Cotton picking, silk cocoon rearing and sorting, animal hair shredding is preliminary to ginning, spinning spinning can be accomplished even today without the aid of any tool. Even today women of Munda tribe Bihar use their thigh for spinnig the tussar yarn information based on field observation.
Other processes like carding, weaving, finishing are also technology based and have been practiced since ancient times. While dealing with the decorations which are done on yarn before weaving, this chapter will discuss the popular traditions of this technique prevalent in the country highlighting the regional character. The discussions in this chapter will be around the patola, ikat techniques of Gujarat, Orissa, Andhra Pradesh.
This chapter will confine discussions to the techniques of decorations employed while weaving in different materials, styles and regions. Popularly known as brocaded fabric, these are intricate woven designs. There are several technologies employed for weaving of the decoration. Traditionally identified as Indian patterned cloth, several indigenous technologies were employed for making these silks, cottons, woolens; replenished with similar materials and zari.
Some of these technologies still continue to be practiced at the regional level in remote villages, some had disappeared and have been revived through concerted efforts and some are only available as historical references. Technologies of Paithani weaving, Kanchipuram weaving, Banaras weaving, Molkapuram weaving, Jamdani weaving, Kani shawl weaving, are some of the examples. Insertion of a particular design involved a specific kind of weaving.. Shri Shahjahan Ansari, Shri Babu are few of the weavers ,who have been bestowed with the national award for commendable work of revival of traditional technologies of weaving.
Banaras weaving has various motifs known as tulip circa , irises circa , mehrab circa , the weaver Shri Anwar Ahmed a traditional family from Varanasi weavers who revived these technologies was recently awarded a national award. The award was bestowed on Shri Anwar Ahmad for recapturing a level of technical and visual quality not seen in the Indian patterned silks since the 19th century. The main technical distinction in this group is that the decorative designs are inserted at the time of weaving.
The discussions in this chapter will proceed according to the regional variations of practices of woven decorations, highlighting specifically the device used for inserting the extra yarn while weaving, the loom employed for weaving, in several materials of silk, cotton, wool and jari. The first part will discuss surface decorations done with the yarn, fabric, beads, stones etc, falling in the group of embroidery and applique work.
Several regional styles of embroidery are continuing from the historic times. Joining or stitching together two pieces was the first intercept of the primitive tool technology towards a civilized life style. The most important tool this process requires is a needle that could pierce to make a hole on the surface and then pass a thread through.
The earliest needles were perhaps the notched bone hooks which could serve the dual purpose of piercing and lifting the thread through the hole, a bone tool similar to the crochet needle of today. Slowly these hooks got the pointed sharp edge on one end and a hole on the other end. Several tools were required for stitching animal skin, skeins.
The evidence of the first needle is found from the Mesolithic times onwards. Harappans invented the needle with eye at the pointed end, as is used in the sewing machines. This needle is used even today for the purpose of embroidery. This single tool with a large variation of techniques has given several styles for the decoration of the textiles. The second part will discuss the fabric decoration with the dyes and colours. They consisted of fugitive stains from berries, blossoms, barks and roots.
They were early examples of so called direct dyes ,i. More sophisticated dyes were developed in later times. The process of mordant dyeing was known in the ancient city of Mohenjo-Daro by about BC. Cave I of Ajanta caves belonging to 6th-7th century AD shows some women wearing simple dotted tie dye patterned bodice. The process of dyeing,mordant dyeing and tie dye are basically the same since antiquity. But just as the industrial revolution brought a change in the weaving technology, the introduction of chemicals for dyeing and bleaching in late 19th century brought swift changes in these processes The thumb nail and thread remained the basic tools for tying.
Some times metal or ivory tube were used to pass the thread for tying. This facilitated its winding around the fabric Crill The printing was done on the fabric mainly with the aid of wooden blocks. The colours were also applied on the fabrics with the help of the kalam or brush. The fabrics ornated with these styles known as kalamkari, pichchavai, mata ni pachedi ,pabuji ka phad were used as the backdrop curtains in the temples and shrines or were the living shrines themselves.
These continued to exist as regional traditions under the religious patronage since historic times. The fabulous tradition of the use of the vegetable colours in the historic periods is now being resurrected and revived for global trade because of its eco-friendly nature. The preparation of the vegetable dyes and other colours and their application in the decoration of the fabrics involves several technologies.
These will be elaborately discussed here. After the independence there has been a concerted effort at various levels in India to revive the fabrics based on the traditional hand technologies. The revival is not only done not only for a sentimental value but also for the commercial purpose. So far as textiles are concerned, India has surpassed all other countries in manufacture of the fabrics based on the hand skills, which have been practiced since the historic times. Several of the revival projects have become success stories for the global market. This chapter will focus on the resurgence and resurrection of the textile technology in the new millenium.
It is visualised that the final document, which will take the shape of a published text of about pages, shall take a minimum of 18 months to complete. The work will include relevant maps, photographs and other illustrations. Chandra ,Moti. Indian costumes and textiles from the eighth to the 12th century, Jouranal of Indian textile history,vol. Jain , Jyotindra and Aggarwal,A. Nabholz-Kartaschoff, M. Ramaswamy, V. Ray S. Starting from the earliest evidences of archaeologic past based on the recent excavations at Banwali and other sites in Haryana , Hissar , Gujarat etc.
Showing the evidences of archaeological findings related to the textile technology in the Indian context. The chapter would contain illustrations of the excavated findings. The relation of the Indian Textile Technology in the global framework linking it to the earliest evidence of actual fabric discovered in Egypt which has a bearing on the direct trade relation with the Gulf of Cambay. The indigo dyed fabrics of the 9th century A. The period covered here would be till Mugal times.
Textile Reference Book for Technologies Finishing
Here three levels of processes will be discussed in the sections: Pre-woven, Woven, Post-woven. The regional strengths and the inter-regional influences will find a place here. The highlights of the tribal and the folk textile elements will also be discussed here. The chapter would contain pictures and illustrations, line drawings etc.
Discussing the effects of several invasions, rules particularly the Sultanate, Mughal, British rule on the textile manufacture. Rehla of Ibn Batuta, Ain-e-Akbari, Tuzuke Jahangiri, Travel accounts of the British have given very interesting information regarding the systems of textile manufacture, the designers etc. The chapter would discuss case studies of such parallel situations. The resurgence of several technologies, particularly in the field of vegetable colour dyes etc. Khadi as is known today, was the earliest hand spun and hand woven material from India ,which after having got linked with the Gandhian sentiment of Swaraj has now revived itself as the Traditional Indian brand.
This chapter will focus on these aspects. Concluding chapter with the geographic mapping of the traditional textiles centers and their global linkages for trade etc. Therefore it is important to give this consolidated overview. Focus: After the Industrial Revolution, the textile sector was severely affected in terms of the mechanisation of the process of manufacture.
The Book shall thus be dealing with: a. Archeological evidence of textiles from Neolithic times to modern period. All aspects of textile technology including tools, equipment, materials etc. Chapterisation Scheme: Section I The chapters in this section will be based on descriptions of the archaeological, historical materials using mainly library resources.
Chapter 1: This chapter shall deal with characteristics of textile technologies in archaeological perspective. Chapter 2: This chapter will be based mainly on the historical references from the literature, sculptures, paintings, illustrated manuscripts etc.
Section II Based upon the field information this section will cover basic materials, techniques, technologies and skills. Chapter 3 Making of fiber, yarn and the fabric involve several hand technologies. Chapter 4 While dealing with the decorations which are done on yarn before weaving, this chapter will discuss the popular traditions of this technique prevalent in the country highlighting the regional character.
Chapter 5 This chapter will confine discussions to the techniques of decorations employed while weaving in different materials, styles and regions. Chapter 6 Mainly dealing with the surface ornamentation this chapter will be divided in to two parts. Chapter 7 After the independence there has been a concerted effort at various levels in India to revive the fabrics based on the traditional hand technologies. This is hoped to be achieved through: Documenting the tools, equipments, materials required for textile technology of India from pre-historic to contemporary times with proper pictorial details.
Efficacy of various materials adopted for the processing and designing etc. A survey of the sculptures, paintings, ancient Indian literature will be done to demarcate various stages of technology development from the protohistoric times. This will be followed by some limited fieldwork, both to add to the data-base, as well as to understand the processes and techniques of traditional technologies including through interactions with people still using traditional methods or those who have successfully added newness to rejuvenate traditions.
The field work would be carried out in various parts of the country, which are renowned centers of production of the traditional textiles. I also intend holding consultations and interactions with artisans and weavers related to the manufacture of the textiles, archaeologists, related experts, and fashion designers etc.
This will help in systematic comprehension and analysis of the traditional textile technology of India. An attempt will be made to understand the economic status of the grass root communities involved in using traditional textile technologies and the effective propagation of these technologies in the contemporary global market in view of the WTO and textile trade policy. Textiles have been existing since the times man learnt to cover his body. There have been many technological innovations and advancements but the ancient technologies of the textile manufacture have continued to coexist with the new innovative technologies.
Therefore while on one hand there is an archaic past of these technologies , there is also a continuum with the modern technology. This study in total is thus an attempt to understand the development, historical growth, downfall and recent resurgence of the traditional technologies pertaining to the manufacture and decoration of the textiles in India from the protohistoric times to present day.
The study would also briefly touch upon the futuristic vision of the traditional textiles technologies of India, their status in the global textile trade, the apprehensions and the strengths of survival. Time-Frame: It is visualised that the final document, which will take the shape of a published text of about pages, shall take a minimum of 18 months to complete. Bibliography: Bag, A.
Perincek et. For this purpose, a detailed investigation on the role of the fiber moisture, pH, and treatment time during ozonation was carried out. Also, the effect of ozonation on the dyeing properties of Angora rabbit fibers was researched.
Consequently, it was found that ozonation improved the degree of whiteness and dyeability of Angora rabbit fiber [ 57 ]. Atav and Yurdakul investigated the use of ozonation to achieve dyeability of the angora fibers at lower temperatures without causing any decrease in dye uptake by modifying the fiber surfaces. The study was carried out with known concentration of ozone, involving process parameters such as wet pick-up WP , pH, and treatment time.
The effect of fiber ozonation was assessed in terms of color, and test samples were also evaluated using scanning electron microscopy SEM. Dyeing kinetics also studied and it was demonstrated that the rate constant and the standard affinity of ozonated sample increased [ 54 ]. Faraday proposed to classify the matter in four states: solid, liquid, gas and radiant.
Researches on the last form of matter started with the studies of Heinrich Geissler : the new discovered phenomena, different from anything previously observed, persuaded the scientists that they were facing with matter in a different state. Sufficient additional energy, supplied to gases by an electric field, creates plasma [ 62 ]. The plasma is referred to as the fourth state of matter in addition to solid, liquid, gaseous [ 63 ].
The plasma is an ionized gas with equal density of positive and negative charges which exist over an extremely wide range of temperature and pressure [ 65 ]. As shown in Fig. There are different methodologies to induce the ionization of plasma gas for textile treatment [ 65 ]:. Glow Discharge: It is the oldest type of plasma; it is produced at reduced pressure and assures the highest possible uniformity and flexibility of any plasma treatment [ 67 ]. The methodology applies direct electric current, low frequency over a pair of electrodes [ 65 ]. Alternatively, a vacuum glow discharge can be made by using microwave GHz power supply [ 68 ].
Corona Discharge: It is formed at atmospheric pressure by applying a low frequency or pulsed high voltage over an electrode pair [ 65 ]. Typically, both electrodes have a large difference in size. The corona consists of a series of small lightning-type discharges. High local energy levels and problems related to the homogeneity of the classical corona treatment of textiles make it problematic in many cases [ 68 ]. Dielectric-Barrier Discharge: DBD is produced by applying a pulsed voltage over an electrode pair of which at least one is covered by a dielectric material [ 65 ].
Although lightning-type discharges are created, a major advantage over corona discharges is the improved textile treatment uniformity [ 68 ]. Practically, one generates the plasma by applying an electrical field over two electrodes with a gas in between. This can be carried out at atmospheric pressure or in a closed vessel under reduced pressure. In both cases, the properties of the plasma will be determined by the gasses used to generate the plasma, as well as by the applied electrical power and the electrodes material, geometry, size, etc.
The pressure of the gas will have a large influence on the plasma properties but also on the type of equipment needed to generate the plasma [ 69 ]. The plasmas can be classified as being of the low pressure and atmospheric type.
General References - Textiles - Knovel
Both plasmas can be used for the surface cleaning, surface activation, surface etching, cross linking, chain scission, oxidation, grafting, and depositing of materials, and generally similar effects are obtained; however, atmospheric plasma has many advantages when compared with vacuum plasma [ 70 ]. Low pressure plasmas are typically in the pressure range of 0. A vacuum chamber and the necessary vacuum pumps are required, which means that the investment cost for such a piece of equipment can be high. These plasmas are characterized by their good uniformity over a large volume.
Open systems using the surrounding air exist. The range of processes is not as wide as for low pressure plasmas. On the other hand, these systems are easily integrated in existing finishing lines, a major advantage from industrial view point. Of course, for an inline process to be feasible, the plasma treatment has to be done at sufficiently high line speeds, which is not evident for textile materials [ 69 ]. Due to increasing requirements on the finishing of textile fabrics, increasing use of technical textiles with synthetic fibers, as well as the market and society demand for textiles that have been processed by environmentally sound methods, new innovative production techniques are demanded [ 66 ].
Plasma technology is an important alternative to wet treatments, because there is no water usage, treatment is carried out in gas phase, short treatment time is enough, it does not cause industrial waste, and it provides energy saving [ 71 ]. In Cold plasma, that is, low-temperature plasma LTP treatment is the most commonly used physical method for a surface specific fiber modification, as it affects the surface both physically and chemically [ 72 ].
The advantage of such plasma treatments is that the modification turns out to be restricted in the uppermost layers of the substrate, thus not affecting the overall desirable bulk properties [ 62 ]. The plasma gas particles etch on the fabric surface in nano scale so as to modify the functional properties of the fabric. Unlike conventional wet processes, which penetrate deeply into fibers, plasma only reacts with the fabric surface and does not affect the internal structure of the fibers.
Plasma technology modifies the chemical structure as well as the topography of the textile material surface. In conclusion, plasma can modify the surface properties of textile materials, deposit chemical materials plasma polymerization to add functionality, or remove substances plasma etching from the textile materials [ 65 ]. Essentially, four main effects can be obtained depending on the treatment conditions;. The cleaning effect: It means the removal of impurities or substrate material from the exposed surface [ 73 ].
It is mostly combined with changes in the wettability and the surface texture. This leads for example to an increase in dye-uptake. Increase of microroughness: This affects, for example, an anti-pilling finishing of wool. Generation of radicals: Presence of free radicals induces secondary reactions like cross-linking.
Furthermore, graft polymerization can be carried out as well as reaction with oxygen to generate hydrophilic surfaces [ 66 ]. Plasma polymerization: In plasma polymerization, a monomer is introduced directly into the plasma and the polymerization occurs in the plasma itself [ 73 ]. It enables the deposition of solid polymeric materials with desired properties onto the substrates [ 66 ]. When a surface is exposed to plasma a mutual interaction between the gas and the substrate takes place. The surface of the substrate is bombarded with ions, electrons, radicals, neutrals and UV radiation from the plasma while volatile components from the surface contaminate the plasma and become a part of it.
Low temperature plasma treatment of wool has emerged as one of the environmental friendly surface modification method for wool substrate. The efficiency of the low temperature plasma treatment is governed by several operational parameters like;. Plasma treatment can impart anti-felting effect, degreasing, improved dyestuff absorption and increased wetting properties to wool fibers [ 68 ].
These effects of the plasma process are attributed to several changes in the wool surface, such as;. Plasma treatments modify the fatty acid monolayer present in the outermost part of the wool fiber, generating new hydrophilic groups as a result of the hydrocarbon chain oxidation and reducing the fatty acid chain length. The oxidation process also promotes the formation of Bunte salt and cysteic acid residues on the polypeptide chain. Particularly when oxidizing gasses are used, plasma induces cystine oxidation in the A-layer of the exocuticle, converting it into cysteic acid and thus reducing the number of crosslinkages in the fiber surface [ 72 ].
As the surface is oxidized, the hydrophobic character is changed to become increasingly hydrophilic [ 76 ]. The etching of the hydrophobic epicuticle and increase in surface area also contributes towards the improvement in the ability of the fibers to wet more easily [ 74 ]. Plasma treatment of wool fibers causes improvement in dyeability of wool fibers due to the changes occurred on fiber surface. For this reason dyeing kinetics, dye uptake and hence depth of shade are increased.
In literature there are many studies related to the effect of plasma treatment on dyeability of proteinous fibers. Some of them are summarized below. Wakida et al. Dyeing rate and final dye uptake increased with the atmospheric low-temperature plasma treatments. Yoon et al. Plasma pretreatment caused an increase in strength.
Furthermore, it was observed that when wool was dyed with a leveling acid dye, equilibrium dye uptake did not change, but the dyeing rate increased with a milling acid dye [ 78 ]. Jing investigated the surface modification of silk fabric by plasma graft copolymerization with acrylamide and acrylic acid. The dependence of graft degree was examined on the conditions of plasma grafting.
The relationships were discussed between graft degree and factors such as crease recovery, dyeability, colour fastness and mechanical properties. It was shown that the dyeability and color fastness have been improved for samples grafted with acrylic acid [ 79 ]. Despite the increase of electronegativity of the fiber surface caused by the plasma treatment, the rate of dyeing of wool was increased with both dyes [ 80 ]. The dyeing rate of the plasma-treated wool increased considerably with cochineal, Chinese cork tree, and madder, but not with gromwell. Furthermore, plasma-treated wool fabrics dyed with cochineal and Chinese cork tree have increased brightness compared with untreated wool [ 81 ].
Kan et al. After the low-temperature plasma treatment, the treated wool fabric specimens exhibited better hydrophilicity and surface electrostatic properties at room temperature, together with improved dyeing rate. The occurrence of some grooves on the fiber specimens was determined by scanning electron microscope and it was stated that these grooves might possibly provide a pathway for a faster dyeing rate [ 82 ].
The results showed that LTP treatments can alter the dyeing properties to various degrees. The nature of the LTP gases plays an important role in affecting the behavior of chrome dyeing [ 83 ]. After the low temperature plasma LTP treatment, those properties of the LTP-treated substrates changed, and the changes depended on the nature of the plasma gas used [ 84 ]. Investigations showed that chemical composition of wool fiber surface varied differently with the different plasma gas used. Iriyama et al. All plasma-treated silk fabrics showed weight loss, especially by O 2 plasma.
Color fastness to wet rubbing of silk fabrics was not improved by plasma treatment. However, most of them were still within the level for commercial use [ 86 ]. Sun and Stylios , have investigated the effects of LTP on pre-treatment and dyeing processes of cotton and wool. The contact angles, wicking properties, scourability, and dyeability of fabrics were affected by low-temperature plasma treatments. After treatment, the dye uptake rate of plasma treated wool has been shown to increase. It has been shown that O 2 plasma treatment increases the wetability of wool fabric and also the disulphide linkages in the exocuticle oxidize to form sulphonate groups which also enhances the wetability [ 87 ].
Binias et al. The level of changes was limited by parameters of the low-temperature plasma. Lowering of the dyeing temperature was achieved [ 88 ]. Jocic et al. Wool knitted fabrics were treated and characterized by whiteness and shrink-resistance measurements. Surface modification was assessed by contact-angle measurements of human hair fibers. It was stated that after plasma treatment the whiteness degree and hydrophility of fibers increased and fiber dyeability was improved [ 71 ].
Sun and Stylios , have determined the mechanical and surface properties and handle of wool and cotton fabrics treated with LTP. This investigation showed that the mechanical properties of wool changed remarkably after oxygen plasma treatment. Masukuni and Norihiro , studied the dyeing properties of Argon Ar -plasma treated wool using the six classes of dyestuffs, i.
Ar-plasma treatment greatly improved the color yield and levelness, together with the decrease of tippy dyeing. A condition in the plasma treatment enhanced not only the color yield but also the anti-felting performance. The relationship between the improvement of dyeing properties by the plasma treatment and the chemical structure of the dyes was also examined. In the case of the acid dyes, the effect of plasma treatment on color yield was more significant for the milling type dyes with large molecular weight than the leveling type dye with low molecular weight.
Furthermore, the hot water and rubbing fastness were improved by Ar-plasma treatment [ 90 ]. Kan and Yuen treated the wool fibers with oxygen plasma and then dyed these fibers with acid, chrome and reactive dye. For acid dyeing, the dyeing rate of the LTP-treated wool fiber was greatly increased, but the final dye uptake equilibrium did not show any significant change. For the chrome dyeing, the dyeing rate of the LTP-treated wool fiber was also increased, but the final dye uptake equilibrium was only increased to a small extent. For the reactive dyeing, the dyeing rate of the LTP-treated wool fiber was greatly increased, and the final dye uptake equilibrium was also increased significantly [ 91 ].
El-Zawahry et al. The LTP-treatment resulted in a dramatic improvement in fabric hydrophilicity and wettability, the removal of fiber surface material, and creation of new active sites along with improved initial dyeing rate. Prolonging the exposure time up to 20 minutes resulted in a gradual improvement in the extent of uptake [ 92 ].
Demir et al. The treated fabrics were evaluated in terms of their dyeability, color fastness and shrinkage properties, as well as bursting strength. The surface morphology was characterized by SEM images. In order to show the changes in wool surface after plasma treatment, XPS analysis was done. According to the experimental results it was stated that atmospheric plasma has an etching effect and increases the functionality of a wool surface [ 93 ]. Chvalinova and Wiener investigated the effects of atmospheric pressure plasma treatment on dyeability of wool fabric.
Untreated and plasma treated wool materials were dyed with acid dye in weak acid solution pH 6. Experiments showed invasion of surface layer of cuticle by plasma and it was observed that the plasma treated wool fabric for seconds, absorbed double more dye than untreated wool fabric [ 94 ]. Naebe et al. X-ray photoelectron spectroscopy and time-of-flight secondary ion mass spectrometry confirmed removal of the covalently-bound fatty acid layer F-layer from the surface of the wool fibers, resulting in exposure of the underlying, hydrophilic protein material.
The dyes used were typical, sulfonated wool dyes with a range of hydrophobic characteristics, as determined by their partitioning behavior between water and n-butanol. No significant effects of plasma on the rate of dye adsorption were observed with relatively hydrophobic dyes. In contrast, the relatively hydrophilic dyes were adsorbed more rapidly and uniformly by the plasma-treated fabric [ 95 ].
Demir treated the mohair fibers by air and argon plasma for modifying their some properties such as hydrophilicity, grease content, fiber to fiber friction, shrinkage, dyeing, and color fastness. The results showed that the atmospheric plasma has an etching effect and increases the functionality of a fiber surface. The hydrophilicity, dyeability, fiber friction coefficient, and shrinkage properties of mohair fibers were improved by atmospheric plasma treatment [ 96 ].
Atav and Yurdakul investigated the use of plasma treatment for the modification of fiber surfaces to achieve dyeing of mohair fibers at lower temperatures without decreasing dye uptake. The study was carried out by using different gases under various powers and times. The effect was assessed in terms of color. Test samples were also evaluated using scanning electron microscopy SEM. Dyeing kinetics was also searched in the study and it was demonstrated that the rate constant and the standard affinity of plasma treated sample was increased [ 97 ].
Gamma rays are identical in nature to other electromagnetic radiations such as light or microwaves but are of much higher energy. Examples of gamma emitters are cobalt, zinc, cesium, and radium Like all forms of electromagnetic radiation, gamma rays have no mass or charge and interact less intensively with matter than ionizing particles [ 99 ]. Studies on the interaction of high energy radiation with polymers have attracted the attention of many researchers.
The efficiency of these two types of reactions depends mainly on polymer structure and irradiation atmosphere. However, dose rate, types of radiation source and temperature during irradiation can influence the reaction rates [ ]. For some applications radiation degradation can be controlled and devoted to achieve a specific property [ ]. Degradation, in broad terms, usually involves chemical modification of the polymer by its environment; modification that is often but not always detrimental to the performance of the polymeric material. Although the chemical change of a polymer is frequently destructive, for some applications degradation can be controlled and encouraged to achieve a specific property.
In this regard, different vinyl monomers have been grafted onto gamma irradiated wool fabric to improve some favorable properties such as dyeability, and moisture regain. These studies have been based on the formation of stable peroxides on wool, upon irradiation, which are thermally decomposed to initiate polymerization [ ]. Gamma rays are ionizing radiations that interact with the material by colliding with the electrons in the shells of atoms.
They lose their energy slowly in material being able to travel through significant distances before stopping. The free radicals formed are extremely reactive, and they will combine with the material in their vicinity. The irradiated modified fabrics can allow: more dye or pigment to be fixed, producing deeper shades and more rapid fixation of dyes at low temperature [ 32 ].
In literature it is stated that two kinds of effects might occur in parallel in wool during the irradiation. The first effect as manifests as an evident decrease in dye accessibility at lower doses may not be altogether independent of crosslinking. On the other hand, the remarkable increase in the uptake at higher doses seems to be associated with strong structural damage of fibers. It is interesting to note that the increase in accessibility to dyes of the highly irradiated fibers is so great that the bilateral structure is hardly visualized by the partial staining.
Thus the cross-sections of fibers irradiated with a dose of 10 8 roentgens are stained uniformly in dark tone even under the condition which does not give rise to the staining of unirradiated fibers [ ]. In literature there are limited studies related to the effect of gamma irradiation treatment on dyeability of proteinous fibers. Horio et al.
It was found that the dyeing property of wool fiber was greatly affected by irradiation even at low doses where any changes in mechanical properties were not noticeable. The rate of dye absorption was strongly depressed by irradiation with Co gamma radiation of low doses from 10 3 to 10 5 roentgens. Two dyestuffs, C.
Acid Red 44 and C. Acid Green 28 were used. The dye absorption was strikingly suppressed at the range of doses from 10 3 to 10 5 roentgens, but fibers regain dye accessibility at higher doses [ ]. Beevers and McLaren have been found that small doses of gamma radiation 0. The results indicate that even small doses of gamma radiation break sufficient covalent bonds to make the crosslinked peptide chain structure more susceptible to the action of swelling and disordering agents. These small radiation-induced changes can be expected to affect properties of wool significantly in absorption and penetration processes, such as those involved in dyeing, chemical modification, and grafting treatments of wool [ ].
The effects of the two forms of radiation on the natural fluorescence of wool, permanent setting, printing properties and the epicuticle layer were also described [ ].
In the last decade, considerable effort has been made in developing surface treatments such as UV irradiation, plasma, electron beam and ion beam to modify the properties of textile materials. Laser modification on material surface is one of the most studied technologies [ ]. A laser is a device that emits light electromagnetic radiation through a process of optical amplification based on the stimulated emission of photons.
Laser processing as a new processing method, with its processing of accurate, fast, easy, automatization, in leather, textile and garment industry increasingly widely used [ ]. Laser technology has been widely used in surface modification of polymers [ ]. Since the late 90s, different types of commercial lasers are available for surface modification of materials [ ].
While most of the efforts in developing surface treatments have been made using UV laser, infra-red lasers, like CO 2 appear to be less concerning [ ]. Adequate power levels for a specific application are very important in surface modification processes, because an excessive amount of energy can damage the polymers. Infra-red lasers like CO 2 are the most powerful lasers; with no suitable power level, severe thermal damage can be resulted. However, this short coming can be overcome by the use of pulsed-mode CO 2 lasers, which are easier to control than lasers operating in the continuous wave mode [ ].
Excimer lasers, which are a form of ultraviolet lasers [ ], are a special sort of gas laser powered by an electric discharge in which the lasing medium is an excimer, or more precisely an exciplex in existing designs. These are molecules which can only exist with one atom in an excited electronic state. Once the molecule transfers its excitation energy to a photon, therefore, its atoms are no longer bound to each other and the molecule disintegrates. This drastically reduces the population of the lower energy state thus greatly facilitating a population inversion.
Excimers currently used are all noble gas compounds; noble gasses are chemically inert and can only form compounds while in an excited state. Excimer lasers typically operate at ultraviolet wavelengths [ ]. Physical modifications occur in the form of a certain, regular surface structure of the irradiated sites. The high energy input of the excimer radiation into the polymer might also give rise to chemical changes of the surface [ ]. In the case of polymers, some well-oriented structure of grooves or ripple structures with dimensions in the range of micrometer are developed on surface with irradiation fluence above the so-called ablation threshold.
The laser irradiation of highly absorbing polymers can generate characteristic modifications of the surface morphology. The physical and chemical properties are also affected after laser irradiation. Hence, it is reasonable to believe that such surface modification of a polymer may have an important impact on its textile properties [ ]. The possible applications of laser technology in the textile industry include removal of indigo dye of denim, heating threads, creating patterns on textiles to change their dyeability, producing surface roughness, welding, cutting textile webs.
Laser irradiation on polymer surface is used to generate a modified surface morphology. The smooth surface of polymers is modified by this technique to a regular, roll-like structure that can cause adhesion of particles and coating, wetting properties and optical appearance [ ]. Laser technology can also be used for improving dyeability since it is well known that the UV output from excimer lasers can modify the surface of synthetic fibers. But the use of laser energy in textile treatment is still uncommon and is generally limited with denim garment finishing [ ].
Although there are many studies in the literature related to the investigation of the effect of laser treatment on dyeability of many fiber types, there is still no study carried out on wool. But, by taking into consideration that the chemical structure and dyeing property of proteinous fibers is similar to polyamide, in the light of the studies carried out on polyamide [ , ], it can be said that dyeability of proteinous fibers with anionic dyes such as acid and reactive dyes may increase due to the decrease in the crystallinity and increase in free amino groups of the fiber.
Microwaves MW which have broad frequency spectrum are electromagnetic waves that are used in radio, TV and radar technology [ ]. MWs are radio waves with wavelengths ranging from as long as one meter to as short as one millimeter, or equivalently, with frequencies between MHz 0. Microwaves travel in matter in the same manner as light waves: they are reflected by metals, absorbed by some dielectric materials and transmitted without significant losses through other materials.
For example, water, carbon, foods with a high water, some organic solvents are good microwave absorbers whereas ceramics, quartz glass and most thermoplastic materials absorb microwaves slightly [ ]. Electromagnetic waves can be absorbed and be left as energy units called photon. The energy carried by photon is depended on the wavelength and the frequency of radiation. Energy of MW photons is 0. This value is very low considering the necessary energy for chemical bonds.
Therefore MW rays can not affect the molecular structure of the material directly and change the electronic structures of atoms [ ]. Microwave-promoted organic reactions are known as environmentally benign methods that can accelerate a great number of chemical processes. In particular, the reaction time and energy input are supposed to be mostly reduced in the reactions that are run for a long time at high temperatures under conventional conditions [ ]. Reactions conducted through microwaves are cleaner and more environmentally friendly than conventional heating methods [ ].
The use of microwave radiation as a method of heating is over five decades old.
velvetis.lt/wp-content/chula/contactos-mujeres-vilanova-i-la-geltru.php Microwave technology originated in , when Dr. Percy Le Baron Spencer, while conducting laboratory tests for a new vacuum tube called a magnetron, accidentally discovered that a candy bar in his pocket melted on exposure to microwave radiation. Spencer developed the idea further and established that microwaves could be used as a method of heating. Subsequently, he designed the first microwave oven for domestic use in Since then, the development of microwave radiation as a source of heating has been very gradual [ ].
Microwave heating occurs on a molecular level as opposed to relying on convection currents and thermal conductivity when using conventional heating methods. This offers an explanation as to why microwave reactions are so much faster [ ].
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The fundamental mechanism of microwave heating involves agitation of polar molecules or ions that oscillate under the effect of an oscillating electric or magnetic field. In the presence of an oscillating field, particles try to orient themselves or be in phase with the field. However, the motion of these particles is restricted by resisting forces inter-particle interaction and electric resistance , which restrict the motion of particles and generate random motion, producing heat [ ].
Microwave MW heat systems consists of three main units; magnetron, waveguide and applicator. Magnetron is used as a microwave energy source in industrial and domestic type of microwave ovens. One of the oscillator tube, magnetron consists of two main parts as anode - cathode, and it converts the continuous current - electrical energy to MW energy.
Circulator transmits approximately all of the waves that are sent from magnetron and shunts transmitted waves to water burden. Thus magnetron is protected. Electromagnetic waves are transmitting to the applicator by waveguides. Applicators are parts of the matter MW applied on. MW energy produced in generator is affected directly on the material in applicators in MW heating systems. Since the beginning of the twentieth century MW technology has made significant contributions to scientific and technological developments.
Also due to its initial intend to be used in telecommunications, very important progresses have been made in this area. Nevertheless from the second half of twentieth century, MW energy is finding increased number of application area in other industrial processes and these applications are surpassing telecommunication applications [ ]. In textile processing it is necessary to apply heat as in dye fixation, heat setting or drying the product.
Heat can be transferred to the material by radiation, conduction and convection. These three ways of transferring can be used either separately or in combination. The saving of time and energy is of immediate interest to the textile industry. The introduction of new techniques which will allow less energy to be used: is a highly important area of activity to consider. The textile industry has investigated many uses for microwave energy such as heating, drying, dye fixation, printing and curing of resin finished fabrics.
In , Ciba-Geigy obtained one of the earliest patents for using microwave heating in dyeing and printing fibrous material with reactive dyes. Since then many authors have investigated the feasibility of using microwaves for a variety of dyeing and finishing processes [ ]. Although many studies have focused on investigating the feasibility of using microwaves to dye polyester fibers with disperse dyes, researches related to the use of microwave heating in dyeing of proteinous fibers are very limited.
Delaney and Seltzer used microwave heating for fixation of pad-dyeings on wool and they demonstrated the feasibility of applying certain reactive dyes to wool in fixation times of s [ ]. Zhao and He treated the wool fabric with microwave irradiation at different conditions and then studied for its physical and chemical properties using a variety of techniques, such as Fourier transform infrared spectroscopy, X-ray diffraction, and scanning electron. It was found that microwave irradiation of wool fabric significantly improved its dyeability. It was stated that this could be due to the change in wool surface morphological structure under microwave irradiation which implied that the barrier effect in wool dyeing was diminished.
Although the breaking strength of the treated wool fabrics also improved with microwave irradiation, the chemical structure and crystallinity did not show any significant change [ ]. In literature it was stated that dyeing time of mohair could be drastically reduced from the conventional 90 minutes to 35 minutes using the radio frequency technique, only 5 minutes of the 35 minutes representing actual exposure to the radio frequency field. Turpie quoted unpublished data in which radio-frequency dyeing of tops produced better luster and enabled higher maximum spinning speeds than did conventional dyeing of mohair.
Radiation processing has been increasingly applied in industries to improve the quality of products, efficiency, energy saving and to manufacture products with unique properties [ ]. An irradiation can induce chemical reactions at any temperature in the solid, liquid and gas phase without any catalyst; it is a safe method that could protect the environment against pollution; radiation process could reduce curing time and energy saving; it could treat a large and thick three-dimensional fabrics that need not consider of the shape of the samples [ ].
Physical techniques for activating fiber molecules in the absence of solvent for producing functional textiles are becoming increasingly attractive also from an ecological viewpoint. Among them, electron beam processing is particularly interesting as it offers the possibility to treat the materials without solvent, at normal temperature and pressure [ ]. Whilst the energy of the electrons in gas discharge plasmas is typically in the range of electron volt eV , electron-beam E-beam accelerators generate electrons with a much higher energy, generally keV to 12 MeV.
These electrons may be used to modify polymer materials through direct electron-to-electron interactions. These interactions can create active species such as radicals, so there are different possible outcomes from the electron-beam irradiation of polymer materials, on the basis of the chosen operating conditions [ ]. The formation of active sites on the polymer backbone can be carried out by several methods such as plasma treatment, ultraviolet UV light radiation, decomposition of chemical initiator and high-energy radiation [ ].
At present, the most common radiation types in industrial use are gamma and e-beam. E-beam machines play a significant role in the processing of polymeric materials; a number of different machine designs and different energies are available. Industrial e-beam accelerators with energies in the keV range are in use in applications where low penetration is needed, such as curing of surface coatings. Accelerators operating in the 1. E-beam machines have high-dose rate and therefore short processing times.
While they have limited penetration compared with gamma, they conversely have good utilization of energy because it can all be absorbed by the sample irradiated [ ]. New radiation processing applications involving ion-beam treatment of polymers offer exciting prospects for future commercialization, and are under active investigation in many research laboratories. Studies related to the e-beam irradiation of proteinous fibers are limited. Fatarella et al. Plasma treatments with different non-polymerizing gases oxygen, air and nitrogen and e-beam irradiation in air or nitrogen atmosphere were assessed as possible pretreatments to non-proteolytic enzymatic processes such as TGase to improve the accessibility of target groups in the wool proteins to the enzymes.
In contrast, by increasing the energy of the electrons in e-beam treatments no significant superficial modifications were observed. In fact, they promoted the cleavage of high-energy bond, such as S-S linkage, by enhancing depolymerization reaction [ ]. It has been approximately 50 years since researchers first began exposing polymeric materials to ionizing radiation, and reporting the occurrence of cross-linking and other useful effects. Innovation in this field has by no means ended; important new products made possible through radiation technology continue to enter the marketplace, and exciting new innovations in the application of radiation to macromolecular materials are under exploration at research institutions around the world [ ].
Ionizing radiation may modify physical, chemical and biological properties of materials [ ]. Some of the surface characteristics being successfully manipulated by radiation grafting include: chemical resistance, wetability, biocompatibility, dyeability of fabrics, and antistatic properties [ ]. Ion implantation is an innovative production technique with which the surface properties of inert materials can be changed easily.
It shows distinct advantages because it is environmentally friendly. Ion implantation can be used to induce both surface modifications and bulk property enhancements of textile materials, resulting in improvements to textile products ranging from conventional fabrics to advanced composites. Ion implantation was first done by Rutherford in , when he bombarded aluminum foil with helium ions. Ion implantation has been applied to metals, ceramics, plastics, and polymers [ ]. Even though ion implantation is relatively complex in terms of the equipment required, it is a relatively simple process.
Ion implantation consists of basically two steps: form plasma of the desired material, and either extract the positive ions from the plasma and accelerate them toward the target, or find a means of making the surface to be implanted the negative electrode of a high voltage system [ ]. There are three methods commonly used for ion implantation. They differ in the way in which they either form the plasma or make the surface to be implanted the negative electrode. These methods are mass-analyzed ion implantation, direct ion implantation and plasma source ion implantation [ ].
In mass-analyzed ion implantation , the plasma that is formed in the ion source is not pure; it contains materials that one does not wish to implant. Thus, these contaminants must be separated from the plasma. To perform this separation, the plasma source is placed at a high voltage and the part to be implanted is placed at ground.
This produces a situation where the target is at a negative potential with respect to the plasma source.
Related Reference Books of Textile Technologies: Finishing
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