Process Optimization For Bleaching of Banana Fibers

Journal of Research Updates in Polymer Science, 2018

The article highlights some recent trends in the bleaching of textile materials. An attempt has been made to compare the effect of electrochemical bleaching with conventional bleaching of cotton. Electric current is used in the preparation of a bleaching agent to replace bleaching powder. The sodium hypochlorite generated from electrolyte cell is sufficient to produce powerful bleaching agent with available chlorine. Electrochemical bleaching with sodium hypochlorite offers numerous advantages like prevention of effluent problem, economy, reliability, cleanliness, and convenience in working. Attempts have been made to use sodium perborate as a bleaching agent with potassium persulphate as an activator at lower temperature in combined pre treatment of cotton fabric. Experimental trials have been designed by using taguchi technique. This bleaching technique promises to be eco-friendly process. In yet another interesting work, effort has been taken to bleach the scoured cotton fabric with sodium perborate as bleaching agent and tetreacetyl ethylenediamine as bleaching activator. The concentrations of these chemicals, temperature and time of the treatment have been varied. The utilization of hydrogen peroxide is much higher as compared with that of conventional bleaching process. Other advantages include less requirement of water and energy, thereby satisfying needs of ecofriendly process, lesser loss in weight, tearing strength, and tensile strength, in comparison with conventional bleaching process without compromising whiteness index.

2017

Fibres have been extracted from fruit and bunch stems of banana plant by water retting and evaluated in terms of their performance characteristics. Banana bunch stem fibres have been found to be superior in terms of fineness, initial modulus and breaking strength, whereas elongation ratio shows an inverse trend. Thus, they have been further treated by bleaching and alkalization. Among the treated fibres, the bleached fibres show the highest initial modulus, breaking tenacity, and the lowest elongation. Alkalization results in increased breaking elongation and decreased initial modulus, whiteness and water absorption. The bunch stem fibres present higher water absorptive capacity and lower whiteness compared to that of fruit stem fibres. The characteristics of these unconventional fibres have been found to be comparable to natural fibres traditionally used in textiles. The ranges for properties of the studied banana fruit and bunch stem fibres in general can be given as: linear densi...

A novel chemical formulation for bleaching flax fibers (machine tow) in one-step process was established. The process is basedon activation of sodium chlorite by hexamethylene tetramine (HMTA) in the presence of a nonionic wetting agent. The factors affecting the bleaching such as HMTA concentration, temperature, and duration of the treatment were studied to optimize the bleaching conditions. The bleached flax fibers were assessed for critical properties; namely, whiteness index, loss in fiber weight, tensile strength, carboxyl groups, and carbonyl groups. Based on the results obtained the optimum formulation for bleaching the flax fibers is consisting of: [NaClO2] = 5 g/l, [HMTA] = 0.25 g/l and [wetting agent] = 1 g/l provided that bleaching is carried out at 90°C for 3 hrs using a material-to-liquor ratio (M/L) of 1:50. For comparison purposes, different types of flax fibers; namely, grey, card, and waste fibers were bleached under the optimum bleaching conditions of the machine tow flax fibers, and their properties after bleaching were also examined. Furthermore, tentative mechanisms for the reactions involvedin bleaching using NaClO2/HMTA system were suggested. It seems that, when the optimum formulation was used, HMTA activates decomposition of NaClO2 to mainly liberate nascent oxygen rather than chlorine dioxide

BioResources, 2022

There is a need for sustainable ways of processing plant fibers. Most chemical degumming methods pose a threat to the ecosystem because of the presence of toxins during disposal. This study aimed to find sustainable ways of processing banana fiber with less harm to the environment. Sodium hydroxide (NaOH) and activated water were utilized for degumming and softening of the banana fiber. Activated water is an aqueous solution of electrolyte with strongly oxidizing active substances prepared by an electrochemical method. The alkali-pretreated banana fiber were immersed in activated water to refine banana fiber. The results from the study show that activated water further refined the fibers down to 39.7 µm diameter after NaOH pretreatment and also achieved better whiteness at 74.7%. The electrochemically activated water solutions displayed a promising effect in removing lignin, hemicellulose, and other impurities. The fibers of this quality could be used in the spinning of yarn and for other textile applications. Various analytical techniques, including digital microscope, scanning electron microscope, Fourier transform Infrared spectroscopy, X-ray diffractometry, tensile test, and whiteness test were utilized. These tests confirmed that the activated water used on banana fiber enhanced physical, chemical, and morphological properties.

The study comprises the effect of different bleaching parameters on scoured single jersey cotton fabrics. Three different concentrations (1.8 g/L, 2.0 g/L and 2.2 g/L) taken from 5% stock solution of hydrogen peroxide were considered for the experiment. In each concentration, bleaching was performed in four individual temperatures (78�C, 88�C, 98�C and 108�C). In each of the temperatures bleaching were continued for four individual time period (20, 30, 40 and 50 minutes). The weight of sample fabric was 12.5 grams and 1:10 liquor ratio was maintained in each operation. The bleached samples were tested in a reflectance spectrophotometer (datacolor 650) and also their bursting strengths were found from an Autoburst instrument following ISO 13038-1 method. The results show that bursting strength and whiteness index have an inverse relation between themselves. For the nominated concentrations of peroxide, 88�C to 98�C temperature with 30 to 40 minutes time duration is suggested as the o...

The aim of this study is to evaluate environment supportive pretreatment and dyeing process. In this project, pretreatment of cotton fabric was done by using banana ash. Also, dyeing was carried out with banana sap along with different mordants that are eco-friendly and cost saving. Here, all the experiments were carried out on woven (plain) fabric of 141 GSM. Firstly, cotton fabric was scoured by means of banana root's ash (pH-10.2). It was then dyed with banana sap (pH-5.4). This banana ash scoured cotton fabric was compared with conventionally scoured cotton fabric through weight loss % and absorbency test. In addition, fastness properties and performance of dyeing were measured through CIE L*C*h, K/S value, and different color fastness tests. Banana ash scoured and dyed with banana sap, using mordant (horitoky), provided the best dyeing performance and color fastness to wash, rubbing, and perspiration than the others.

Cellulose, 2010

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.

Bleaching of cellulose material with hydrogen peroxide (H2O2) is carried out, in general, beneath alkaline stipulations at excessive temperature, which ends up in bigger energy consumption and fibre damage. This study was designed to achieve bleaching of cotton material at low temperature by utilising sodium persulfate (Na2O8S2), which is a catalyst of hydrogen peroxide decomposition, to improve the traditional procedure. The variables affecting bleaching effects were investigated; the bleaching temperature was confirmed to have the greatest influence on activated bleaching, and the elevated temperature used was accompanied by tremendous improvement in whiteness. The whiteness index of the fabric bleached at low temperature was lower than that of fabric bleached at high temperature, but the tensile strength and weight loss were a lot better for the material bleached at low temperature. Subsequent Fourier transform infrared analysis indicated that the potassium persulfate/hydrogen peroxide bleaching system decreased carbonyl groups better than traditional bleaching did, leading to greater bleaching efficiency and final brightness. Bleaching by potassium persulfate/hydrogen peroxide resulted in stronger oxidation than by hydrogen peroxide bleaching. By calculating through a theoretical energy consumption analysis, it was found that the low-temperature process required 1·96 times lower energy than that for the traditional procedure.

Turkish journal of analytical chemistry, 2023

Traditional textile bleaching techniques need to be given another look in light of the environment and lifestyle of today. To achieve higher whiteness values while using less water and chemicals during the bleaching process, it is crucial for both the environment and the economy. The most effective disinfectant, chlorine dioxide (ClO2), is produced by sodium chlorite (NaClO2), which is a suitable oxidant for the job. During the COVID-19 pandemic, NaClO2 gained popularity and became more widely available. The use of NaClO2 as a bleaching agent offers many benefits, including a decrease in the number of washing steps and an increase in cotton strength. This reagent's ability to produce less weight loss in the fabric than other reagents is another benefit. Therefore, the present work was intended to improve the process conditions (different temperatures, concentrations, and times) of bleaching of cotton fabric by using NaClO2.A high whiteness index (W.I. = 88) was obtained by utilizing phosphonic acid (HEDP), and the ideal temperature and duration were found to be 30 min at 65 °C and 30 min at 85 °C. Moreover, the tensile strength, weight loss and morphologies of the samples were examined. Because sodium chlorite does not leave behind any alkaline residues, it has been found to do less harm to cotton fibers and use less water for rinsing.

Journal of Fiber Science and Technology, 2021

Bleaching is the most important pretreatment process commonly used in coloration industry for removing natural colorants and impurities of fiber prior to dyeing and finishing [1]. One of the oldest industrially bleaching chemicals is hypochlorite [2]. Although hypochlorite bleaching offers some advantageous effect, but it has been discouraged due to the formation of highly toxic chlorinated organic byproducts (AOX) during the bleaching process [3]. Another most important bleaching agent is hydrogen peroxide, which is commonly used for cellulosic fibers under alkaline conditions. The dissociation of hydrogen peroxide increased with rising temperature and form perhydroxyl anion shown in scheme 1[4]. Perhydroxyl ions (HO2-) demobilize the mobile electrons of conjugated double bonds in chromophores and caused decolorization [5]. However, hydrogen peroxide bleaching process required high temperature and long processing time, which leads to higher energy consumption and increased fiber damage [6]. The decomposition of H2O2 by the hydroperoxide anion provides per hydroxyl radical that oxidized the cellulose. In an alkaline solution, the perhydroxyl radical attacks the C2 and C3 atoms of cellulose, which form inactive carbonyls shown in scheme 2 [7].