the effectiveness of their UV protection: fabrics of darker colours (black, blue) with extremely high UPF values, fabrics of chromatic lighter colours (yellow, red, green) with UPF values half of those of darker colours in general, and white fabrics (bleached) in which the desired UPF values are not reached regardless of the degree of the cover factor.
An attempt has been undertaken to assess the effect of UV radiation on the structure of polyamide and polypropylene fibres, which are characterised by various macroscopic features, colours and additives. Based on the measurements we performed, we were able to conclude that UV radiation under the exposure conditions used brings about changes in both the fibre structure and mechanical properties. The extent of these changes is clearly dependent on the initial fibre structure, added modifiers and macroscopic features.
UV absorbers and antioxidants topically applied to upholstery fabrics to reduce fading, separately and in conjunction with soil repellent finish formulations containing UV absorbers, were evaluated in this study. Over fifty upholstery fabrics were initially evaluated and fourteen were selected for further study. The fabrics were then topically treated with commercially available soil repellent finishes (a fluorocarbon and a silicone finish) containing UV absorbers or immersion-treated with one of thirteen UV ab sorbers or antioxidants. Following light exposure, color changes were evaluated visually and instrumentally. The results showed that neither the fluorocarbon nor silicone- based soil repellent finishes containing UV absorbers significantly reduced fading in the upholstery fabrics. Furthermore none of the UV absorbers and antioxidants applied to the upholstery fabrics improved lightfastness properties substantially, so they cannot be recommended as additives to soil repellent finish formulations.
Organic and metalorganic dyes have been incorporated into SiO2 coatings using the sol-gel method. It is found that the coatings prepared from sol-gel starting solutions, which were subjected to a ball milling process, have improved light stability. Using optical absorption, atomic force microscopy and microluminescence measurements, it is found that the ball milling process of the starting solutions not only produces better dye dispersion, but there are also some indications that it produces a structure with fewer and smaller pores. These results are in agreement with previous studies, which indicate that the photostability of dyes in metal oxide matrices can be improved when the dye is better dispersed and trapped in more rigid cages. © 2000 American Vacuum Society.
The sun-blocking properties of a textile are enhanced when a dye, pigment, delustrant, or ultraviolet absorber finish is present that absorbs ultraviolet radiation and blocks its transmission through a fabric to the skin. For this reason, dyed fabrics provide better sun protection than bleached fabrics. Since naturally-colored cottons contain pigments that produce shades ranging from light green to tan and brown, it seemed reasonable to postulate that they would provide better sun protection than conventional bleached cotton, and that natural pigments might prove more durable to laundering and light exposure than dyes, but there is no published research on the ultraviolet transmission values for naturally- pigmented cottons. The purpose of this study was to determine the ultraviolet protection (UPF) values of naturally-pigmented cotton in three shades (green, tan, and brown), and the effect of light exposure and laundering on the sun-block- ing properties of naturally-pigmented cotton. Naturally-pigmented cotton specimens were ex- posed to xenon light and accelerated laundering, ultraviolet transmission values measured, and UPF values calculated following light exposure and laundering. The naturally-pigmented cottons exhibited significantly higher UPF values than conventional cotton (bleached or unbleached). Although xenon light exposure and laundering caused some fading, the UPF values of naturally- pigmented cotton continue to be sufficiently high so that all three shades continue to provide good sun protection after the equivalent of 5 home laun- derings and 80 American Association of Textile Chemists and Colorists fading units (AFUs) of xenon light exposure. P
The effect of the benzotriazole type UV-absorbers Tinuvin P and Tinuvin 327 and 2.4-dihydroxy benzophenone in the dyeing of polyester fibres with Viosperse Blue RFS, an azodye of low light fastness at various depths of dyeing and UV-absorber amounts was studied using different application procedures. The dye and UV-absorber uptake and the light and sublimation fastness of the dyed samples were determined and compared to those obtained for the corresponding samples dyed in absence of a UV-absorber. The effectiveness of 2-(2-hydroxy-5-carboxy-phenyl)-2H-benzotriazole in improving the light fastness of polyester fibres dyed with C.I. Disperse Blue 77, Red 86, Yellow 42 and Viosperse Red BS was also studied and compared to that of the above commercial benzotriazole type UV-absorbers. The latter was applied to the fibre in various molar ratios to the dye using two different application procedures: directly in the dyebath and by aftertreatment of the dyed fabrics.
Leaching stability is important when refining paper or textile surfaces with sol-gel silica layers that contain incorporated dyes or other components. First studies show a simultaneous increase in dye and Si concentration in the wash-out solution, indicating that the gradual dissolution of the complete composite layer plays an important role in the leaching process. The leaching stability of silica layers containing incorporated model dyes Aniline Yellow and Acid Orange 10 on different flexible substrates (cellulose paper, polyamide and polyester fabrics) could be improved in a number of different ways: (i) pretreating the substrate with coupling agents such as epoxyalkyl-silanes, (ii) fixing the dye within the silica layer by mixing it with alumina or alkylammonium compounds, and (iii) chemically fixing the dye by bonding it covalently to the silica matrix.
The focus in this report is on the protection of human life from the harmful effects of ultraviolet radiation. Short wavelength ultraviolet radiation is the most harmful and occurs in the spectrum known as UV-C with wavelengths from 280-320nm. The effect of ultraviolet radiation on living organisms and in particular on human skin is discussed in detail. The effects of ultraviolet radiation on a large range of textiles both natural and man-made is the subject of a considerable part of this article. The protection offered by fabrics made from various textiles can be measured by the time difference between skin turning red when exposed to ultraviolet radiation with and without textile protection. An in vitro calculation is also possible and has predictive power. Details of factors governing the quality of protection are discussed and include the use of chemical absorbers (of ultraviolet radiation) as textile coatings.
Ultraviolet absorbers play a vital role in protecting skin from ultraviolet radiation (UVR), including ultraviolet A (UVA), ultraviolet B (UVB), and ultraviolet C (UVC). These UV absorbers are aromatic compounds conjugated with a carbonyl group and have an electron-releasing amine or methoxyl group. Most sunscreens use these UVA for safeguarding skin from the harmful UVR and to avoid medical problems such as skin cancer. Conventional textiles fabrics such as nylon, wool, silk, and polyester also offer protection against UVR, particularly against UVB. Modern textiles incorporates UV absorbers in wet processing enhance the performance of the fabrics and the UVR protective clothing. Companies such as Ciba Specialty Chemicals and Clariant have developed several UV absorbers to be used with various types of fibers and fabrics. The increasing awareness of personal protection and the performance of textiles is resulting into the versatile use and demand for these products.
The effectiveness of selected antioxidants and ultraviolet absorbers in reducing colour change and fibre degradation in treated fabrics was studied to establish whether beneficial synergistic interactions exist between antioxidants and ultraviolet absorbers. The usefulness of the products as additives to drycleaning solutions for museum textiles and as additives to soil-repellent finishes was also considered. There are 29 references.
We present the results of an investigation which shows that the yellowing of wool fibre which occurs during light exposure and treatment with boiling water is reduced by pre-treatment of loom state wool fabric with perchloroethylene. The changes in light reflectance and the yellowing index of the treated wool fabric were found to correlate with the data of wool fibre strength, permanent set degree, solubility in urea-bisulphite solution, fluorescence emission and thermogravimetric analysis.
Textiles provide protection from ultraviolet rays depending on the type/construction of the fabric and can be damaged by light exposure. The biological effect of UV radiation on the skin and the complicated mechanisms in humans leading to skin cancer are examined. UV radiation and reaction of impingement on textiles, UV-permeability of textiles, measuring methods, UV Standard 801 and ultraviolet and sun protection factor are described. Yarns, Textile fabric and Finishing are major sections, subdivided. Yarns cover fibre properties, man-made fibres with UV protection and UV protection in the fibrous substance. Textile fabric deals with fabric construction, the protective effect of textiles and UV protection with nonwovens. Finishing explores chemicals for UV protection, colour and depth of colour, moisture impairment of protective action, the effect of UV radiation on textiles and sun protection from the washing machine. Climatic changes leading to increased skin cancer are summarised. (8 fig 1 tab).
Cotton fabric (100% cotton) and synthetic fabric (65% polyester and 35% cotton) were exposed at five selected sites in urban and industrial districts in Cairo city for a period of 15 months. The changes in the physical properties of the exposed textiles were investigated. The results indicated that the tensile strength of all the exposed samples was decreased, for warp and weft directions by different ratios, at all sites as a function of time of exposure. The highest deterioration in tensile strength was 86.2%, detected for cotton samples exposed in the industrial area. The lowest percentage loss of tensile strength was 58%, detected in the purely residential area of low population density. The loss in tensile strength of synthetic textile samples ranged from 54 to 73%. The difference between the tensile strength for sheltered and unsheltered textile samples increased with increasing time of exposure, especially with increasing solar radiation intensity in the summer. The cotton fabric lost about 25% of its tensile strength, and the synthetic fabric lost about 19.5% of its tensile strength after 15 months exposure to direct solar radiation. The percentage loss of elongation (elasticity) for cotton and synthetic fabric ranged from 72% to 89% and from 67.2% to 88.2%, respectively. Several conclusions and recommendations are also given.
In situ, quantitative infrared spectrometry has been used to measure the evolution of carbon dioxide during the photo-degradation of pigmented and unpigmented acrylic-emulsion paint films. It is demonstrated that the method permits a fast and convenient way of assessing the resistance of such paints to UV degradation. However, it is also shown that valid comparisons of paints prepared with different grades of titanium dioxide, but with the same acrylic emulsion, require careful selection and control of the experimental conditions. Thus, the relative importance of (a) direct photochemical oxidation of the binder and (b) indirect photo-catalysed oxidation (mediated by titanium dioxide) depend not only on the spectral distribution of the radiation source, particularly the output between 300 and 400 nm, but also on the humidity of the ambient atmosphere. The increased rate of oxidation with increased humidity is not unexpected, but the size of the effect is unexpectedly high. In addition, there is some carbon dioxide formation during irradiation of the paint film in nitrogen and further investigation of this phenomenon is in hand. For both pigmented and unpigmented films, the rate of carbon dioxide evolution is sensitive to the film thickness. The dependence of the oxidation rate on the thickness of clear, unpigmented films is consistent with the measured UV absorption. However, for pigmented films, this dependence extends over greater film thicknesses than predicted by a simple model based on paint film optics.
The 172 nm ultraviolet (UV) excimer light was exposed to textile fabrics of acetate, nylon 6, poly (ethylene terephthalate), acrylic and polypropylene. No significant changes in the tensile extension parameters and the surface reflectance of the fabrics due to the UV exposure were observed. The water contact angle was measured by the Wilhelmy technique using a single fiber that was taken from the fabric. Remarkable increase in wettability was accomplished by the UV irradiation of 1 minute. The capillary wetting and the moisture absorption of the fabrics, which were determined electrically, were found to increase by the UV exposure. The effect of the UV exposure on detergency was examined using a poly (ethylene terephthalate) plate on which model particulate soil was deposited. The removal was found to increase after the UV treatment. It was concluded that the exposure of UV excimer light to synthetic textile fabrics made it possible to improve their serviceability properties.
After determining the wet bundle strength of sunlight irradiated wool, the broken fiber ends are evaluated optically by electron microscope. Three different modes of fiber fracture are identified. Due to the breakage morphology, we assume that the histological wool components are damaged to a different extent as a function of ir radiation time. Thus, the frequency of the breakage modes may serve to indicate the stage of fiber damage. We suppose that the initial step of photodamage is the pho tooxidation of the internal lipids, because they are obviously modified after a very short time of irradiation, while the keratin components are visibly intact. After long irradiation periods, the fibrous structure of the keratin fibrils is no longer recognizable.
In recent years conservators have begun to recognise that preventive conservation is as important as active conservation. Conservation treatments may play a role in accelerating the deterioration of museum artefacts in the long term. Accelerated tests were designed to find conservation materials, which would be safe for long-term use and would not cause degradation of museum artefacts. This study concerns the long-term effect of different conservation materials on the properties of linen textiles. Linen textile samples were treated with 5 different types of polymers, 4 different types of fungicides and 4 different types of deacidifying agents to evaluate the long-term effect of these materials on the physical and chemical properties of linen textiles. Three different types of accelerated ageing methods, heat, light and soil were used in this evaluation. The change of the physical and chemical properties of the untreated and treated linen textiles after ageing was assessed by different methods. The results showed that both treated and untreated linen textiles became progressively darker and showed progressive losses in tensile strength after ageing by different methods. X-ray results show that the ageing of the linen samples slightly decreased crystallite size in the longitudinal dimensions, also decreasing the total crystallinity compared to unaged samples. Results obtained by IR show changes in chemical properties of treated and untreated linen textiles after ageing by different methods. The results of this study will assist a conservator who seeks information about changes in the properties of linen textiles which may occur in the long term when they are treated with common conservation treatments.
It has been found that many substituted benzophenones are very effective as ab sorbing agents for ultraviolet light. Unlike most organic compounds which have been used for this purpose, this new class of absorbers is quite resistant to degradation. The physical properties and uses of these ultraviolet absorbers are discussed in detail.
The ultraviolet component of solar radiation extends from 400 down to about 290 mμ. A major objective in the development of stable organic absorbers has been to achieve a maximum of ultraviolet absorbing power with a minimum of visible color.
A variety of interesting applications have been found for these absorbers. They may be used in protective coatings or filters to protect substrates from ultraviolet light. They are usually quite effective as stabilizers when incorporated in ultraviolet sensitive materials. There are many potential applications of ultraviolet absorbers in the textile industry. They could be incorporated in fabric coatings or in finishes applied to yarns or fabrics that are known to degrade in outdoor exposure because of ultraviolet light. They can improve markedly the light fastness of those dyes which are faded by ultra violet light. Some of the problems involved in these applications are discussed.
Dye molecules are incorporated into silica matrices for textile dyeing. One aim is to develop a method to use inexpensive dyes with simple molecular structures for dyeing completely different kinds of textile materials. Altogether, three different classes of dyes are incorporated—positively charged Astrazone Blue, negatively charged Alizarin S Red, and uncharged Sudan II Blue—using an acidic sol-gel process starting with a solution of tetraethoxysilane and crosslinking agents and the dye in ethanol. By means of dip-coating and padding, these solutions are deposited on three different textiles, polyester, poly amide, and cotton. The incorporation properties were mainly influenced by the properties of the dyes, but improved wash fastness can be achieved by modifying the matrix composition.
Quartz, Kevlar, carbon, and glass filaments were irradiated by ultraviolet ray with various periods. Tensile strength of the treated fibres was tested and analyzed, and the outward appearance of the treated filaments was shown.
A methodology, which combines experimental evidence and theoretical calculations, able to give a molecular interpretation and a quantification of the photooxidation of polyolefins is here derived. The methodology involves the analysis of experimentally recorded infrared spectra in combination with density functional theory calculations. Environmental effects are taken into account by exploiting the polarizable continuum model. A test against polyethylene and polypropylene samples UV-irradiated under the conditions used for the photocoating is reported. The results obtained with the combined theoretical/experimental methodology are in good agreement with previous findings obtained by exploiting more complex purely experimental approaches.
The photofading behaviour of carthamin in cellulose acetate film was investigated. A contribution from singlet oxygen to that fading was suggested. Phenyl esters containing nickel sulphonate quenching groups were prepared and the protecting effect of these compounds towards the photofading of carthamin was examined in cellulose acetate film. It is proposed that nickel sulphonate derivatives of phenyl esters can be applied as effective stabilisers against the fading of natural dyes.
The effect of a UV absorber on the lightfastness of natural dyes has been investigated. Wool and silk fabrics, dyed with natural dyes with or without mordants, were aftertreated with two UV absorbers. This treatment improved the lightfastness of the mordant-dyed fabric without affecting its colour or shade. The extent of photofading was evaluated by measuring the colour difference, ΔE, of the dyed sample before and after a 20 h period of irradiation under a xenon arc lamp. The uptake of the UV absorber on wool was much higher than that on silk.
The effect of sunlight and drying methods on the strength of Real Wax printed cotton fabrics produced in Ghana was determined. Warp and weft specimens were washed using the Standard Launder-Ometer (Gyrowash 315). Each laundered or unlaundered specimen was aired or dried on a flat surface or on clothesline in the sun or shade for 42 h. The breaking strengths of controlled and treated specimens were determined using the tensile testing machine (Hounsfield H5K-S) and the average percentage loss in strength calculated. The analysis of variance and least significant difference for the separation of means were used to test significant differences between the treatments. Whether dried or aired, sunlight caused more loss in strength than shade. Laundered specimens lost more strength in the sun or shade than those unlaundered. Specimens dried or aired on a flat surface in the sun or shade lost more strength than those on clothesline. There were significant differences (P ≤ 0.05) as a result of the different treatments in the warp direction. For the weft specimens, there was a significant difference between only the aired and washed specimens. Conclusions and future research directions are discussed.
An attempt was made to deposit a nanocoating onto a cotton textile substrate using a layer-by-layer self-assembly approach. Chitosan, a natural biopolymer with polycationic characteristic, was used as a polyelectrolyte along with poly(sodium-4-styrene sulfonate) as an anionic polyelectrolyte for the first time on a textile substrate using this technique. The nanocoated surface was evaluated for surface characteristics such as the contact angle and scanning electron microscopy. The effect of ultrasonication during the intermediate washing steps was explored. Ultrasonication during the washing steps clearly helped in depositing more uniform bilayers onto individual fiber surfaces; this contrasted with the deposition of a continuous coating layer, which was nonuniform and had a lot of surface cracks. The use of this novel method for depositing chitosan onto cotton imparted antimicrobial properties to the fabric without adversely affecting its flexibility, feel, or breathability. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Textiles, with appropriate light absorbers and suitable finishing methods, can be used as ultraviolet (UV) protection materials. In this study, we investigated the effects of nano-TiO2 particles on the UV-protective and structural properties of polypropylene (PP) textile filaments. Master batches of PP/TiO2 nanoparticles were prepared by melt compounding before spinning, and filaments incorporating 0.3, 1, and 3% TiO2 nanoparticles were spun in a pilot melt-spinning machine. The structural properties of the nanocomposite fibers were analyzed with scanning electron microscopy, X-ray diffractometry, differential scanning calorimetry, and tensile tests. The UV-protection factor was determined to evaluate the UV-protective properties of the filaments. In conclusion, although the structure and mechanical properties of the nanocomposite filaments were slightly affected by the addition of nano-TiO2, the UV-protective properties of the PP filaments improved after treatment with nano-TiO2, and the nanocomposite filaments exhibited excellent UV protection. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Various nickel arylsulphonates were synthesised and their protecting effects on the photofading of CI Basic Violet 3, CI Acid Red 94, CI Acid Red 87 and CI Acid Blue 74 examined on nylon fabric. The rates of photofading of the dyes were remarkably suppressed in the presence of nickel salts, while the addition of ultraviolet absorbers and conventional stabilisers afforded little retardation of the rate of fading. The antimicrobial activity against two species bacteria of nickel salts was also examined. This aftertreatment technique was shown to be safe for the environment and human health.
Silk reinforced gelatin based composites were prepared by compression molding. The fiber content in the composite was 20 wt.%. Tensile strength (TS), tensile modulus (TM), bending strength (BS), bending modulus (BM), impact strength (IS) and hardness of the composites were found 44.5 MPa, 0.65 GPa, 63 MPa, 3.7 GPa, 5.1 kJ/m2 and 96 shore A respectively. The environmental effect on composite was observed by simulating weathering test and the composite lost 15.2% TS at the end of 30 h of the weathering testing period. The biodegradation test shows that the composite degrades very quickly and losses 52.1% weight at the end of 24 h. Morphological analysis was carried out to observe fracture behaviour and fiber pullout of the samples.
The color fastness to washing of silk fibers dyed with scarlet dye was improved by the deposition of a thin polymer film which prevented desorption of the dye in standard soap solution. Dyed silk fibers were coated with polyelectrolytes multilayers (PEM) by following the so-called layer-by-layer deposition method in which up to 30 layers of cationic poly(diallyldimethylammonium chloride) and anionic poly(sodium 4-styrene sulfonate) were deposited. The growth of the film was con firmed using attenuated total reflectance Fourier transform infrared spectrophotometry and the dye exhaustion from the silk fiber was monitoied using UV-Vis spectroscopy. The ability of the PEM to act as an electrostatic barrier against the release of the negatively charged dye was investigated as a function of the terminating top layer. The results showed that the negative layer-terminated PEM is more efficient at preventing the release of the dye than the positively terminated PEM.
The degree of plasma‐induced hydrophilization and the stability of the treatment are closely linked to the textile structure and the weave construction. This study investigates the plasma activation of polyester (PES) fabric structures to improve their wettability, as well as the aging effects. The hydrophilic modification is carried out by low pressure plasma treatments using oxygen containing gaseous mixtures (Ar/O 2 and He/O 2 ), and it is characterized by calculating contact angles (static and advancing) from capillary rise tests with water. In all cases, the wettability of plasma‐treated PES fabrics is improved significantly due to the formation of polar groups on the surface. In particular, the hydrophilicity of looser structured fabrics is improved remarkably as compared to tightly woven fabrics. Furthermore, the capillary phenomenon in fibrous assemblies is also described in this study.
SEM image of a tightly woven fabric and the schematic representation of the liquid flow within a plasma‐hydrophilized fabric by capillary forces.
magnified image SEM image of a tightly woven fabric and the schematic representation of the liquid flow within a plasma‐hydrophilized fabric by capillary forces.
Polyamides were considered to be among the new and exciting industrial materials of the late 1930s and their use has since undergone steady, substantial growth worldwide. Nylon fibres possess excellent tensile strength, elasticity and resilience and are used in the production of clothing, nonwovens, carpets, hosiery, rope and tyre cord [1]. In the plastic form, nylons are used in the manufacture of brush bristles, industrial conveyor belts, hot air balloons, airbags for cars, zips, gears, wire insulation and piping. However, polyamide fibres, especially the aliphatic type, display some deficiencies. Experience has shown that for many applications, the environmental stability of aliphatic polyamides needs improvement against thermal and ultraviolet (UV) degradation. Under photolytic and/or thermal ageing conditions, nylon undergoes undesirable changes in mechanical properties, becomes brittle and becomes yellow in colour. The behaviour of aliphatic polyamides on exposure to heat and irradiation has therefore attracted a significant amount of attention. In recent years there has been an increasing emphasis on preventing the loss of fabric strength in polyamides caused by exposure to various environmental conditions. This review addresses the issues regarding the degradation of nylon 6.6, which is the most widely used variety of nylon worldwide.
The embedding in sol-gel coatings can improve the fastness properties of dyes on textiles. The aim of this study is to investigate,
whether it is necessary to apply dye and sol together in one step or the application of dye and sol can be performed in separate
steps. For practical applications, it can be of high interest to apply sol and dye separately, because by this the fastness
properties of once coloured textiles can be improved by sol-gel coatings or an uncolored sol-gel treated fabric can be dyed
afterwards with higher fastness properties.
For this, modified silica sols and dye molecules were applied in combination on textiles.
The investigations were performed with the two triphenylmethane dyes Malachite Green and Guinea Green. These dyes were applied
using four different methods – without sol, applied before or after sol treatment and together with the sol. The silica sols
were applied in different concentration. It was demonstrated that the application together with the silica sol or the aftertreatment
of dyed textile with silica sol lead to significant improvement of leaching fastness. Also the low bleaching fastness of the
triphenylmethane dyes can be enhanced significantly.
Since the discovery of hindered amines as effective stabilizers against the photodegradation of polymers, the stabilization mechanism of Hindered Amine Light Stabilizers (HALS) has been a subject of discussion. Nevertheless, a complete mechanism has not yet been formulated.In this paper, the degradation of an unstabilized and two HALS-stabilized polyethylene (PE) films is described. The degradations are characterized by measuring: the oxygen uptake, the formation of CO and CO2, the FT-IR spectra, the stabilizer concentration and the oxygen content.The oxygen uptake of the unstabilized PE film led to the expected changes in the IR spectra and to the embrittlement of the film. The oxygen uptake by the HALS-stabilized films caused only minor changes.At an oxygen uptake of 900 mmol per kg of polymer, the HALS-stabilized PE films showed only minor differences in their IR spectra and in their mechanical properties, while the unstabilized material showed an enormous change in its IR spectrum and became totally brittle.Thus, for the HALS-stabilized materials and for the unstabilized materials, the mechanism of oxygen uptake must be different. The difference between the results for the unstabilized and the HALS-stabilized polymers are explained assuming that the initiation of the photodegradation of PE is due to charge transfer complexes.
Exposure to simulated ultraviolet sunlight at 50 °C and 50% relative humidity caused a significant deterioration in the mechanical performance of polyaramid and polyaramid/polybenzimidazole based outer shell fabrics used in firefighter jacket and pants. After 13 days of exposure to these conditions the tear resistance and tensile strength of both fabrics decreased by more than 40%. The polybenzimidazole containing fabric was less impacted by these conditions as it maintained approximately 20% more of its mechanical properties. These conditions also significantly degraded a water repellant coating on the fabric, which is critical to the water absorption performance of the outer shell fabrics. However, these conditions had little impact on the ultraviolet light protection of the outer shell as both fabrics still blocked 94% of ultraviolet light after 13 days of exposure. Confocal microscopy showed these conditions caused significant surface decomposition of and the switch from ductile to brittle failure of the polyaramid fibers. Cleavage of the amide linkages and the formation of oxidation species (as observed by Infrared spectroscopy) suggested these conditions caused photo-oxidation of the polyaramid fibers. There was little evidence of polybenzimidazole fiber degradation.
Ultra long duration balloons (ULDB), currently under development by the National Aeronautics and Space Administration (NASA), requires the use of high strength fibers in the selected super-pressure pumpkin design. The pumpkin shape balloon concept allows clear separation of the load transferring functions of the major structural elements of the pneumatic envelope, the tendons and the film. Essentially, the film provides the gas barrier and transfers only local pressure load to the tendons. The tendons, in the mean time, provide the global pressure containing strength. In that manner, the strength requirement for the film only depends on local parameters. The tendon is made of p-phenylene-2,6-benzobisoxazole (PBO) fibers, which is selected due to its high strength to weight ratio when compared to other high performance, commercially available, fibers. High strength fibers, however, are known to degrade upon exposure to light, particularly at short wavelengths. This paper reports the results of an investigation of the resistance of four commercial high strength fibers to ultra violet (UV) exposure. The results indicate that exposing high strength fibers in continuous yarn form to UV led to serious loss in strength of the fibers except for Spectra® fibers. The adverse changes in mechanical behavior occurred over short duration of exposure compared to the 100 day duration targeted for these missions. UV blocking finishes to improve the UV resistance of these fibers are being investigated. The application of these specially formulated coatings is expected to lead to significant improvement of the UV resistance of these high performance fibers. In this publication, we report on the mechanical behavior of the fibers pre- and post-exposure to UV, but without application of the blocking finishes.
Samples of thermal bonded polypropylene non-woven fabrics were exposed to light from two TUV 30W G30T8 Philips lamps (λ = 253.7 nm) in a covered open-air chamber at room temperature (25 °C and 55% relative humidity) for different periods of time. In order to determine the state of degradation, the samples were examined by optical microscopy, scanning electron microscopy, staining with an isopropanol solution of methylene blue and Sudan III, colourimetry, Fourier transform infrared (FTIR) spectroscopy and density measurements. Although the bonded areas formed under complex thermal and mechanical deformations during the fabric production, no localized staining was observed. The colour of the irradiated and stained fabrics changed uniformly due to the even production of polar groups in the process of irradiation. It was found that the change of redness and blueness of degraded and stained samples can be correlated linearly with the evolution of POOH groups as determined by FTIR spectroscopy. Products containing carbonyl (CO), hydroxyl and/or hydroperoxide (POOH) groups increase with time of degradation with a non-linear relation. It was also observed that the density and 997 cm−1/972 cm−1 FTIR absorbance ratio increases with degradation time. Density fluctuation and the build up of degradation products caused fibre cracks and embrittlement.
This article reviews the current state of the art of weathering test design. It describes the primary environmental and procedural variables involved in the design of a weathering test. The relationship between the environmental variables and the current techniques available to accelerate the degradation process either outdoors or in the laboratory is discussed. Primary environmental variables include light, heat and moisture; procedural variables include exposure cycle, exposure time and test initiation. Both laboratory accelerated and outdoor weathering procedures are addressed in the paper. Each of the variables is briefly examined and examples of practical solutions given. The most commonly used exposure racks, boxes and cabinets as well as laboratory accelerated testing devices and instrumentation for monitoring and reporting climatological data are described.
This paper describes the effects of applying coatings of an acrylic polymer containing nanoparticles of zinc oxide (ZnO) on the fading rate in artificial sunlight of polyester fabrics dyed with disperse dyes containing anthraquinone and benzopyran chromophores. Factors affecting the transparency and UV absorbance of the coatings are discussed. Removing the UV component of sunlight with ZnO nanoparticles markedly decreased the fading rate of the dyes, provided the polymer/ZnO film was not in direct contact with the fabric. When the treatment was applied directly to the fabrics, however, the protection against colour fading was different for the two dyes studied. Whereas the rate of colour fading of a benzopyran dye, of relatively low lightfastness, was decreased by the polymer-ZnO film, the treatment increased the fading rate of the dye of higher lightfastness, based on anthraquinone. This effect has been attributed to the generation of reactive oxygen species (ROS) when ZnO is exposed to UV. The effect of decreasing the photoactivity of ZnO by doping with manganese has been examined. For the benzopyran dye, the UV protection was greatly increased, whereas a much smaller improvement was found for the anthraquinone-based dye.
The effect of natural sunlight on four polyamide monofilament yarns and four polyamide multifilament twines was studied. The samples, each of different RTex were exposed to 180 days solar radiation and sub-samples were drawn at intervals to study the effect on breaking strength and elongation at break. Significant reduction in both breaking strength (P < 0.01) and elongation at break (P < 0.01) have been recorded in the test samples due to weathering. Breaking strength reduced linearly with the period of exposure, while no such linear relationship was found in the case of elongation at break.
Nanoparticle-embedded acrylic coatings that can absorb copious amounts of UV radiation yet scatter little were developed to protect base fabrics from sun-induced degradation. Zinc oxide and titanium dioxide nanoparticles with diameters ranging from 15 to 70 nm were used. Nanoparticles (5 wt%) were dispersed in acrylic emulsions. Nanoparticle-embedded acrylic films of 10 μm and 20 μm thick were prepared and bonded to Kevlar fabric. Mechanical tests as well as infrared, visible and UV spectroscopy were used to characterize nanoparticle-embedded acrylic emulsions and coated Kevlar fabric.The changes in mechanical and chemical properties of Kevlar fabric after a day and week of intense UV exposure were assessed using tear and strip tensile testing, UV, visible and infrared spectroscopy, and wide and small angle X-ray analysis. Tear and tensile data, with support from UV results, showed that 20 μm nanoparticle-embedded coatings largely prevented degradation of Kevlar fabric, allowing only 5% of the degradation that occurred in the unprotected fabric after a week of UV exposure.
The layer-by-layer (LbL) deposition of poly(sodium 4-styrene sulfonate) (PSS) and poly(allylamine hydrochloride) (PAH) over cotton fibres is reported. Cotton fibres offer unique challenges to the deposition of nanolayers because of their unique cross section as well as the chemical heterogeneity of their surface. Cationic cotton substrates were produced by using 2,3-epoxypropyltrimethylammonium chloride. Attenuated total reflectance FTIR, x-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM) were used to validate the presence of the nanolayers as well as to corroborate their self-organized structure. TEM images indicated conformal and uniform coating of the cotton fibres. XPS spectral data were found to be in quantitative agreement with previous published work that studied the LbL deposition of PSS and PAH over synthetic substrates.
This research paper presented a novel approach of developing excellent protection from ultraviolet (UV) radiation of cotton fabrics by means of water vapor permeable (WVP) coatings containing multiwall carbon nanotube (MWNT), a stable and strongly UV absorbing species. The WVP of MWNT containing UV protective coatings of the present development are formed from solution polymer of hydrophilic polyurethane (HPU). MWNTs were dispersed in HPU solution by functionalization of MWNT. The nanotube containing HPU coating shows excellent protection against UV radiation, with only 1 wt % of MWNT (calculated based on solid content of the polymer), a UV Protection Factor (UPF) of 174 and with 2.5 wt % of MWNT a UPF of 421 was obtained, which stated excellent protection (UPF 50) according to the Australian/New Zealand standards. Scanning electron micrographs of coated fabrics surface showed a film like polymer coating, confirming the fabric surface was successfully coated by polyurethane. The coated fabrics would maintain very good water vapor permeability, hence confirmed the wearing comfort. Room temperature (20-23°C) range soft segment crystal melting of HPU enhances the permeability of coated fabrics
The wool fibre has a complex morphology, consisting of an outer layer of cuticle scales surrounding an inner cortex. These two components are hard to separate effectively except by using harsh chemical treatments, making it difficult to determine the susceptibility of the different components of the fibre to photoyellowing. An approach to this problem based on mechanical fibre modification is described. To expose the inner cortex of wool to different degrees, clean wool fibres were converted into ‘powders’ of various fineness via mechanical chopping, air-jet milling, ball milling or their combination. Four types of powdered wool (samples A, B, C and D) were produced with reducing particle size distributions and an increasing level of surface damage as observed using SEM. Sample A contained essentially intact short fibre snippets and sample D contained a large amount of exposed cortical materials. Samples B and C contained a mixture of short fibre snippets and cortical materials. Solid wool discs were then compressed from the corresponding powder samples in a polished stainless steel die to enable colour measurement and UV irradiation studies. ATR-FTIR studies on powder discs demonstrated a small shift in the amide I band from 1644 cm−1 for disc A to 1654 cm−1 for disc D due to the different structures of the wool cuticle and cortex, in agreement with previous studies. Similarly an increase in the intensity ratio of the amide I to amide II band (1540 cm−1) was observed for disc D, which contains a higher fraction of cortical material at the surface of the disc.