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Mechanical Properties and Stability to Light Exposure for Dyed Egyptian Cotton Fabrics with Natural and Synthetic Dyes
Abstract
Synthetic dyes are more available than natural dyes were in the past, because of lower prices and wider ranges of bright shades with considerably improved color fastness properties. In current years, concern for the environment has created an increasing demand for natural dyes, which are friendlier to the environment than are synthetic dyes. The aim of this work is to study the effect of dyeing cotton fabrics with both a natural dye (henna) and a synthetic dye (Remazol blue) on some mechanical properties and those of stability to light exposure. The undyed and dyed cotton fabrics were tested for their mechanical behaviors expressed as tenacity (N), elongation %, and work-breaking (N · m). They were also tested for shrinkage and crease recovery angle. The stability to light before and after 100 h exposure was examined by investigating the microstructure [using x-ray diffraction (XRD)] and macrostructure [using a scanning electron microscope (SEM)] and the reflection spectra. The results proved that the cotton samples dyed with Henna dye have higher mechanical properties than those dyed with “Remazol” reactive dye. Moreover, the light fading behaviors of both synthetic and natural dyes were studied in terms of the reflection spectra (400-800 nm), microstructure, and macrostructure of the sample's fibers.
... Alum, chromium, stannous chloride, copper sulfate, ferrous sulfate, and other substances are common mordants (Singh and Bharati, 2014) [29] . Because synthetic dyes are more affordable, offer a greater variety of vibrant shades, and have significantly better fastness properties than natural dyes, the textile dyeing industry currently uses an excessive amount of synthetic dyes to meet the required coloration of textiles for global consumption (El- Nagar et al., 2005;Iqbal et al., 2008) [11,17] . Such dyes have detrimental effects on the eco-balance of the environment and pose major health risks when applied (Bruna and Maria 2013; Goodarzian and Ekrami 2010;Jothi 2008) [8,13,18] . ...
... Alum, chromium, stannous chloride, copper sulfate, ferrous sulfate, and other substances are common mordants (Singh and Bharati, 2014) [29] . Because synthetic dyes are more affordable, offer a greater variety of vibrant shades, and have significantly better fastness properties than natural dyes, the textile dyeing industry currently uses an excessive amount of synthetic dyes to meet the required coloration of textiles for global consumption (El- Nagar et al., 2005;Iqbal et al., 2008) [11,17] . Such dyes have detrimental effects on the eco-balance of the environment and pose major health risks when applied (Bruna and Maria 2013; Goodarzian and Ekrami 2010;Jothi 2008) [8,13,18] . ...
The indigenous tribes of NorthEastern India have long engaged in the practice of rearing Eri silkworms and making Eri silk fabric. The state of Assam, in particular, is widely recognized for its significant contribution to the nation's production of raw silk. The state's marginal farmers encounter several obstacles throughout the fabric-making process and may not receive the results they were hoping for. Since Assam is one of the most biologically diverse states in the country, the current shift in the fashion and textile industries toward sustainability and eco-friendliness can have a significant impact on the creation of natural dye from a variety of natural resources. In order to determine the color implications for Eri silk yarn, the current study focuses on extracting natural dye from available floral samples from the Nagaon district.
... Textile dyeing industry at present uses excessive amount of synthetic dyes to meet the required coloration of global consumption of textiles due to cheaper prices, wider ranges of bright shades, and considerably improved fastness properties in comparison to natural dyes ( El-Nagar et al. 2005;Iqbal et al. 2008. The application of such dyes causes serious health hazards and influences negatively the eco-balance of nature ( Bruna and Maria 2013;Goodarzian and Ekrami 2010;Jothi 2008). ...
... Textile dyeing industry at present uses excessive amount of synthetic dyes to meet the required coloration of global consumption of textiles due to cheaper prices, wider ranges of bright shades, and considerably improved fastness properties in comparison to natural dyes ( El-Nagar et al. 2005;Iqbal et al. 2008. The application of such dyes causes serious health hazards and influences negatively the eco-balance of nature ( Bruna and Maria 2013;Goodarzian and Ekrami 2010;Jothi 2008). As a result, natural dyes are among the promising options for developing a greener textile as well as for construction of medicinal clothings. ...
Dyeing is the art of imparting hues and tints to yarns, fabric and other materials by employing colouring matter. Colouring matter can be obtained from both natural and synthetic sources. Synthethic dyes impart vibrant colour and are widely used but it causes carcinogenicity and inhibition of benthic photosynthetic. Recent reviewed of interest in the use of natural dye in textile colouring is due to the stringent environmental standard imposed by many European countries in response to the toxic and allergic reaction associated with synthethic dyes. Germany was the first to take initiative to put ban on numerous specific azo-dyes for their manufacturing and applications. Netherlands, India and some other countries also followed the ban (Patel, 2011) .A varieties of Colour, shades from vibrant jewel tones to dusky heathers and pastels can be obtain from different sources. Various methods are used for colour extraction as well as different extraction procedure depending upon the type of yarns or fabric differes. They are considered as eco-friendly, nontoxic, medicinal properties fitting into similar trends of repurposing, up cycling which is very important for maintaining environmental balance.
... Datisca contains a group of distinguished flavonoids mainly datiscetin, rutinoside, kaempferol, quercetin and galangin, which make it easy to identify the plant. Henna is a brilliant dye that is made from the leaves of Egyptian privet (Lawsonia inermis L.), which contains lawsone (also known as hennotannic acid), and has been used for centuries, since its ease of applying on textiles, especially on cotton by all known methods (El-Nagar et al., 2005), and it gives red-brown hues. These plant sources were also used by the Turkish dyers (McNab et al., 2009), however the dyer's chamomile (Anthemis tinctoria L.), a herbaceous plant with yellow flowers that are native almost worldwide with luteolin, apigenin, quercetin, and chlorogenic acid as major components, and quercetagetin and patuletin as minor components (McNab et al., 2009;Eser et al., 2017), was detected only in a few Ottoman textiles (Karapanagiotis and Karadag, 2015). ...
... Textile dyeing industry at present uses excessive amount of synthetic dyes to meet the required colouration of global consumption of textiles due to cheaper prices, wider range of bright shades, and considerably improved fastness properties in comparison to natural dyes (El-Nagar et al., 2005;Iqbal et al., 2008). However, the production of these synthetic dyes is dependent on petrochemical source, and some of these dyes contain carcinogenic amines (Hunger, 2003). ...
... Doğal boyamacılık ve doğal boyarmaddeler tekstil tarihi kadar eski olup Pawlak et al. (2006), özellikle Mezopotamya ve çevresinde kullanıldığı bilinmektedir (Anonim 2007, Duff et al. 1977. On dokuzuncu yüzyılda kimyasal boyarmaddelerin üretimi ile birlikte hayvansal ve bitkisel kökenli boyarmaddelere) olan ilgi azalarak günümüze kadar devam etmiştir (El-Nagar et al. 2005). Sağlığa zararlı sentetik boyarmaddeler halen kullanılmaya devam etmektedirler. ...
Dünya çapına yayılan pandemiden dolayı virüsten korunmak için maske kullanımı hayatımızın bir parçası haline gelmiştir. Boyalı maskelerin cilde teması ve solunum yolu ile akciğerlere verdiği zararlardan dolayı bitkisel kökenli boyarmaddeler rağbet görmektedir. Bu çalışmada sarı renk pigmenti içeren safran ve kahverengi renk pigmenti içeren tarçın bitkisi kullanılarak boyama işlemi gerçekleştirilmiştir. Boyama için kullanılan cerrahi maskeler üç katlı olup Polipropilen (PP) dokusuz yüzey filament serme ve ısıl bağlama (spunbond) yöntemi ile üretilmişti. Renk kuvvetini ve haslık değerlerini arttırmak için tuz (NaCl) ve maden suyu (Na-HCO3) kullanılarak son mordanlama ile boyama işlemi gerçekleştirilmiştir. Boyalı cerrahi maskelere, ter ve tükürük renk haslık değerleri olan L*, a*,b*, K/S, ∆E verileri ölçülmüştür. Sonuç olarak, mordanlama renk değerlerinde pozitif etki yaratmıştır. Ter ve tükürük haslık değerleri ise yüksek bulunmuştur. Bitkisel içerikli doğal boyama maskelerin boyanmasında bu konuda çalışma yapan tüm akademisyen ve sektör için başarılı bir şekilde uygulanabilen alternatif bir yöntem olarak kullanılabilir.
... Afterward, MB was replaced by chloroquine and other synthetic drugs from its derivatives without staining properties. In textile industries, MB is widely used as coloring agents because of their stability to light exposure and inexpensive [2]. Sometimes, dyes are unable to be bonded strongly with fabric fibers and will be lost during the washing process into the water. ...
The most problem in the combination of adsorption and Fenton oxidation processes is the low ability of sorbents to degrade organic pollutants. Therefore, the sorbents need to be modified by adding metal salt compounds, especially those containing iron. In this study, we investigated the use of natural pumice to prepare zeolites with high catalytic properties without adding iron sources. Pumice-based zeolite was prepared through simple hydrothermal alkaline treatment and used to remove methylene blue (MB) from aqueous solution. The characterization results confirmed that the mineral phase of pumice was successfully transformed to GIS-NaP1 zeolite. The maximum value of adsorption capacity increased highly from 7.80 to 35.33 mg/g after the treatment process. Adsorption isotherm showed a better fit to the Langmuir model with a high correlation coefficient value (R2 = 0.999) compared to the Freundlich model (R2 = 0.882). This means the interaction between zeolite and MB followed the assumption of monolayer adsorption on homogeneous surfaces. Interestingly, the synergistic effect of adsorption and Fenton oxidation processes enhanced the ability of zeolite to remove MB with efficiency from 60.92% to 99.99%. Furthermore, zeolite can also be reused several times without reducing its performance significantly after regeneration.
... Nonetheless, the drawbacks of natural dyes, e.g., the lack of hue uniformity, low yield, poor adhesion, and poor fastness characteristics limit its usage in textile production [8]. Despite these limitations, colourists tend to substitute synthetic dyes with natural dyes [9]. Apparently, due to their toxicity, non-biodegradability, and environmental effects, synthetic dyes are being replaced with natural dyes, which could eradicate the problems [10]. ...
Dyes derived from coconut (Cocos nucifera) husk have materialised as an important substitute to synthetic dyes. However, better extraction techniques are needed to leach out the natural colourants from this plant. The influence of sodium hydroxide (NaOH) concentration (0.2 to 0.8 M) and time of extraction (2 to 10 min) on the maximum extraction yield of natural dye from the mesocarp and exocarp of C. nucifera have been studied. The results indicate a significant (p < 0.05) increase in dye yield for both mesocarp and exocarp extracts when using 0.8 M NaOH for 4 min. This study had also investigated the effect of different concentrations of tannic acid as a mordant on dyeing properties and wash fastness of cotton fabrics dyed with the mesocarp and exocarp C. nucifera dyes. The dyeing process of the natural dye was performed by varying the concentrations of tannic acid (2.5%, 5.0%, and 7.5%) at 40 °C for 60 min. Pre-mordanted dyed cotton fabrics showed a deeper colour than unmordanted dyed cotton fabrics. As the concentration of tannic acid increases, the L* value decreases in all pre-mordanted fabrics. Tannic acid as a mordant exhibited better result at 7.5% concentration than the 2.5% and 5.0% concentration. The darkness and shade of the dye from the mesocarp exhibited a better outcome than the exocarp of C. nucifera and confirms that the mordant enhanced the dye hue on cotton fabric. Wash fastness properties of mesocarp dyed cotton fabrics ranged from poor (2) to good (3) depended on the tannic acid concentration used. This work suggests that mesocarp C. nucifera dye can complement synthetic dyes in the dye industries.
... Doğal boyarmadde bitkileri çevre kirliliği oluşturmayan [20], toksik ve kanserojen olmayan yıllık veya iki yıllık bitkilerdir. Hatta hayvansal kökenli boyarmaddelerin bazı özellikleri bitkisel boyarmaddelerden daha üstün olmasına rağmen, son yıllarda kullanılması tercih edilmemiştir. ...
Özet
Günümüzde doğal renklendiriciler gösterdikleri çeşitli antioksidan, antibakteriyal, antimikrobiyal v.b. aktivitelerinden ve bazı sentetik renklendiricilerin insan sağlığı üzerinde olumsuz etkilerinin gün yüzüne çıkmasından beridir ilgi odağı haline gelmişlerdir. Bu çalışmada, doğal renklendiricilerin kaynakları, sınıflandırılmaları ve kimyasal bileşenleri tartışılmıştır.
Abstract
Nowadays natural colourants which have various antioxidant, antibacterial, antimicrobial, etc. activities have been point of interest since the emerged negative effects upon human health of some synthetic colourants. In this study, chemical components, types and sources of natural colourants were discussed.
... yüzyılın ikinci yarısında keşfedilen sentetik boyalardan sonra azalmaya başlamıştır (Cristea and Vilarem, 2006). Sentetik boyaların iyi haslık değerleri sağlarken daha ucuz ve kolay ulaşılabilir olması, geniş renk skalasına sahip olması gibi nedenlerle ön plana çıkmıştır (El-Nagar et al., 2005;Bechtold et al. 2007). Ancak son yıllarda, sürdürülebilirlik, ekolojik ürünler, çevre dostu üretim gibi kavramlar doğal boyalara olan ilgiyi arttırmıştır (Bechtold et al., 2007;Mirjalili et al., 2011). ...
Doğanın insanlara sunduğu renklerin bilinen en eski örneklerini duvar resimlerinde görmekteyiz. Bulunan bu en erken örneklerle (El rezerve baskıları, yaklaşık MÖ 40.000, El Castillo Mağarası, Puente Viesgo, Cantabria Bölgesi, İspanya) başlayan doğal boyarmadde kaynaklarının kullanımı günümüzde de devam etmektedir. 19. yüzyılda sentetik boyaların bulunuşu ve endüstriyel olarak kullanımının başlamasıyla, önemini kaybeden doğal boyalar, 21. yüzyılda doğal, ekolojik, çevre dostu gibi birçok kavramla yeniden hayatımıza girmeye başlamıştır. Bu noktada doğal boyalara olan ilgi ve kullanım alanlarının yaygınlaşmasının yanı sıra yeni uygulama yöntemleri de ortaya çıkmıştır. Bitkilerle ekolojik baskı ve mordan baskı bunların başında gelmektedir. Dünyada birçok sanatçı doğal boyamacılık, doğal pigment yapımı, bitkilerle ekolojik baskı gibi konularda atölye çalışmaları düzenlemekte, geleneksel ve yeni yöntemleri öğretmektedirler. Bilinçli üretici ve bilinçli tüketici yaratmak adına bu atölyeler oldukça faydalı olmaktadır. Doğa ve ekoloji için oldukça önemli olan bu atölye çalışmaları, aynı zamanda ciddi bir gelir kaynağı da sunmaktadır. "Solar Dyeing" olarak bilinen, dilimize "Güneş Işınları ile Boyama" olarak çevrilmesi uygun olan bu yöntem hakkında maalesef yazılı herhangi bir akademik çalışmaya rastlanmamıştır. Doğal boyamacılıkta, kontrol edilmesi gereken ve elde edilmek istenen renge, tona direk etki eden sıcaklık, güneş enerjisinden sağlanmaktadır. Uzun sürelerde (3-10 gün arasında) cam kavanozlar içerisinde yapılan boyama işlemi, bir anlamda soğuk boyamada olduğu gibi zaman üzerinden ilerlemektedir. Yapılan araştırmada güneş ışınlarını daha etkin bir şekilde kullanabilmek için farklı sistemlerin geliştirildiği görülmüştür. Yansıtıcı yüzeyler ile desteklenen boyama alanında, güneş ışınlarından en etkin şekilde faydalanılmaya çalışılmıştır. Geliştirmeye açık olduğu düşünülen bu yöntemin uygulanma şekli, olumlu ve olumsuz yönleri, uygulama alanları araştırılarak, denemeler yapılacaktır. Geleneksel yöntemlerle boyamalar yapılarak, sonuçlar renk ve haslık değerleri açısından karşılaştırılacaktır.
The oldest known examples of the colors that nature offers to people could be seen in murals. The use of natural dyestuff sources, which started with these earliest samples (Resist printings of hands, about 40,000 BC, El Castillo Cave, Puente Viesgo, Cantabria Region, Spain), continues to be used today. With the discovery of synthetic dyes in the 19th century and starting the usage in industries, natural dyes lost their importance but began to re-enter into our lives with many concepts such as natural, ecological and environmentally friendly in the 21st century. At this point, as well as the widespread interest and use of natural dyes, new application methods have emerged. Ecological printing with plants and mordant printing are the leading ones. Many artists in the world are organizing workshops on natural dyeing, natural pigment production, ecological printing with plants and teaching traditional and new
... venture into replacement of natural dyes with synthetic dyes (El-Nagar et al. 2005). Non biodegradable, toxic and environmental challenges of synthetic dyes on textile materials and their consumers made colorists and researchers to turn back to the use of natural dyes that are free from these challenges (Shahid et al. 2012). ...
Bridelia ferruginea B dye was extracted from the bark of the tree using aqueous extraction method. Extracted dye was used to dye cellulosic (cotton) fabric in presence of 5% calcium chloride (CaCl2) or 5% alum (KAl(SO4)2·12H2O) of weight of fabric (o.w.f) as mordant. Fabric dyed without mordant was lighter in hue than metal ion mordanted dyed fabrics. The fabrics dyed in presence of calcium chloride as mordant are of deeper hue than those dyed with alum as mordant. Hence, their dye-uptake and color strength (K/S) are in the same order. K/S value of fabric dyed with alum is 43.71% higher than that without mordant and fabric dyed with calcium chloride has K/S value 51.09% higher than dyed with alum as mordant. CIEL*a*b* coordinate indicator and color space quadrant showed that those dyed fabrics without mordant and with alum as mordant are closer to yellow than red color. Those cellulosic fabrics dyed with calcium chloride as mordant are closer to red than yellow color as confirmed in colour space quadrant. Pre-mordanted dyed fabrics are of deeper color than post-mordanted dyed fabrics than meta-mordanted dyed fabrics than unmordant dyed fabric. Fastness properties of B. ferruginea B dyed cellulosic fabrics ranged from good (3) to excellent (5).
... In addition, it is known that some of the synthetic dyes used in the industry contain carcinogenic substances (Srivastava and Singh, 2019). For these reasons, synthetic dyes cause environmental problems (El-Nagar et al., 2005). Many parts of plants are used in many fields such as food, health, textile and cosmetics especially as biotechnologically (Ercisli et al., 2008;Cüce et al., 2017b) In the last quarter century, the interest in natural dyestuffs has increased in terms of eliminating all these problems and in terms of sustainability (Merdan et al., 2014;Dayioğlu et al., 2016). ...
... Natural dyes cause less enviromental and wastewater problems. Compared to some synthetic dyes, they are more environmentally friendly (El-Nagar et al. 2005;Mirjalili, Nazarpoor, and Karimi 2011). The most common yellow natural dyes have been used up to the end of 19 th century in the paintings as lake pigments and in the textiles as flavonoid derivatives that are mordant dyes (McNab et al. 2009). ...
In this study, the silk fabrics mordanted at the rates of 1%, 2%, 3%, 4%, 6%, 9%, 12%, 14%, 18%, 21%, 24%, 27%, 30%, 33% and 36% of alum (KAl(SO4)2.12H2O) were separately dyed with chrysin, quercetin dihydrate, 7,8-dihydroxyflavone and naringenin flavonoids. The CIEL*a*b* color values of the performed dyeings were measured and compared with each other. According to the results of the color measurement, the dyeings obtained using the mordant of 6% alum showed the best color values. The bonds relating to the amino acids present in Bombyx mori silk were characterized by FTIR. Also, the binding to the fibroin protein via Al-O and Al-N bonds of Al (coming from alum mordant) was determined. The amino acids including of pure silk were specified by ¹³C CP/MAS NMR. The coordination numbers of Al (III) ions in the complexes formed among the silk fibroin-mordant-dye were determined by ²⁷Al MAS NMR.
... Six known compounds were identified by comparing their spectral data with values reported in the literature as ellagic acid, 3, 3',4'tri-O-methylellagic acid, ethyl brevifolin carboxylate, urolic acid, maslinic acid, and daucosterol (Wang et al., 2010;Mahmoud et al., 1994). According to their sources, dyes are divided into two classes as natural and synthetic (Nagar et al., 2005). Dyes from liquids in which they are completely or at least partially soluble are applied to different materials like textiles, leather, paper, hair, food, cells at different temperatures and time (Zollinger, 2004;Guler and Benli, 2017). ...
Natural dyes and especially hematoxylin, which is herbal, are widely used in staining tissues. The aim of this study is to
evaluate the staining status of different tissues taken from rats with pomegranate flower extract. For this reason, 2 Wistar
albino rats, one male and one female, were used as stain biomaterial. A histological follow up procedure was applied to the
lung, kidney, liver, and heart tissue samples taken from the rats and the unstained preparates of these tissues were prepared.
As the source of the dye, the dry flowers of Punica granatum (PG) obtained from local markets of Kayseri were used. Each
tissue sample underwent the same staining procedure with the same temperature, duration, and dye solution. Before and after
the staining procedure, ×40 images of the tissue preparates were taken using a light microscope. Generally, different tones
of staining were observed in the nuclei and cytoplasms of all cells and epithelium cells. Staining in parts specific to each
tissue occurred. For example, there were light stains on the glomerular cells and the Bowman capsule in the kidney tissue
Differences in staining can only be explained by molecular diversity differences in tissue. However, in order to improve the
initial staining results obtained in this study, it is possible that working with different temperatures, pH values, mordant substances, and dye that the dye molecules in the extract will provide more vivid colors with different molecules in the tissues.
... Thus, these phenolic groups react with caustic soda (NaOH) and form more soluble salts in water. Indeed, in an alkaline aqueous medium, it will have an acid-base reaction between the hydroxyl groups ( El-Nagar et al., 2005) of the polyphenol (Example: Quercetin) and the caustic soda for obtaining salts which are more soluble in water than the departure polyphenols ( Khaliq et al., 2015;Gomez-Alonso et al., 2007). This reaction is represented by figure 5. ...
The purpose of this work envisages developing an eco-friendly technology by the application of renewable biomaterials as a source of natural colorants for dyeing textile substrates. In this study, natural dyeing extracts for textile fibres were obtained from grape pomace, a by-product generated in the winemaking process, and from olive trees pruning wastes, a native species from the Mediterranean basin. The wool fabrics were dyed with different extracts (acidic, aqueous and alkali extracts). Olive leaves extracts gave greenish shades and grape pomace extracts gave brownish shades. The wash and rubbing fastnesses of dyed wool samples were found to be within the range of 4 to 5 means fairly good to very good level. The ultraviolet protective properties of the textiles fabrics dyed by grape pomace and olive leaves aqueous extract were also investigated.
... Textile dyeing processing industry is one of the significant environmental polluters by using synthetic dyes in comparison with natural dyes [10,11]. ...
... Synthetic colorants in view of cheaper price, wide range of colors, and considerable improved fastness properties are extensively used in textile industries for dyeing of different textile materials (El-Nagar et al. 2005;. However, recent research have shown that some of the azo and benzidine based synthetic dyes produces some toxic, allergic, and carcinogenic secondary degradation byproducts (aromatic amines). ...
In this study, wool fibers are dyed with a natural colorant extracted from walnut bark in presence and absence of mordants. The effect of aluminum sulfate, ferrous sulfate, and stannous chloride mordants on colorimetric and fastness properties of wool fibers was investigated. Juglone was identified as the main coloring component in walnut bark extract by UV visible and FTIR spectroscopic techniques. The results showed that pretreatment with metallic mordants substantially improved the colorimetric and fastness properties of wool fibers dyed with walnut bark extract. Ferrous sulfate and stannous chloride mordanted wool fibers shows best results than potassium aluminum sulfate mordanted and unmordanted wool fibers. This is ascribed due to strong chelating power of ferrous sulfate and stannous chloride mordants.
... However, with the discovery of advantageous synthetic dyes from coal tar and petrochemical sources use of natural colorants was pushed aside in the later part of 1900 century (Bechtold et al. 2003;Shabbir et al. 2016). Synthetic colorants were appreciated in the market place in view of their low cost, wider range of colors, and better color fastness properties than their natural counterparts (El-Nagar et al. 2005;Iqbal et al. 2008). Researchers have recently identified that most of the azo-based synthetic dyes produce toxic chemicals which have serious ecological and human health concerns (Islam et al. 2014;Melgoza et al. 2004). ...
The present article focuses on the effect of different combinations of metal mordants on color characteristics and fastness properties of natural dye extracted from Juglan regia L bark powder. The influence of different types of mordant combinations such as alum + ferrous sulphate, alum + stannous chloride, ferrous sulphate + stannous chloride, and alum + ferrous sulphate + stannous chloride on color parameters has been investigated in terms of CIELab (L*, a*, b*, c*, and h°) and K/S values. The fastness properties with respect to light, washing, and crocking of developed shades were determined according to ISO and AATCC test methods. Based on the experimental results, it has been found that 96 shades with novel and fashionable hues were produced by the use of these metal salt combinations. It was also found that all mordanted samples had satisfactory light and wash fastness ratings. Dry rub fastness was found relatively better than wet rub fastness.
... Nowadays, textile dyeing processing industry is one of the major environmental polluters; synthetic dyes have been in use globally in textile industries due to their availability, lower prices and wider ranges of bright shades with considerably improved color fastness properties in comparison with natural dyes [13]. But according to the application of synthetic dyes, much water effluent generated during textile dyeing would pollute the environment as it contains a heavy load of chemicals, where it is estimated that 10-15% of the dye is lost in the effluent during the dyeing process [14]. ...
... In recent years, much research work has been directed towards the chemical modification of cotton which involves the introduction of cationic sites (Seong & Ko, 1998). This is due to the environmental problems associated with dyeing processes, especially reactive and direct dyes which require considerable amounts of salts and alkali (El-Nagar et al., 2005). ...
Cationization of cotton is an effective tool that solves environmental problems by using vat dyes. In this research, the cationizing efficiency of Cibafix WFF and PrefixK are studied to replace toxic conventional redox agents with ecofriendly alternatives. It is found to be a better method when compared with the conventional and existing method of vat dyeing of cotton. Conditions, such as concentration of cationizing agents, time, temperature and pH, are optimized. Such conditions show better color strength when compared with conventional dyeing methods. The effect of cationization on color strength and fastness is observed, and show higher value in both light and dark shades. The cationized samples show comparable quality and are cheaper in cost when compared with the normal vat dyeing method. Cationization of cotton with Cibafix WFF is found to be a successfully and commercially viable process.
... Under normal cultivation, cotton [2] may be exposed to significant quantities of chemical contaminants, including herbicides, pesticides, defoliants and fertilizers. Additional chemicals may also be added during the manufacture of conventional cotton into clothing and other commercial goods. ...
... where R is reflectance values measured in %. The treated and untreated samples were measured for their colour parameters e.g., L (lightness), a (redgreen) and b (yellow-blue) colour components in accordance to the CIE-Lab colour measuring system (10,12,13) . ...
Cassia fistula bark is a good source of natural dye containing anthraquinone as a coloring component that
imparts reddish brown color on cotton fabric. The bark of Amaltas (cassia fistula L.) was ground into fine particles and exposed to UV radiation for one hour at 254nm wavelength. The extracts were obtained from control and irradiated powder. Different media such as water, alum and ethanol were used to optimize the extraction and dyeing conditions. Finally the dyed samples were investigated in CIE Lab system to get ΔL, Δa, Δb, and colour strength values. Fastness properties such as washing fastness, rubbing fastness, light fastness were also studied in order to evaluate the effect of UV radiation on the dye-ability of cotton fabric with the extracts of cassia fistula powder as natural dye source
... However, recently the concern for the environment has created an increasing demand for natural dyes, which are friendlier to the environment as compared to synthetic dyes. 2 Although there are several types of radiations, e.g. ultraviolet (UV) and visible 3,4 , the treatment of fibres with UV radiations affects the colouration. ...
Natural dye containing Lawsone that imparts yellowish-green colour on to the cotton fabric has been extracted using water, alum and methanol from non-irradiated and irradiated henna powder through UV source. The effect of treatment time, temperature and salt concentration on the dyeing of cotton fabric has been studied using CIELab system for the optimization of dyeing conditions. Different mordants, such as copper sulphate and ferrous sulphate, have been employed for the improvement in colour fastness properties of the irradiated dyed cotton fabrics. It is observed that the UV radiation not only enhances the colour strength of dye on cotton fabric but also improves the fastness properties of pre-irradiated cotton fabrics.
... This can be explained by the fact that the compounds that confer color are predominantly phenols which are easily deprotonated by NaOH, increasing their solubility compared to the aqueous solution. The same result has been reported in the literature (El-Nagar et al., 2005). ...
... Fig. 1.1 also revealed that the recovery of total phenolic content increases with sodium hydroxide concentration due to the increase in the dissociation's degree and in turn; the fraction of phenolates (phenoxide anions) increases in strongly alkaline solution. It can be attributed to acidic hydroxyl group (El-Nagar, Sanad, Mohamed, & Ramadan, 2005), which reacts with alkali and form salt which is more soluble in water. ...
... Coloring is one of the most delightful arts and the most important branches of manufacture; before the mid-19 th century professional dyers of fine silks and woolens had to rely on such homely substances as dried insects, roots and leaves of plants, concluding that natural dyes are an education in ecology and ethics, where no other dyes provide a better opportunity teaching how to protect and respect the environment (Siva, 2007). Nowadays, textile dyeing processing industry is one of the major environmental polluters; synthetic dyes have been in use globally in textile industries due to their availability, lower prices and wider ranges of bright shades with considerably improved color fastness properties in comparison with natural dyes (El-Nagar et al., 2005). According to the application of synthetic dyes, much water effluent generated during textile dyeing would pollute the environment as it contains a heavy load of chemicals, where it is estimated that 10 to 15% of the dye is lost in the effluent during the dyeing process (Iqbal and Ashiq, 2007). ...
Dyeing is one of the most delightful textile arts which are an important branch in fashion design. Natural dye is a fascinating phenomenon that enticed researchers to their chemistry and production of fantastic novel hues to explore the point that no other dyes provide a better opportunity teaching how to protect and respect the environment. In this research, silk fabric was dyed by a mixture of different percentages of cochineal, curcumin and indigo powders in water-acetone co-solvent to possess an ecological acceptable for dye extraction. Extraction and dyeing processes were carried out together in one step at different pH values using sonic energy regarding the promising technique in saving energy. Silk dyeing exhibited a variety of shades according to the evaluated colorimetric data which could be attributed to their resonating structures, where the pH values play important parameter in this phenomenon and control the adsorption capacity of dyes onto silk. So, this research give the chance to produce different hues from the traditional natural dyes to improve the natural dyeing cultural heritage to meet the environmental future demands technology of high quality fantastic dyed patterns through an economical point of view.
Son yıllarda artan çevresel sorunlar ve ülkelerin bu konudaki yasal düzenlemelerinden dolayı kağıt endüstrisinde kullanılacak kimyasal maddelerinin çevre dostu olması önem kazanmıştır. 19. yüzyılın ikinci yarısından sonra sentetik boyaların keşfi ile doğal boyalar atıl kalmıştır. Günümüzde artan çevre sorunlarına, doğal boyarmaddelerin kullanımı pozitif yönde katkı sağlayacaktır. İnsanların, hayatlarına kolaylık ve zenginlik getirmesi için ağaç kabuklarından çeşitli ürünleri yapması çok eskilere dayanan geleneklerindendir. Kabuklardan, şişe mantarı, tanenli maddeler, boyarmaddeler, sakız, reçine, lateks, gıda maddeleri, aromatik maddeler, olta ve ok zehirleri ve tıpta kullanılan bazı maddeler elde edilebilmiştir. Kızılçam kabuğu ürün üretme anlamında ülkemiz için en önemli ağaç türlerinden bir tanesidir. Kızılçam ağacı Türkiye ve hatta Dünya için önemli bir ağaç türüdür ve ülkemizde yaklaşık altı milyon hektarlık bir yayılış alanına sahiptir. Ormanda kesimden sonra kızılçam ağacı kabukları artık olarak bırakılmaktadır. Değerlendirilmesi durumunda önemli bir biyokütledir. Doğal boyarmadde kullanımı için ormanlardan kaldırılması orman yangınlarını önlemede de önemlidir. Bu çalışmada kızılçam kabuğundan üretilmiş doğal boyarmaddenin kullanım olanaklarına, deneysel çalışmalara değinilmiştir. Bu çalışmanın amacı; doğal boyarmadde kullanım olanağı olan kızılçam kabuğundan üretilmiş doğal boyarmaddelerin kullanılabilirliğinin incelenmesi ve geniş bir özetinin çıkarılmasıdır. Bu çalışma kızılçam kabuğundan boyarmadde üretimi ve odun hamuruna bu boyarmaddenin tutulumu konusunu çalışan bilim insanlarına katkı sunacağı düşünülmektedir. Yapılan bu çalışma daha önceki çalışmaların derlemesi olup bundan sonraki çalışmalara kaynak teşkil edecek niteliktedir.
The present study utilizes natural dyestuffs which would not contribute to environmental pollution and undertaken to explore promising approach to reduce costs of dye process. The natural dyes of henna and onion skin were used to dye different fabric materials, i.e. 100 % cotton, 100 % polyester and 35 % cotton / 65 % polyester blend. The low temperature 30 °C and the high temperature 100 °C under closed dyeing system were applied in this study. The results indicated that, using the natural dyes (henna and onion skin) with the previously mentioned fabrics under the low temperature (30° C) resulted in an increase in fabric strength of the 100 % cotton fabric and the 35 % cotton / 65 % polyester blend, while no change in fabric strength of the 100 % polyester material. Thus it appeared that using these natural dyes would not cause any deterioration in fabric strength. On the other hand, the fabric elongation was not affected by the dyeing process. The results showed that the shrinkage values of fabrics dyed with henna were generally lower than the corresponding values of fabrics dyed with onion skin. All fabric materials under this study when dyed with henna and onion skin, revealed higher fastness to light and wash, lower fastness for alkali and acid perspiration. Finally, it was observed that using high temperature and closed dyeing system was not suitable for dyeing these kinds of fabrics with henna and onion skin dyes.
The manufacture of regenerated cellulose-based fibers for better mechanical and comfort qualities was stimulated by the rising demand for cotton and the low production rate needed to meet global demands. Modal-cotton blend provides better tensile and moisture management properties. The present work has been designed to sketch out the scope of increased dye fixation or dye uptake opportunity onto the blends. Cotton-modal blend was dyed with mahogany leaf extract dyes avoiding mordant. The higher wash fastness rating 4/5, 5 along with the FTIR characteristic bands around 1190-1210 cm−1 created attention for the confirmation of dye-fibre bonding. But as modal is a regenerated cellulosic fibre, there was a suspect of uneven fixation because of dual way dye penetration options inside the fibre: direct bonding with cotton cellulose and dye penetration into swollen modal fibre through segmental mobility theory. Fortunately the uniformity of shade was affirmed by the determination of evenness through random CMC DE and K/S values at distinguished parts of the same sample. Mordantless mahogany dye fixation on cotton-modal blend was found even at the elevated dyeing temperature of 130 °C. The detailed CIE Lab data explored the close symmetry and uniformity of the dyeing outcomes of the blend.
Suitability of apple tree bark as a natural source for cotton dyeing. The study of dyeing cotton fabric with apple bark extract with the use of mortars - inorganic aluminum, tin, iron and copper salts, moreover oxalic acid and without mortar. The color of the fabric was determined using the CIE L*a*b* system. The result was a yellow color of varying shades, ranging from lemon to warm, intense yellow. In the case of iron and copper, a significantly different color was obtained, dark khaki and rusty brown respectively. Color fastness tests were carried out using hot water, mineral acid, mild and hot washing, dry cleaning and natural exposure to sunlight. It has been found to have excellent resistance to dry cleaning and good to a gentle wash. Dyed fabric showed the weakest resistance to sunlight and to mineral acid.
This article is about natural dyes for multifunctional cotton coloration and finishing. Cotton, the king of natural fibers,
demands coloring, antimicrobial, and UV protection, without damaging cotton's inherent comfort. Therefore, natural dyeing
has become an essential requirement in the coloration and finishing of cotton fabrics because of its natural and environmental properties that do not harm people. Furthermore, most natural dyes also have inherently antimicrobial and UV protection properties. They are made from various microorganisms and plant and marine algae parts that contain pigments like tannin, flavonoids, and quinonoid. Here we review the scientific research on printing, antimicrobial finishing, and UV protection of cotton fabrics using natural dyes.
The aim of this research was to identify optimum values of the colorfastness properties of sustainable dyes on cotton fabrics. Sustainable dyes are ecofriendly, biodegradable, economical and easily attainable from natural sources. The findings of this research established that good colourfastness properties of cellulosic fibres could be obtained using sustainable natural dyes. Experiments were carried out on 100% cotton voile fabrics of plain weave using four types of natural dyes: strawberry dye, beetroot dye, rose dye and China rose dye. Strawberry dye reacted with the cellulose of the cotton in an alkaline condition to form a stable covalent bond amid the dye and cellulose and showed outstanding colour fastness properties. The required experiments were conducted using the standard specified by ASTM and AATCC as stated in this paper. The colour strength properties, colour intensity properties, colour absorbency properties and colorfastness properties were investigated using a reflectance spectrophotometer and "Agilent Cary 630 FTIR Instrument" as stated in this paper. A sample dyeing machine-"Pad Dye Pad Steam" was used in this research to dye the cotton fabrics with sustainable natural dyes. The colorfastness properties were investigated using grey scale test results, and the colour strength and absorbency properties were tested using the spectrophotometer and FTIR instruments. The peak values of the FTIR instrument guaranteed the existence of the colourant or chromophore present in the dyestuffs, and exposed the best colourfastness properties. The findings of this research could be beneficial to personnel involved in textile industries who are in charge of dyeing cotton fabrics with natural dyes as well as controlling their colourfastness properties and colour intensity properties.
An important concern has been reached a growing interest in natural dyes in the textile dyeing industry for coloring fabrics due to growing environmental consciousness of preventing toxic synthetic dyes. Moreover, the use of metallic mordants does not make them entirely eco-friendly. Being aware of this, this report examines cotton knit fabric dyeing with natural mordants with dyes derived from onion skin executed using aqueous boiling technique. Diverse mordants, e.g., alum, ferrous sulphate, iron water, myrobalan, eucalyptus bark, and their combinations on cotton knit fabrics were used for pre-mordanting and together mordanting procedures. Several techniques and different types of equipment were used to measure various results. As a result, the mordanting techniques were reported to impact the outcomes of the dyeing procedure. That diverse mordants and mordanting techniques influenced the colour values produced a wide variety of gentle colors; thus, intermixing of natural and synthetic mordant gave the best result in together mordantation. Also, the pre-mordanting method gave averagely better results and dyeing properties than together mordanting, but eucalyptus gave the best results in together mordantation. Fading was found a little dissatisfactory in washing in case of natural mordants, yet staining properties were quite impressive. For other dyeing properties, satisfactory results were found for both natural and synthetic mordants. Their intermixing also contributed better results. Hence, it was evident that eucalyptus bark might be used as a suitable natural mordant for onion skin dyeing since eucalyptus showed the best result as an individual mordant or intermixing with synthetic mordant.
Since the second half of the 19th century, the world of textile production was radically changed both in terms of esthetics and of the performances leading to industrial products whose chemical properties were totally unknown and unexplored. Stage costumes are typical examples of multi-material art objects where different natural and synthetic materials were used to fulfil specific purposes. This research was performed in the framework of a diagnostic and restoration campaign of dresses of two Federico Fellini’s movies (“Il Casanova” and “Roma”). For the characterization of the textile fibers, Attenuated Total Reflection Fourier Transform Infrared Spectroscopy (ATR-FTIR) and Pyrolysis Gas Chromatography coupled with Mass Spectrometry (Py-GC/MS) were employed. The structure of the metallic threads was investigated by Scanning Electron Microscopy coupled with Energy-Dispersive X-ray Spectroscopy (SEM-EDX). Dye identification was carried out by High Performance Liquid Chromatography coupled with Diode Array Detector and mass spectrometry (HPLC-DAD, HPLC-ESI-Q-ToF). The analytical approach adopted allowed us to fully characterize the costumes composed of natural, synthetic and artificial fibers dyed with complex mixtures of last generation synthetic dyes. The results collected were fundamental to fine-tune an effective restoration aimed at minimizing the damages due to ageing, inaccurate home-made restoration interventions, or poor conservation conditions.
Dyeing cotton with direct dye at room temperature, reduced time and low concentration salt. The resulted samples has high fastness and colour strength.
Fresh neem leaves (Azadirachta indica A. Juss) consist of quercetin (flavonoid) compound, responsible for yellow colour as a natural dye. The study investigated the variable optimization in fresh neem leaf extraction process and its application. The optimization was conducted using response surface methodology (RSM) and ANOVA test. The coefficients of determination (R2) were generalized at 96.46 and 96.39 % for optimizing extraction process and application process parameter of natural dyes from neem leaves, respectively. The optimum variables for the extraction process were obtained at 50 % w/v feed-solvent ratio, the temperature of 80 ºC and extraction duration of 80 min with the response concentration of 46.19 g/L. Furthermore, the optimum variable on the application of natural dyes from neem leaves was recorded when alum was applied as fixator as much as 14.09 g/L and Turkish red oil (TRO) as mordant at 11.16 g/L resulted the response of 0 % on the degree of faded.
Meningkatnya kesadaran di kalangan masyarakat tentang efek bahaya dari penggunaan zat pewarna sintetis membuat eksplorasi zat pewarna alami terus dilakukan. Banyak pewarna yang dihasilkan dari tumbuhan dan digunakan untuk pewarnaan tekstil. Penelitian dilakukan untuk mencari potensi dari daun harendong (Melastoma malabathricum) dalam menghasilkan pewarna alami untuk kain katun. Optimalisasi pewarnaan kain dilakukan dengan penambahan mordan berupa tawas [KAl(SO4)2.I2H2O], kapur sirih (Ca(OH)2), dan tunjung (FeSO4) saat proses fiksasi pada kain katun. Kain katun yang telah diwarnai diidentifikasi warnanya menggunakan RGB (Red Green Blue) Color Chart Reader. Kain katun yang diwarnai dengan ekstrak daun harendong menghasilkan warna Banana (#E3CF57). Pemberian mordan saat fiksasi berpengaruh terhadap warna kain. Kain yang difiksasi menggunakan tawas berwarna Khaki 1 (#FFF68F), sedangkan yang difiksasi menggunakan kapur sirih berwarna Lightgoldenrod 1 (#FFEC8B) dan kain yang difiksasi menggunakan tunjung berwarna Sgi Gray 36 (#5B5B5B). Penambahan mordan juga memberikan pengaruh baik terhadap ketahanan luntur warna pada kain katun akibat pengaruh pencucian dan paparan sinar matahari. Daun harendong berpotensi baik dalam mewarnai kain katun.
The present study utilizes natural dyestuffs which would not contribute to environmental pollution and undertaken to explore promising approach to reduce costs of dye process. The natural dyes of henna and onion skin were used to dye different fabric materials, i.e. 100% cotton, 100% polyester and 35% cotton/65% polyester blend. The low temperature 30 °C and the high temperature 100 °C under closed dyeing system were applied in this study. The results indicated that, using the natural dyes (henna and onion skin) with the previously mentioned fabrics under the low temperature (30° C) resulted in an increase in fabric strength of the 100% cotton fabric and the 35% cotton/65% polyester blend, while no change in fabric strength of the 100% polyester material. Thus it appeared that using these natural dyes would not cause any deterioration in fabric strength. On the other hand, the fabric elongation was not affected by the dyeing process. The results showed that the shrinkage values of fabrics dyed with henna were generally lower than the corresponding values of fabrics dyed with onion skin. All fabric materials under this study when dyed with henna and onion skin, revealed higher fastness to light and wash, lower fastness for alkali and acid perspiration. Finally, it was observed that using high temperature and closed dyeing system was not suitable for dyeing these kinds of fabrics with henna and onion skin dyes.
This paper introduces an analytical method for identifying the colour base extracted from the walnut shell (Juglans regia L.) which is based on the extraction of colourant from walnut shell through a solvent using Soxhlet apparatus. Here, the main colour bases of samples were isolated and analyzed by column chromatography, thin layer chromatography, infrared, nuclear magnetic resonance and mass spectrometry. The method easily allows the identification of several colour bases by detecting the molecular structure and finally the separation of chemical structures from this plant. The absorbability of the extracted dye using ethanol solvent has been compared to that of the dye from the raw plant in order to determine the dyeing efficiency rate through dyeing silk fibers. The results show that the exhaustion rate for the extracted dye increases by 54 % compared to the raw dye. This per self leads to a considerable decrease in the
amount of the extracted dye used to reach the same desired results.
Instrumental light aging is one of the most important tools for restoration and conservation of historical textiles. It used in testing stability of conservation materials, in addition to its lightening effect during the presentation in the museums. Light fading is an important tool for preparing the aged textile and other polymeric samples especially for archaeological conservation applications. Many fadometers do not give homogeneous exposure for all sample’s areas. This work studies the color changes of silk fabric dyed with turmeric (Curcuma longa L.) mordanted with alum or ferric sulfate. Color change was studied for the exposure periods ranged from five to hundred hours. Three positions of different irradiance levels were measured on the same sample namely (bottom, middle and upper). Individual color change for each position was recorded and studied. The results showed that there is non-homogeneous irradiance distribution due to different positions in fadometer or mordant used.
Indigo carmine can be used as a source of blue dye for wool and hair dyeing. The option to use indigo carmine in combination with other natural dyes in a one-bath procedure as a hybrid dyeing concept is of interest both for natural dyeing and for coloration of hair. The present study shows that indigo carmine dyeing on wool exhibits the substantial sorption in the range of pH 4–5 and temperature between 40 and 60°C. Experiments with human hair samples indicate that the experiments on wool can serve as a model that can be applied for hair dyeing. Comparisons of the energy, water and chemical consumption between two-bath dyeing with indigo and natural dyes separately and a one-bath dyeing using indigo carmine together with other natural dyes demonstrates the advantages of the one-bath hybrid dyeing concept.
Polyester fibers are hydrophobic in nature; most of the successful preparations such as dyeing, printing, and finishing are based on wet treatments. The plasma treatments for polyester textile surfaces using low-pressure pseudo-discharge in nitrogen as a working gas are discussed in this work. Different plasma parameters, e.g., pressures of 0.06, 0.1, and 0.2 torr; different times (15—600 s); and different currents (1—6 mA), are applied on textile samples in nitrogen plasma. The wetability of the treated specimens was increased by increasing either the electric current or the time at the treatment pressure. The plasma treatment of the polyester fabrics improved for their hygroscopicity and in turn their performances during the dyeing with disperse dye. The optimum exposuring conditions for high water absorbance and best color (expressed as the lightness (L), red-green (a), and yellow-blue (b) coordinates with the CIE Lab color measuring system) were exposure time (15 s), pressure (0.1 torr), and electric current (5 mA). Meanwhile the exposed samples showed no significant deterioration for their mechanical properties expressed as tensile strength and elongation percent, and the results were proved by the examination of the treated samples using a scanning electron microscope.
Increasing environmental awareness has persuaded some of the major Asian countries to reassess the feasibility of natural colorants. As one of the most agriculturally rich regions of the world, the emphasis has been on finding new colour sources which have the potential to yield high-quality dyes. A detailed programme of research and development into the capabilities of natural dyes is of vital importance. A case study of work carried out at Karachi University, Pakistan, is quoted as an example.
This revised edition of a standard work has been slightly abridged, largely by the omission of outdated matter (5th edition, 1975, xii + 709 pages--see abstract 1975/9540). The earlier chapters, as in the previous edition, deal with natural and synthetic fibres (structure, basic chemistry, properties), with attention to processes that precede dyeing (scouring and bleaching) and to developments in shrink-resistant finishes, fluorescent brighteners, and new types of dyeing machines. The ensuing chapters cover the general theory of dyeing and the classification, manufacture and application of the whole range of dyes, with detailed instruction on methods currently in use. Additions have been made to the final two chapters on testing dyed materials and on colour. An appendix gives miscellaneous tabulated data and conversion factors; there are name, dye, and general indexes.
This book, comprehensively illustrated by a very large number of pictures and diagrams, provides detailed information and instruction on various forms of hand spinning and weaving and on the home dyeing of yarns for use in craft work. Individual chapters are devoted, respectively, to card weaving and to the Inkle, Hopi belt, backstrap, Navajo and treadle looms. Other chapters cover methods of finishing hand-woven fabrics, yarn spinning, hand dyeing, design and colour, marketing craft-produced products, and suppliers of fibres, yarns, equipment, books and other items. An appendix contains a glossary of terminology, a recommended reading list, and a subject index.
NH3 and NaOH/NH3 treated cotton fabrics are processed with hot water at 100 and 130°C, and excellent shrink resistance is obtained with the processing. The crystallite form is transformed from cellulose III to cellulose I. Crystallinity decreased by the NH3 treatment increases a little after hot water processing and washing shrinkage is consider ably controlled. Although the dyeing rate decreases with the NH3 treatment, it increases a little with subsequent hot water processing. In contrast, equilibrium dye uptake de creases with the processing. The mechanical properties of the processed fabrics are evaluated by means of KES shear behavior (G, 2HG) and bending hysteresis (B, 2HB). G and 2HG decreased by NH3 and NaOH/NH3 show almost no change after hot water processing, while B and 2HB, especially the latter, decrease considerably with the hot water processing after treatment with NH3 and NaOH/NH 3.
An empirical method for determining the crystallinity of native cellulose was studied with an x-ray diffractometer using the focusing and transmission techniques. The influence of fluctuations in the primary radiation and in the counting and recording processes have been determined. The intensity of the 002 interference and the amor phous scatter at 2θ = 18° was measured. The percent crystalline material in the total cellulose was expressed by an x-ray "crystallinity index." This was done for cotton cellulose decrystallized with aqueous solutions containing from 70% to nominally 100% ethylamine. The x-ray "crystallinity index" was correlated with acid hydrolysis crys tallinity, moisture regain, density, leveling-off degree of polymerization values, and infrared absorbance values for each sample. The results indicate that the crystallinity index is a time-saving empirical measure of relative crystallinity. The precision of the crystallinity index in terms of the several crystallinity criteria is given. Based on over 40 samples for which acid hydrolysis crystallinity values were available, the standard error was 6.5%.
At equal levels of performance, activated (TAED) and catalytic (Mn-TMTACN) laundry bleaching can differ considerably in terms of the concomitant damage to fibres and dyes. To quantify this damage, differently dyed cotton fabrics, and a representative set of eight vat dyes and CI Reactive Brown 7 were used. It is shown that dye fading and fibre degradation are dye-specific and are both highly coupled phenomena. The interpretation of the damage data is based on dye chemistry, reflectance spectroscopy (UV/VIS and NIR) and EPR measurements. Whereas compelling evidence for a genuine catalytic cycle with the quoted manganese complex is lacking, a possible catalytic role of the dyes is proposed. The dramatic green shift resulting from the catalytic bleaching of Cl Vat Blue 4 is explained in detail. The corresponding oxidation is reversible and possibly useful as a fibre damage indicator.
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