The Effects of Ozone Treatment on Soybean Fibers

A set of knitted fabrics comprising soybean fibers was ozonated at room temperature for periods ranging from 2.5 to 300 minutes to identify any accompanying effects on either physical properties (specifically whiteness and burst-strength), fiber surface integrity or microstructure. A hydrogen peroxide treatment was applied to some of the fabric in order to provide a comparison. Ozonation was found to produce a promising increase in whiteness which, after the maximum exposure time, was significantly higher than was achieved using hydrogen peroxide.     

An evaluation of the effectiveness of applying a gelatin–copper complex in the low-temperature bleaching of cotton with hydrogen peroxide

A gelatin–copper complex was prepared and then added as catalyst to a hydrogen peroxide bleaching bath. Cotton fabric was bleached with the new system at low temperature (70 °C). The effects of the gelatin–copper complex on the whiteness, capillary effect, damage, and bleaching rate of the bleached fabric and on the decomposition ratio of hydrogen peroxide were evaluated. These effects were compared with the effectiveness of traditional high-temperature bleaching and low-temperature bleaching without the gelatin–copper complex. The results showed that the gelatin–copper complex enhances the bleaching effectiveness of hydrogen peroxide. The whiteness of cotton fabric bleached with the catalytic complex is comparable with the whiteness achieved with a conventional peroxide system. The catalytic bleaching technology not only realises low-temperature and low-alkali bleaching of cotton with hydrogen peroxide but also reduces fabric strength loss, which meets the requirements of industry for continued development of the wet processing of textiles.     

Bleaching of cotton fabric with peracetic acid in the presence of different activators

Peracetic acid is an efficient oxidant and a good alternative to conventional chemicals for bleaching cotton. In order to establish optimal conditions for its use, giving a high degree of whiteness and good water absorption without damage to the fabric, the chemistry of its consumption and the efficiency of the bleaching process have been examined. The effect of temperature and initial pH was assessed, and in particular the influence of the alkali used to control the pH. The highest and most rapid consumption of peracetic acid was seen with magnesium carbonate, the slowest with sodium hydroxide. The bleaching effect was greatest with sodium carbonate and least with sodium hydroxide, although the differences were not large. In all cases damage to the fabric was minimal. The best conditions for bleaching with peracetic acid were found to be 60 °C and an initial pH 7, in the presence of either sodium carbonate or magnesium carbonate.     

A Pilot-Scale Application of Ozone to Bleach Raw Cotton Fabric Using Various Additives

The influence of various additives on the efficiency of optimized ozone bleaching process at pilot scale has been discussed in this study. The results reveal that the best whiteness (63.79) and strength of bleached fabric is achieved with the addition of surfactant (2 g/L) at an ozone dose of 50 g/h, pH 5, and ozone treatment time of 45 min at room temperature. The dyeing quality of ozone-bleached and hydrogen peroxide-bleached fabric samples is almost identical. The analysis of variance of the experimental data validates that the process parameters have significantly affected the efficiency of ozone bleaching process.     

Surface and bulk analysis of bleaching soybean fabric in the presence of protein hydrolysate

The effect of oxidative and oxidative‐reductive bleaching on the colorimetric, topographical, and mechanical properties of soybean fabric has been investigated by yellowness index, abrasion resistance, tensile strength, Kawabata evaluation system for fabrics, scanning electron microscopy, X‐ray photoelectron spectroscopy, and time of flight secondary ion mass spectrometry in order to examine both the bulk and surface properties. Surface changes to the soybean fiber due to bleaching treatments have been evaluated and the protective effect of protein hydrolysates assessed. Improved tensile strength, flat abrasion performance, and handle maintenance of the soybean fabric was demonstrated with the incorporation of Byco C in both bleaching treatments. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Evaluation of Stabilisers for Peroxide Bleaching

A composite experimental design has been used to investigate the effect of stabiliser concentration, alkali concentration and treatment time on the reflectance (whiteness) and fluidity of hydrogen peroxide bleached cotton fabric. Four stabilisers were investigated under short and long dwell steaming conditions. The results show that this experimental method is well suited to the comparison of stabilisers for peroxide bleaching. The work shows that the conditions required to provide optimum whiteness with low chemical damage vary considerably from stabiliser to stabiliser and from system to system.     

An Investigation in the Use of Ozone Gas in the Bleaching of Cotton Fabrics

Ozone, composed of three atoms of oxygen, can be used to oxidize many inorganic and organic impurities. Because of its high oxidizing capacity, the opportunities and parameters of ozone gas use in bleaching of cotton fabrics were researched in this study. It was found that in a very short time cotton fabrics can be bleached if the water content of cotton-woven fabric was 60% and the pH of the water impregnated was 7. Moreover, ozonation at room temperature was shown to be more efficient than ozonation at high to medium temperatures.     

Low‐temperature bleaching of cotton fabric with a binuclear manganese complex of 1,4,7‐trimethyl‐1,4,7‐triazacyclononane as catalyst for hydrogen peroxide

Bleaching of cellulose fabric with hydrogen peroxide is traditionally conducted under alkaline conditions at high temperature, which leads to greater energy consumption and fibre damage. In this study, a binuclear manganese complex of the ligand 1,4,7‐trimethyl‐1,4,7‐triazacyclononane as the catalyst for hydrogen peroxide bleaching was synthesised via a simplified method. Low‐temperature bleaching of cotton fabric with the manganese complex and the effect of key bleaching variables on the bleaching performance were investigated. Hydrogen peroxide could be catalysed to bleach cotton knitted fabric at a temperature as low as 60 °C by incorporating the complex in the bleaching solution. The whiteness index of the fabric bleached at low temperature was lower than that of fabric bleached at high temperature, but the bursting strength retention is much better for the fabric bleached at low temperature. The low temperature is energy‐saving and has environment‐friendly advantages over the traditional high‐temperature method.     

Synthesis of novel bleaching catalyst containing macrocyclic manganese complexes and potential applications in laundry detergent

A bleaching catalyst based on manganese complexes, consisting of meso-5,5,7,12,12,14-hexamethyl-1,4,8,11-tetraazacyclotetradecane and racemic-5,5,7,12,12,14-hexamethyl-1,4,8,11-tetraazacyclotetradecane ligands, was synthesized and applied at 25°C to cotton fabrics stained with tea, coffee, curry, and sugar beet to examine the bleaching properties. The bleaching performance of this novel catalyst was higher than that of the conventional activator, tetraacetyl ethylenediamine (TAED). Dye and fabric damage were also examined for six differently dyed test fabrics under stressed conditions over 30 wash cycles. The dye damage induced by the catalyst was significantly less than that induced by TAED in direct black 22, reactive blue 225, reactive red 158, and sulfur blue 19. Tensile strength loss measurement, which represents fabric damage, showed less damage for the catalyst in direct black 22, direct blue 71, reactive red 158, and sulfur blue 19. The results indicate that this new bleaching catalyst could potentially be employed for low-temperature bleaching.     

Performance of a new cationic bleach activator on a hydrogen peroxide bleaching system

The performance of a cationic bleach activator, N -[4-(triethylammoniomethyl)benzoyl]caprolactam chloride, was evaluated in a hot peroxide bleaching process. The effect of time, temperature and the concentrations of hydrogen peroxide and activator on the bleaching of cotton fabric was investigated using a central composite experimental design. Temperature was found to be the most significant parameter. By adding the cationic activator it was possible to achieve a level of whiteness comparable to a typical commercial bleaching system but under relatively mild conditions of time and temperature. As a consequence, chemical damage to the fabric could be reduced. The effect of the cationic bleach activator was compared to that of an anionic activator, nonanoyloxybenzene sulphonate. The cationic activator was superior to the anionic activator in bleaching the fabric under the optimised conditions used in the study. Received: 13 January 2004, Accepted: 10 March 2004     

Kinetics of staining and bleaching

Kinetics of staining and stain removal have been studied with food dyes and natural colorants. Kinetics of staining indicate that the staining agent is adsorbed on the fiber surface and diffuses into the interior of the fibers. Similarities exist between staining and dyeing mechanisms of cotton, polyester and nylon fibers. Stain removal by nonoxidative detergency involves diffusion of the staining agent from the interior of fibers and desorption from the fiber surface. The kinetics of stain removal by bleaching with peroxyacids or activated sodium perborate depend on the affinity of the stain to fibers. When desorption of stain is rapid, bleaching of the stain in solution is the rate- determining step and stain removal obeys pseudo- first- order kinetics. When the stain is washfast, the concentration of the stain in fibers decreases with the square root of time, indicating a diffusion process. The peroxygen bleaching agent is sorbed in the subsurface of fibers or diffuses into the interior of fibers. If bleaching occurs in the outer perimeter of fibers, the rate- determining step may be the diffusion of stain molecules from the interior of fibers to the location of the bleaching agent. On the other hand, if bleaching occurs within fibers, the rate- determining step may be diffusion of the bleaching agent to the stain located within the fibers. *To whom correspondence should be addressed.     

Economic Viability of Pilot-Scale Application of Ozone in Cotton Bleaching with Multiple Reuse of Water

In this research, potential of reusing bleach water bath was examined with respect to its effect on whiteness of the cotton fabric exposed to 50 g/h of ozone on pilot scale for 45 min with 3 kg of fabric charged fresh at each trial, along with the evaluation of the economic viability of this technology in terms of profit per batch as well as profit per unit product (fabric) computed by Cost of Goods Sold statement. Results have shown that water can be reused with insignificant change in whiteness, revolving around 54% and 60%, and that it harnesses a 7 Rupees profit per unit fabric or 21 Rupees profit per cycle, which seems quite acceptable at existing bleached fabric sale price.     

Bioscouring of cellulosic textiles

A study on bioscouring of cotton yarn with the pectinase enzyme was carried out and the results compared with the usual alkali scoured material. The results indicate that the bioscoured yarn has lower percentage of non‐cellulosic constituents (impurities), higher tenacity, higher absorbency and the same whiteness after hydrogen peroxide bleaching as compared with the Solomatic bleached yarn. A similar study on cotton fabric indicates that a combined desizing and bioscouring is not feasible at least at ambient temperature. More work, however, is required to compare bioscouring followed by bleaching with the Solomatic or two step scouring and bleaching methods. One interesting finding is that the efficiency of washing of the desized fabric improves on adding ethylene diamine tetraacetic acid sequestrating agent in the wash liquor. Additional advantages of bioscouring are lower energy cost and more easily biodegradable effluent in comparison to alkali scouring.     

Photo bleaching of wool using nano TiO2 under daylight irradiation

Wool bleaching is usually carried out on raw wool through treatment with oxidizing or reducing agents. Here, nano TiO₂ as a photocatalyst was applied on raw wool fabric to decompose the naturally occurred pigments under daylight irradiation. To enhance nano particles adsorption on the fabric, it was first treated with protease and then treated with nano TiO₂ along with citric acid. The whiteness and yellowness indexes and hydrophilicity features of the treated wool fabrics indicated a reasonable whiteness with a significant improved hydrophilicity. This new wool bleaching approach was named as “nano photo bleaching” as a most successful bleaching application.     

Adsorption Isotherms for Bleaching Soybean Oil with Activated Attapulgite

Activated attapulgite was characterized and used as bleaching clay (adsorbent) for soybean oil. Adsorption isotherms for bleaching soybean oil were determined to investigate the applicability of the Langmuir and Freundlich equations and to elucidate the adsorption characteristics of oil on activated attapulgite. The Freundlich model was found to provide a better fit with the experimental data than the Langmuir model. The larger Freundlich constant, K _F at higher temperature indicated more effective adsorption. The heat evolved for oil bleaching increased as the levels of activated attapulgite increased from 0.5 to 3%, due to the increase in adsorptive sites with increasing attapulgite levels as well as multilayer adsorption driven by van der Waals’ forces at smaller amounts of adsorbents. There are enough adsorptive sites with 3% attapulgite to adsorb the pigments associated with soybean oil bleaching. The amount of attapulgite has no effect on ΔH _a when it is >3%, and ΔH _a is about 32 kJ/mol.     

聚乙二醇/醚化二羟甲基二羟基乙烯脲树脂整理涤纶织物的研究

对普通涤纶织物进行不同实验条件下的差别化亲水整理、测试、分析和比较,得出用聚乙二醇/醚化二羟甲基二羟基乙烯脲树脂混合整理液进行亲水整理后,织物的亲水性提高较大,且具有较好的耐洗性,其白度几乎不变,透气性与断裂强力稍有下降,织物手感稍微变硬。     

An amperometric titration method for bleach evaluation

An analytical method has been devised as a rapid screening procedure which predicts how effective an active chlorine containing compound will be as a bleaching agent. The method is based on an amperometric titration which indicates bleaching performance from both the increase in whiteness and fabric tendering standpoints. Excellent correlation was obtained between amperometrically determined data and practical bleaching data for several extensively used bleaching agents. In connection with this amperometric titration method, a polarographic method is also presented which provides good correlation between the polarographically determined data and practical bleaching data.     

Laccases to Improve the Whiteness in a Conventional Bleaching of Cotton

This study reports for the first time on the enhancement of the bleaching effect achieved on cotton using laccase enzyme. Laccases applied in short‐time batchwise or pad‐dry processes prior to conventional peroxide bleaching, improved the end fabric whiteness. The whiteness level reached in the combined enzymatic/peroxide process was comparable to the whiteness in two consecutive peroxide bleaches.

Effect of 10 min laccase pre‐treatment at 60 °C, pH 5 on fabrics whiteness before and after a conventional hydrogen peroxide bleaching.     

Synthesis,Characterization, and Toxicological Properties of New Cationic Bleach Activators

Three new bleach activators for cotton containing pyridinium (PBBC), nicotinamido (NABBC), and 3‐methylpyridinium (3‐PBBC) cationic groups were synthesized and characterized by ¹H NMR and HPLC–mass spectrometry. They were then applied to cotton fabric in a bleaching process and evaluated for their performance against the prototype N‐[4‐(triethylammoniomethyl)benzoyl]butyrolactam chloride (TBBC) at a relatively low bleaching temperature (55 °C) and pH 8.5. Measurement of Commission internationale de l’éclairage (International Commission on Illumination) (CIE) whiteness index (WI) values showed that PBBC (WI = 64), NABBC (WI = 58), and 3‐PBBC (WI = 71) impart a significant increase in CIE whiteness compared to a control sample (WI = 40). Among the three new activators, 3‐PBBC exhibited the best performance. Its WI was comparable to that of fabric bleached using the prototype bleach activator TBBC. The acute toxicity of TBBC and the new bleach activators was evaluated using the microcrustacean Daphnia similis. The chronic toxicity of TBBC and 3‐PBBC was evaluated using the green alga Raphidocelis subcapitata, and mutagenicity was evaluated in the Salmonella/microsome assay using the strain TA100. 3‐PBBC was 86 times less toxic to D. similis, 18 times less toxic to R. subcapitata, and 10 times less mutagenic to TA100 in comparison with TBBC.     

Use of standing bath technique in peroxide bleaching of cotton

The use of a standing bath technique in hydrogen peroxide bleaching of cotton fabric was investigated. Two non-silicate stabilisers, a laboratory-formulated inorganic stabiliser and a commercial organic stabiliser, were used. The bleaching recipe was optimised for maximum whiteness and then used for the standing bath technique by replenishing the bath with the equivalent peroxide concentration and maintaining the pH. The level of replenishment of the stabiliser was varied up to 70% of the initial amount of stabiliser. The results, as assessed by CIE whiteness index, indicate that it is only possible to achieve similar whiteness levels to bleaching without a standing bath by replenishing the stabiliser with a large proportion of the original amount.