Application of Low-Pressure Plasma Pretreatment in Silk Fabric Degumming Process

A novel and effective method was developed for raw silk fabric degumming with the application of low-pressure argon plasma in pretreatment combining a subsequent one-step mild wet-chemical process. The plasma parameters, such as argon pressure, discharge power and exposure time, were optimized according to degumming loss and the properties of fabric such as capillary rise, tensile strength, bending rigidity, etc. An optimized plasma pretreatment for raw silk fabric degumming was at 80 Pa of argon gas and 60 W glow discharge power for 5–10 min. The raw silk fabric and fibers pretreated by argon plasma were characterized by scanning electronic microscopy and X-ray powder diffraction. In comparison with a conventional degumming process, the proposed method achieved comparable degumming efficiency and properties of silk fabric, and it was more environmentally friendly by shortening the conventional wet-chemical treatment process, saving the dosage of degumming agents, water and energy.     

Ultrasound-assisted ozone bleaching of cotton

In this study, the effects of ultrasound on ozone treatment processes for bleaching cotton fabrics were investigated and compared with the conventional hydrogen peroxide bleaching process (60 °C over 90 min). Two ultrasonic + ozone treatments of cotton fabric samples were carried out: (1) ozone in an ultrasonic homogenizer (UH) and (2) ozone in an ultrasonic bath. Ozone dosages, temperature and time variations were determined with both ozone-ultrasonic bleaching processes. Whiteness, yellowness, weight, tensile strength properties, FTIR (ATR) spectra and visual appearance, via scanning electron microscopy of treated cotton fabrics as well as chemical oxygen demand (COD) of bleaching effluents, were investigated. It was concluded that the ozone + UH process, conducted for 30 min at 30 °C, produced closely equivalent values of cotton fabric whiteness and yellowness to the classic peroxide bleaching process, with slightly less weight loss, dramatically less COD in the process effluent (29 mg/l for ozone-UH vs. 4,316 mg/l for classical peroxide treatment), and without causing any adverse and/or detrimental effects on loss of fabric strength or elongation of the cotton fabrics. The ozone-UH process also leads to time and energy savings with much less environmental impact. Consequently, the combination of ozonation plus UH carried out at 30 °C over 30 min can be used successfully for cotton bleaching instead of the classic hydrogen peroxide bleaching process.     

Sustainable process for the pretreatment and dyeing of Eri silk

The green process route for pre-treatment and dyeing of Eri silk is proposed and investigated in this study. The natural plant-based saponins were extracted from Sapindus mukorossi by aaqueous extraction technique. Extracted Saponins showed a high emulsification index (68), low surface tension (41 dyne/cm), mild foaming (200 mm), and a slightly acidic pH, these characteristic properties are considered to be best suited for the processing of silk. The degumming was performed using Sapindus extract liquid with a concentration of 10% (owf) for 60 min at a temperature of 95 °C. The Eri silk degumming produced similar weight loss (4.63%), water absorbency (3 s) and optical properties - whiteness (80.33), yellowness (2.27) and brightness (70.05), as compared to the conventional process. The tensile strength (8.28 kgf)) and elongation (34.29%) was found to be better than the properties of the fabric processed with conventional chemical processing. The dyeing of degummed and bleached Eri silk with natural dyes showed comparable colour depth and uniformity of shade as compared to the conventional chemical processing. The overall fastness performance of dyed Eri silk was in line with the industry standards. Advanced characterization techniques such as FTIR was used for structural analysis of treated Eri silk.     

蚕丝中蛋白构象含量与其力学性质间的关系

丝蛋白 (Ｆｉｂｒｏｉｎ)是一种具有优异力学性能的天然有机高分子材料 ,蚕丝是最具代表性的一种 .它既有较高的强度 ,又有较强的韧性 ,其强度甚至超过钢丝 .但蚕丝具有如此优异力学性能的机理还不很清楚[1～ 3 ] .通常认为在丝蛋白中有 3种二级结构 (构象 ) ,即α 螺旋 (α ｈｅｌｉｘ) ,β 片层 ( β ｓｈｅｅｔ)和无规线团 (Ｒａｎｄｏｍｃｏｉｌ) [4,5] .α 螺旋是由链内氢键引起的蛋白结构 ,而 β 片层是由链间氢键引起的蛋白结构 .但有研究表明[3 ,6] ,丝蛋白中还存在另一种由 4个氨基酸残基组成的发夹式结构 :β 转角 ( β ｔｕｒｎ)…     

Compound Finishing of Bombyx mori Silk: A Study of Cold Oxygen Plasma/Titania Sols Treatments and Their Influences on Fiber Structure and Performance

Degummed Bombyx mori (B. mori) silk fabrics modified by cold oxygen plasma (COP) and/or titania sols (TSs) were investigated by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction, field emission scan electronic microscopy (FE-SEM), thermo-gravimetric and differential thermal analysis, and ultraviolet (UV) transmittance methods in this study. FT-IR analysis demonstrated that titania particles were associated with B. mori silk fibers by forming organic?Cinorganic hybrid blends. Processing sequences of COP and TSs, and curing conditions showed significant impacts on the crystalline, thermal, micro-morphological, and UV resistant characteristics of silk fabrics. Crystallinity index by both area and height methods, and crystallite sizes of silk fabrics were calculated as well. Results showed that crystallinity index of finished samples approximate to that of degummed silk fabric could be obtained by applying TSs and curing at 160?°C for 2?min prior to COP treatment, or vice versa with lower temperature of 140?°C for 3?min, whereas the crystallite sizes of treated samples increased slightly. The initial decomposition temperatures of finished samples were elevated by 23?C35?°C with increased char residues at 600?°C, while the transmittance of UVA and UVB of finished samples decreased by 11.7, 17.7%, respectively. FE-SEM analysis revealed that titania particles were associated on the fiber surfaces with different smoothness.     

Effects of Atmospheric Plasma Pretreatments on Pectinase Efficiency in Bioscouring of Linen Fabrics

Pectinase enzyme treatment subsequent to atmospheric air- or argon-plasma surface modification was applied in linen fabric preparation. Wettability by water drop test, wickability by thin layer wicking experiment, residual pectin content and colour of the fabrics were characterized. Results clearly proved that the efficiency of pectinase in improving linen water absorbency can be significantly enhanced by plasma pretreatment. Argon-plasma pretreatment followed by a Beisol PRO enzyme treatment reduced the wetting time considerably and resulted in a fabric surface that has been characterized by the lowest water contact angle (86.6??). All the applied treatments increased the energy of the fibre surface. The alkaline scoured, the argon-plasma treated and the argon-plasma-pectinase treated samples have been characterized by the highest $ \gamma_{S}^{total} $ values. Plasma treatment significantly decreased the whiteness and increased the yellowness of the raw fabrics. However, the enzyme treatment applied after the plasma treatment has overcome the colour differences.     

Ultrasound assisted biobleaching of cotton

In this study, the effect of ultrasound on the activity of the glucose oxidase (GOx) enzyme for bleaching of the cotton fabrics was investigated. Hydrogen peroxide generation with the GOx enzyme from glucose was carried out under ultrasonic homogenizer (UH) and ultrasonic bath support. The aim of using ultrasonic support was to increase the yield of the enzyme reactions. The enzymatically generated hydrogen peroxide was used for bleaching of cotton fabrics. The bleaching process was performed at 90 °C and pH 11 (with NaOH) for 60 min, followed by rinsing at 70 and 50 °C then cold washing. The whiteness degrees of the cotton samples that were bleached by the generated peroxide were compared to the whiteness degrees of the conventionally bleached cotton fabrics. Sufficient whiteness degrees in cotton fabrics could be obtained by enzymatically generated hydrogen peroxide by UH support. The initial whiteness degree of the cotton fabric was 59.9 Stensby degrees; the whiteness was increased to 75.6 Stensby degrees by the GOx enzyme under UH support where the conventional bleaching process yielded a whiteness value of 76.7 Stensby degrees. For efficient cotton bleaching by the GOx enzyme, UH support contributed to the concentration of enzymatically generated hydrogen peroxide by the GOx enzyme. Bleaching of cotton by the GOx enzyme was approved as a more environmentally friendly process compared to the conventional bleaching method in respect of the results of chemical oxygen demand tests.     

Application of selected natural sources on mulberry silk fabric

Silk finds an important place for its elegance, softness, luster, sheen, strength, uniformity suitable for the production of respective valuable textile garments and apparels. Due to the amphoteric character of silk protein polymer, the overall behavior of silk will be enriched when it is applied with natural resources. Based on these considerations, it is proposed in this research work to treat mulberry silk fabric with recovered sericin protein in addition with natural finishing sources like aloevera, amla and nochi in varied combinations followed by coloration with some selected natural sources. After these applications, the silk fabric was undergone for some testing for the determination of color value, fastness behavior, tensile strength, absorbency character, anti-odor and retention aspects, and FTIR graphs. The outcome of the results are convinced to the expectations suitable for the applications in the textile industries for garment and apparel utilities.     

Study on novel eco-friendly anti-creasing agents for natural silk fabric

Three novel eco-friendly anti-creasing agents have been designed and synthesized.The natural silk fabrics treated with them exhibit higher wrinkle recovery degree,strength retention rate and whiteness than those finished with 1,2,3,4-butane tetracarboxylic acid(BTCA).The washing durability of the fabrics treated with the synthesized compounds and BTCA is similar.The chlorine atom.the carboxyl and the s-triazine ring in the synthesized structures and the surface roughness of the silk fabric are all contributive to the improvement of the crease resistance of silk.     

Sodium citrate as an eco-friendly complexing agent for the bioscouring treatment of the cellulosic/lignocellulosic fabrics

A 50% of cotton–50% of flax fabric was subjected to an enzymatic treatment (bioscouring) in ultrasound for removing the compounds which could negatively affect the further specific technological processes as whitening and dyeing. During the scouring process, some parameters of the fabrics are improved. Even EDTA is usually used as a chelating agent in the pretreatments of the fabrics, recent studies aimed to identify new biodegradable complexing agents. In this study, we present the results obtained for bioscouring treatment of the cellulosic/lignocellulosic fabrics in the presence of sodium citrate as a complexing agent. The treatments were made in 0.1 M phosphate buffer of pH 8 and ultrasound media. The samples were immersed in an aliquot containing the commercial pectinolytic product BEISOL PRO, Denimcol Wash-RGN as a surfactant and sodium citrate or EDTA (ethylenediaminetetraacetic acid). The reactions were conducted by varying the enzyme concentration and action time using a central, rotatable second-order compound program. All the parameters determined after bioscouring [weight loss, hydrophilicity, whiteness index, yellowness index, tensile strength, elongation at break, the relative absorbance (A₁₇₃₁) from FT-IR spectra, color strength (K/S) and color difference (ΔE*ab)] of the investigated samples showed in the case of sodium citrate (an eco-friendly biodegradable compound) treatments better or comparable values to treatments conducted using EDTA (non-biodegradable compound).     

Formamidine sulfinic acid used as a bleaching chemical on softwood TMP

In this work, we showed that formamidine sulfinic acid, FAS, can be efficiently used as a bleaching chemical for softwood TMP. The bleaching reaction was very rapid. The brightness achieved is dependent on the temperature and the chemical charge applied. The highest brightness was obtained at pH 10, and the lowest yellowness at pH 12. FAS treated pulps are much more stable toward light-induced yellowing. In all cases, FAS bleaching at pH 12 results in much slower and less intense aging than all other pulps, either untreated or bleached with FAS at pH 8 or 10.     

Ultrasonic assisted improved extraction and dyeing of mordanted silk fabric using neem bark as source of natural colourant

Natural products with therapeutic nature are nowadays warmly welcomed in textiles. Current study is concerned with isolation of tannin from neem bark (Azadirachta indica) and its application onto silk fabric. For improvement in shades, chemical & bio-mordants have been employed at optimal dyeing conditions. It is found that methanolic extract of pH 5 obtained 8 g dye powder after US Treatment for 30 min has given high color strength if used to dye irradiated silk for 65 min at 75 °C. Bio-mordanting using herbal plants has improved the color characteristics as compared to chemical mordants used. ISO standards for color fastness reveal that herbal based bio-mordants have improved the rating from good to excellent as compared to chemical mordants used. It is concluded that US treatment has not only isolate the colorant for neem bark under mild condition but also given excellent characteristic using bio mordants onto silk fabrics.     

Effect of ultraviolet light and heat on the properties of cotton cellulose

The changes in properties of cellulose brought about by ultraviolet (UV) irradiation, heat exposure and by a combination of both treatments were determined. The methods of characterizing the changes included breaking strength, color, yellowness index, thermal analysis, dye adsorption as a measure of changes in fine structure of the fibers, and Turnbull's Blue test as an empirical measure of carboxyl content. The exposures increased the color and yellowness of the samples as well as the carboxyl content and decreased dye adsorption and breaking strength. A shift of the decomposition endotherm of cellulose to lower temperatures was also noted. It appears that, under the exposure conditions used in this study, the changes in carboxyl content, color changes, yellowness index and breaking strength induced by heat are accelerated by an initial exposure to UV light but still simulate heat ageing alone. There also appears to be a correlation between breaking strength and dye uptake.     

Reducing Photoyellowing of Wool Using Nano TiO2

Wool is the most important animal fiber used in textile industries, but its photostability is very low. Scientists have searched for new ways to increase the photostability of wool. As TiO₂ nano particles have features suitable for new applications, the UV-blocking power of nano TiO₂ may be used for protecting fabrics against UV rays. Treatment of wool with TiO₂ can be effective for controlling photodegradation. This study focused on protecting wool fabric against UV rays using nano TiO₂. To this end, oxidized and raw wool were treated with citric acid as the cross-linking agent and different concentrations of nano TiO₂. The whiteness and yellowness of wool fabric samples were reported. XRD patterns proved the existence of TiO₂ nano-particles on the wool surface. Finally, the results revealed that nano TiO₂ is a suitable UV absorber on wool fabric and its effect depends on concentration.     

Organic–inorganic hybrid silica film coated for improving resistance to capsicum oil on natural substances through sol–gel route

This study concerns the organic–inorganic hybrid coating of silica sol based on dyed cotton, silk and wool fabrics in order to increase the repellence to capsicum oil via adding methyltriethoxysilane, octyltriethoxysilane, hexadec-ltrimethoxysilane or tridecafluorooctyltriethoxysilane (FAS) in the inorganic silica sol. The dyed cotton fabric treated with hybrid silica sol doped with FAS (F-silica sol, FAS 4 %) presents oil-repellent capability, and the contact angles of capsicum oil on the treated cotton, silk and wool fabrics are 98.5°, 111.59° and 122.15°, respectively. A high FAS concentration (20 %) can improve the oil-repellent ability to 5 grades comparing to the untreated fabrics. The color strengths (K/S) of the coated fabrics change slightly, while the maximum absorption wavelengths of the coated fabrics are the same as the untreated fabrics. Although the drape coefficient of cotton fabric is increased to 54 % from 39 % after coated with F-silica sol, the effect is not significant. Compared to the weight gain rate of untreated cotton, silk and wool samples (1.89, 1.23 and 2.38 %), the weight gain rate of the cotton, silk and wool samples coated with F-silica sol are 6.99, 4.76 and 7.69 %, respectively. The calculated sol–gel weight gains (5.10, 3.53 and 5.31 %) of coated fabrics indicate that the silica coating is subsistent on the fiber surfaces.     

Alkaline hydrogen peroxide bleaching of cellulose

A closed system bleaching apparatus was designed to determine the kinetics and effects of various factors on alkaline hydrogen peroxide bleaching of textile cellulose fabrics. It was confirmed that perhydroxyl anion is the primary bleaching moiety in alkaline hydrogen peroxide systems. The use of the apparatus in the measurement of fabric color, waste oxygen, and the subsequent calculation of hydroxyl ion, and molecular hydrogen peroxide confirmed that pH and titration of 'free' hydrogen peroxide in alkaline bleaching systems are not good indicators of bleaching mechanism. The role of the cellulose itself in the chemical bleaching system was determined. The rate of bleaching on cotton fabric was shown to be a first order reaction in concentration of perhydroxyl anion at 60 and 90°C. An activation energy of 17kcal/mole was estimated. Decomposition of H₂O₂ into waste oxygen was found to be second order kinetics.     

In Situ Synthesis and Characterization of Nano ZnO on Wool: Influence of Nano Photo Reactor on Wool Properties

This study has been carried out to synthesize nano ZnO on wool fabric and also to investigate influences of nano photo reactors on wool fabric characteristics. Zinc acetate has been used as a precursor and the synthesis process has been done in water and water/ethanol media. The treated wool fabrics were heated at 80°C for 10 h to dehydrate Zn(OH)₂ obtaining ZnO. The fabric samples were then subjected to daylight for 7 days to examine the influence of nano ZnO photo reactor on the fabric properties. SEM images revealed the embedding of ZnO nanoparticles on the fabrics and X‐ray diffraction verified the nanoparticles composition. The Yellowness Index (YI) of the fabrics was measured with Color Eye XTH that has been reduced with increasing pH, Zn(CH₃COO)₂ concentration, ethanol and heating. The lower water contact angle and time of water absorption confirmed higher hydrophilic properties of the treated fabrics. Interestingly, a higher tensile strength obtained on the wool fabrics proved the interaction of ZnO with protein chains of wool, which was verified through lower alkali solubility of treated fabric with nano ZnO and confirmed more benefits of the in situ synthesis process.     

Comparative thermal analysis of Eri,Mori, Muga,and Tussar silk cocoons and fibroin fibers

Wild silks are often extremely durable and have many advantages over the domesticated silk. In this study, three kinds of wild silks—Indian Antheraea mylitta (Tussar), Antheraea assama (Muga), and Philosamia ricini (Eri) silkworm cocoons were successfully degummed and their thermal properties were studied comparatively with domesticated Chinese mulberry (Bombyx mori) silkworm cocoons and fibers. Advanced thermal analysis methods, such as differential scanning calorimetry (DSC) and temperature-modulated DSC were utilized to identify glass transition temperatures (T _g), heat capacity increments at T _g, and degradation temperatures of these silk materials. In addition, the bound water contents and the thermal degradation mechanisms of different silk systems were also quantified using thermogravimetric analysis. Compared with the mulberry silk materials, wild silk materials showed higher thermal stabilities, and variable degradation profiles. These comparative methods would offer a new pathway to understand the physical properties of silk-based biomaterials, such as their tunable thermal, mechanical, optical, and electrical properties. And it could provide useful insights for the development of new silk-based medical devices and sutures with controllable biological functions in the future.     

Dyeing of multiple types of fabrics with a single reactive azo disperse dye

Three novel reactive azo disperse dyes were prepared using 7-acetamide-4-hydroxy-2-naphthalene sodium sulphate as the precursor. The structure of the dyes has the combined characteristics of reactive, disperse, and cationic dyes. Under alkaline conditions (pH 9), the dyes can be applied to cotton, silk, wool, and nylon. Under neutral conditions, they can be used to dye polyester. Under acidic conditions (pH 4.5), they can colour acrylic fabric after conversion of the tertiary amine group to the quaternary ammonium cation. The colour-fastness of the dyed fabrics were also evaluated.     

Activated peroxide bleaching of regenerated bamboo fiber using a butyrolactam-based cationic bleach activator

Regenerated bamboo fibers are potentially a valuable source of renewable fibers for use in a wide variety of applications. As with almost all natural fibers, inherent yellowness must be reduced or eliminated in order for the fibers to be used effectively in processes such as dyeing. Oxidative bleaching in the form of hot alkaline hydrogen peroxide is the most common method for bleaching cellulosic fibers. However, significant fiber damage results, especially in the case of regenerated bamboo. Recently, more benign oxidative bleaching methods have been developed using so-called bleach activators. Reported is an effective bleaching method using a novel bleach activator, N-[4-(triethylammoniomethyl)benzoyl]butyrolactam chloride (TBBC). The ratio of TBBC to hydrogen peroxide and pH were found to be critical to achieving effective bleaching at low temperature. Using equimolar amounts of TBBC and hydrogen peroxide at pH 7 and 50 °C, comparable whiteness and less fiber damage compared with conventional peroxide bleaching was obtained. However, at pH 11.5, TBBC had no effect on whiteness.