Bio-Dyes, Bio-Mordants and Bio-Finishes: Scientific Analysis for Their Application on Textiles

This chapter deals with testing/characterization and other scientific analyses and process standardization for the application of bio-dyes, bio-mordants, and bio-finishing agents on cotton textiles. Few case studies on selective natural/bio-dyes in terms of Fourier-transform infrared spectroscopy (FTIR), high-performance liquid chromatography (HPLC), ultraviolet–visible (UV–VIS) spectroscopy, and differential scanning calorimetry (DSC) analysis have been discussed. Based on these characterizations, few test protocols have been established for the identification of each natural dye from dyed textiles, as standards of Bureau of Indian Standards (BIS). One such case study on madder is shown. Exemplary case studies on the standardization of extraction, suitable mordanting, and dyeing process variables for the application of specific natural dyes on cotton have also been provided. Few case studies on improving color fastness to washing and sunlight by suitable post-treatment with natural agents have been discussed. Case studies on different post-treatments/simultaneous dyeing and finishing treatments with bio-dyes and bio-finishing agents for improving antibacterial properties and UV protection factor (UPF) have also been explained

Optimization of antimicrobial finishing on cotton muslin fabric by treatment with PEG, chitosan and cetrimide

In the present work, combinations of different concentrations of binary mixture of chitosan + PEG, chitosan + cetrimideand PEG + cetrimide have been applied on bleached cotton muslin fabric by pad-dry-cure process in the presenceof citric acid + sodium hydrogen phosphate catalyst, and the consequent percentage strength retention aftertreatment, percentage strength retention after soil burial test and average bacterial reduction % are evaluated with an aim tooptimize the concentrations of chitosan, polyethylene glycol and cetrimide to achieve a balance between antimicrobialproperties and tenacity retention. Optimization results show that the application of 2% chitosan + 2% PEG (50:50) withcitric acid and SHP as mixed catalyst system gives shows very good antimicrobial/ rot resistant properties without much loss of tenacity

Compatibility of binary mixture of natural dyes for developing compound shades for cotton khadi fabric

The compatibility rating of any two natural dyes applied together for obtaining compound shade has been determined. The natural dyes selected for compatibility study are, babool (BL), pomegranate rind (PR), madder or manjistha (MJ), red sandal wood (RSW), tesu flower (TF) and catechu (CT) based on their maximum commercial use. The dyes have been extracted in aqueous medium under optimized conditions and their binary mixtures in different proportions are used to dye cotton khadi fabric for developing varying compound shades on 15% overall concentration of myrobolan (harda) and aluminium sulphate (75:25) in sequence double pre-mordanted cotton khadi fabric. After dyeing with binary mixtures of natural dyes , dyed cotton fabric samples are subjected to evaluation of K/S, colour differences (∆E), colour difference index (CDI) values; changes in hue /chroma, brightness index (BI), metamerism index (MI) etc; and also colour fastness to washing, light, rubbing and perspiration. The compatibility of these binary pairs of natural dyes has been assessed conventionally (∆c vs ∆L and K/S vs ∆L), as well as using an unique and simple novel method of compatibility test applied for assessing relative compatibility rating (RCR) of each binary pairs of natural dyes, by evaluating colour difference index [(∆E x ∆H) / (∆C x MI)] for application of different proportion of two dyes in each binary pair. The results of this novel simple method are found mostly in well agreement with the findings of compatibility test by conventional methods. Finally, the order of relative degree of compatibility of these binary pairs of natural dyes is found to be BL: MJ > BL: RSW > BL: CT > BL: PR > BL: T

Compatibility of binary mixture of natural dyes for developing compound shades for cotton khadi fabric

158-167The compatibility rating of any two natural dyes applied together for obtaining compound shade has been determined. The natural dyes selected for compatibility study are, babool (BL), pomegranate rind (PR), madder or manjistha (MJ), red sandal wood (RSW), tesu flower (TF) and catechu (CT) based on their maximum commercial use. The dyes have been extracted in aqueous medium under optimized conditions and their binary mixtures in different proportions are used to dye cotton khadi fabric for developing varying compound shades on 15% overall concentration of myrobolan (harda) and aluminium sulphate (75:25) in sequence double pre-mordanted cotton khadi fabric. After dyeing with binary mixtures of natural dyes , dyed cotton fabric samples are subjected to evaluation of K/S, colour differences (∆E), colour difference index (CDI) values; changes in hue /chroma, brightness index (BI), metamerism index (MI) etc; and also colour fastness to washing, light, rubbing and perspiration. The compatibility of these binary pairs of natural dyes has been assessed conventionally (∆c vs ∆L and K/S vs ∆L), as well as using an unique and simple novel method of compatibility test applied for assessing relative compatibility rating (RCR) of each binary pairs of natural dyes, by evaluating colour difference index [(∆E x ∆H) / (∆C x MI)] for application of different proportion of two dyes in each binary pair. The results of this novel simple method are found mostly in well agreement with the findings of compatibility test by conventional methods. Finally, the order of relative degree of compatibility of these binary pairs of natural dyes is found to be BL: MJ > BL: RSW > BL: CT > BL: PR > BL: TF

Why pandemic coronavirus (SARS-CoV-2) hit different age groups of people in Southeast Asia? a case study in Bangladesh

The new catastrophe of a novel coronavirus (COVID-19s) with unstable symptoms has rapidly pulled danger to all age groups worldwide. We investigate possible causes of the different nature and demography of COVID-19. We collected and used secondary data from the IEDCR website and “Worldometer” from 1st April to 24th June for the statistical analyses, including multi-criteria decision-making method (MCDM), topsis, advanced topsis, simple additive weighting (SAW) and weighting product method (WPM) and PCA. The total number of known COVID-19 patients in Bangladesh was 122,709 as of 24th June. Radical growth will be found with 4912 cases in one day on 16th July as per the time-series forecasting. The infection rate among the young (<30) was highest, i.e., 37.8%, while the elderly (>60) had the maximum death rate (≈39%). Both of India and Bangladesh, approximately one-third of total COVID-19 cases belong to the under 30 age group. Preliminary observation finds India and Bangladesh have a high risk for young people and the working class. PCA indicates the highest positive association among the youths and the highest negative association among the older. In this study, older age (>60) individuals are in danger with the fifth rank, and the young and working-age people are at comparatively lower risk with a third to the fourth rank in terms of infection rate as indicated by MCDM. 41-50 age group remains at lower risk with the first rank in all cases. The nature of activities of younger people and the poor immunity system of older people are the reason for the non-homogenous attitude toward the coronavirus among different age groups. In Bangladesh, drug addiction, gambling habits, uncontrolled lifestyle, and social obliquity have led the youth through danger, threatening the older age of family and society

Colorimetric Evaluations and Characterization of Natural and Synthetic Dyes/Pigments and Dyed Textiles and Related Products

This book chapter covers principles and few case studies on colorimetric Estimation of (i) determining purity/active ingredient % of selective dyes/pigments (ii) Identification of any colorants to distinguish from other similar compound, (iii) Measurement of surface colour strength of a dyed textile, (iv) Measurement of colour differences by estimating DE, DL*, Da*, Db*, DC and DH values, (v)Computer-aided colour match prediction for any standard shades, (vi) Estimation of compatibility of two dyes/colourants to use for compound shades, (vii) Determination of rate of dyeing, dyeing isotherm and dyeing kinetics to control dyeing, (viii) Optimization of dyeing process variables, (ix) Precession grading of Colour Fastness of dyed textiles on fading under different ways/agencies and (x) Estimation of Soil Removal efficacy of different detergent used for textiles. These colorimetric measurements are found to be very useful for effective process and product control of dyed textile materials. Selected Case studies on all the above colorimetric applications with specific example or experimented data are discussed for each of the method under reference. Finally, the other applications of colorimetric analysis besides textiles industry are also mentioned in concluding remarks

Dyeing of jute and cotton fabrics using Jackfruit wood extract: Part I — Effects of mordanting and dyeing process variables on colour yield and colour fastness properties

466-476Conventionally bleached jute and cotton fabrics have been subjected to pre-mordanting with selective single and double mordants using myrobolan (harda) and other mordants (metallic salts) followed by dyeing with aqueous extract of jackfruit wood and then studied for their mechanical and dyeing properties. It is observed that the application of 10-20% myrobolan followed by 10-20% of Al₂(SO₄)₃ or FeSO₄ in sequence have been identified as two most prospective mordanting systems. The study on the effect of dyeing process variables on surface colour strength indicates that the 90 min dyeing time, 70-90ºC dyeing temperature, 11.0 pH, 1:30 material-to-liquor ratio, 20-30% mordants concentration, 30-40% dye concentration, and 15 gpl common salt are the optimum values with minor differences among the different fibre-mordant systems studied. Colour fastness to washing, rubbing and exposure to sunlight, in general, and dyeing-pH sensitivity, in particular, for selective fibre-mordants-dye systems have also been assessed and compared. Dyeing at pH 11.0 for both the double pre-mordanting systems offers overall good colour fastness properties

Application of natural dyes on textiles

384-399This paper reports the studies available on the characterization and chemical/biochemical analysis of natural dyes; extraction of colorants from different natural sources; effects of different mordants and mordanting methods; conventional and non-conventional methods of natural dyeing; physico-chemical studies on dyeing process variables and dyeing kinetics; development of newer shades and analysis of colour parameters for textiles dyed with natural dyes; and test of compatibility for application of binary mixture of natural dyes. The chemical modification of textile substrate for improving dyeability, attempts for improvement in overall colour fastness properties and survey of some traditional processes of natural dyeing in different parts of India have also been discussed