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Schematic illustration of change in crystallinity of ramie fibers modified in liquid ammonia and aqueous medium
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Anhydrous liquid ammonia was used as a solvent for the cationic modification of ramie fiber using 2, 3-epoxypropytrimethylammonium chloride (EPTAC). The processing parameters, including treatment temperature, treatment time, concentration of EPTAC, and concentration of NaOH were schematically investigated in order to control the properties of the f...
Citations
... Cationic modification of cellulosic fibre is an alternative process to improve its dyeability (Lewis and Mcllroy, 1997;Montazer et al., 2007;Nallathambi and Venkateshwarapuram Rengaswami, 2016). EPTAC (2, 3-epoxypropytrimethy-lammonium chloride) and CHPTAC (3-chloro-2-hydroxypropyltrimethyl ammonium chloride) are common cationic agents for pre-treating cellulosic fibres, including treating ramie fibre in water (Cai et al., 2014;Liu et al., 2007;Naikwade et al., 2017) and liquid ammonia (Cai et al., 2018b;Su et al., 2019). After cationic modification, part of the hydroxyl groups (-OH) of cellulose are changed to the cationic group (-NH 3 + ), which apparently increases dye exhaustion, even without the addition of salt for dye promotion. ...
... The FI-IR spectra of OF, AIBF@OPT, and CMF are presented in Fig. 10. A pronounced and wide band spanning the range of 4000-3000 cm − 1 , evident in all spectra, can be attributed to the stretching of hydrogen-bonded OH groups (Cai et al., 2018b;Oh et al., 2005). The CH stretching peak at 2900 cm − 1 (characteristic of Cellulose I) (Hu et al., 2017;Moharram and Mahmoud, 2008) shifted to 2893 cm − 1 (Cellulose II). ...
The high crystallinity of ramie fibre poses challenges in achieving optimal dyeing performance, such as reduced dye exhaustion. To enhance the dyeing capabilities of ramie fibre, several alterations were experimented with, such as caustic mercerization using a NaOH solution. However, because of the high NaOH concentration, removing the NaOH residue from inside the fibre becomes challenging. Herein, the present research aims to enhance the dyeing efficiency of ramie fibre by using sequential alkaline and alcohol pretreatment methods to reduce NaOH usage, accordingly relieving the wash process stress. The preliminary screening findings have revealed that iso-butanol is the most suitable alcohol solvent for modifying ramie fibres after treating it with NaOH solution since it leads to higher dye exhaustion (E%, 95.7%), dye fixation rate (F%, 88.2%), total dye fixation efficiency (T%, 84.4%), and K/S values (41.4). After that, the orthogonal array experimental scheme (L16) was applied to optimize dyeing performance. The NaOH usage was decreased to 160 g/L, the treating time was reduced to 3 min, and the dyeing performance of ramie fibre treated under the optimum conditions was better than that of a caustically mercerized one. It was determined that the NaOH concentration factor had the most contribution, accounting for 75.34% of the observed effects. The NaOH solution temperature factor followed closely behind, contributing 22.69%. Additionally, using analytical methods such as XRD, FTIR, TG, and SEM confirmed that the sequential treatment with the optimum conditions altered the structural behaviour of the original ramie fibre, which performances were similar to the mercerized ramie fibre. The barium value of sequentially iso butanol solvent treated fibre showed a greater level (213) compared to caustic mercerized fibre (179), indicating a significant advantage of mercerization performance was achieved. This advantage may be linked to improved colourfastness and handling qualities. Furthermore, the breaking force of both ramie fabrics was increased after the alkaline treatment and the sequential alkaline and iso-butanol treatment.
... In order to improve the dyeing performance of ramie fibre, pre-treatment of ramie fibre was usually applied, and the primary processes include cationic modification [7][8][9][10][11][12][13][14] and mercerisation [9,[15][16][17][18][19][20]. The main compound of ramie fibre is cellulose, and the cationic modification of ramie is to introduce a cationic group in the fibre, which is covalently reacted with some hydroxyl groups of the cellulosic ramie fibre. ...
... The XRD patterns of raw ramie fibre (RF), the caustic mercerised ramie fibre, and the ramie fibre treated under optimal conditions are shown in Fig. 10. The XRD pattern of RF (Fig. 10a) displays the characteristic peaks of cellulose I, whose 2 θ are 15.0, 16.6, 22.7, and 34.6 • [8]. With the caustic pre-treatment, the cellulose I of ramie fibre was transferred to cellulose II, whose characteristic peaks are 2 θ of 12.3, 20.4, ...
... The FT-IR spectra of RF, CMF, and IPF@OPT are shown in Fig. 11. A strong, broad band of about 4000-3000 cm − 1 observed in all the spectra is attributed to the hydrogen-bonded OH stretching [8,12,35]. The CH stretching at 2900 cm − 1 (cellulose I) [36,37] was shifted to 2893 cm − 1 (cellulose II), and the absorption band at 898 cm − 1 (cellulose I) of RF spectrum was shifted to the lower wavenumber at 893 cm − 1 (cellulose II) of CMF and IPF@OPT fibres' spectra. ...
Deep shade dyeing of ramie fibre is challenging due to its high degree of polymerisation, orientation, and crystallinity. The present work involved pre-treating ramie fibre with a solution containing a mixture of NaOH and alcohol in order to improve its dyeing ability. Based on the first screening results, it has been shown that iso-propanol is the optimal alcohol solvent for modifying ramie fibres with a mixture of NaOH solution, resulting in greater levels of dye exhaustion (E%), dye fixation rate (F%), total dye fixation efficiency (T%), and K/S values. Subsequently, the orthogonal array experimental technique (L16) was utilised to optimise the treatment conditions, and it was determined at a temperature of 25 °C, using a NaOH solution with a concentration of 140 g/L, a liquid ratio of 1:2 for the volume ratio of NaOH solution to iso-propanol solvent, and a treating period of 3 min. The treated samples were subjected to a range of analytical techniques, including XRD, FTIR, TGA, and SEM; these analyses conclusively verified that the samples' properties were altered due to the optimal combination treatment. The combination solution-treated samples had significantly higher barium values compared to the other samples, suggesting an ideal mercerisation treatment. The colourfastness to washing values exhibited satisfactory results for the treated samples. Besides, a handle assessment of raw ramie fabric and treated ramie fabric was conducted to enhance the practical application feasibility.
... It is reported in the scientific literature that the use of the cationization technique before dyeing cellulosic fibers increases dye fixation, resulting in stronger colors and a reduced number of wash cycles after dyeing [17,18]. ...
The purpose of this study was to functionalize a bleached and cationized jute fabric with a thermochromic agent and apply it as reinforcement into a crystal polyester resin matrix, forming a smart composite capable of thermally reacting to the environment in which it is inserted. Functionalization was favored in cationized fabric and the presence of the thermochromic on jute fibers was confirmed by Fourier Transform Infrared Spectroscopy (FTIR) analysis and Scanning Electron Microscopy (SEM). Functionalization increased the thermal degradation temperature of the jute fabric but does not alter the thermal behavior of the composite. Through reflectance spectrophotometry analysis, L*, a*, and b* coordinates of the bleached and functionalized fabrics were observed. The K/S value for the functionalized fabrics and composite samples was analyzed after 1, 15, and 30 days, showing a higher color strength for the composite. With this, it was demonstrated that is possible to create a smart composite reinforced with functionalized jute fabric, allowing its use in several areas of application.
... 43 The attachment of EPTAC on VAR can take place after deprotonation of either the amide groups of its Kevlar component or/and the alcohol groups of its cellulose component with a base (NaOH), followed by a nucleophilic attack of the Kevlar-or cellulose-based anions on EPTAC's epoxide, resulting in the epoxide's opening. 44 Following this modification of VAR, its surface acquires trimethylammonium moieties that induce antibacterial properties. ...
The present work focuses on the surface coating of VAR technical fibers, consisting of 64% viscose (cellulose), 24% Kevlar, 10% other types of polyamides, and 2% antistatic polymers. Kevlar is an aramid material exhibiting excellent mechanical properties, while cellulose is a natural linear polymer composed of repeating β-d-glucose units, having several applications in the materials industry. Herein, we synthesized novel, tailor-designed organic molecules possessing functional groups able to anchor on VAR fabrics and cellulose materials, thus altering their properties on demand. To this end, we utilized methyl-α-d-glucopyranose as a model compound, both to optimize the reaction conditions, before applying them to the material and to understand the chemical behavior of the material at the molecular level. The efficient coating of the VAR fabric with the tailor-made compounds was then implemented. Thorough characterization studies using Raman and IR spectroscopies as well as SEM imaging and thermogravimetric analysis were also carried out. The wettability and water repellency and antibacterial properties of the modified VAR fabrics were also investigated in detail. To the best of our knowledge, such an approach has not been previously explored, among other factors regarding the understanding of the anchoring mechanism at the molecular level. The proposed modification protocol holds the potential to improve the properties of various cellulose-based materials beyond VAR fabrics.
... According to an estimation by the World Bank, conventional textile dyeing and finishing processes account for 17 to 20% of industrial water pollution (Holkar et al. 2016;Kant 2012). The effluent, generated from conventional aqueous dyeing of cotton with reactive dye, mainly consists of inorganic salts and alkalis, hydrolyzed dyes and auxiliaries (Khatri et al. 2015), causing detrimental effect on the ecosystem, aquatic species and human health (Bhatia et al. 2017;Cai et al. 2018). ...
Reactive dyes of three primary colours used for exhaustion dyeing of cotton fabric in conventional water dyeing system and APG-based reverse micelle dyeing system, with D5 and alkane solvents as dyeing medium, were investigated. Calibration curves of both systems were established. Absorbance and dye concentration were found to be directly correlated with each other. The curves exhibited high linearity with R² above 0.99, validating their suitability for subsequent SERF measurement. The values of substantivity factor (S), exhaustion factor (E), rate of fixation (R) and fixation factor (F) were measured and calculated in percentage. The results revealed that APG reverse micellar dyeing system obtains higher S and E, but lower R and F values than the conventional water dyeing system, verifying excellent final dye exhaustion and good leveling properties of the APG reverse micellar dyeing system when compared with the conventional aqueous dyeing system. The use of D5 and alkane solvents as dyeing medium causes no significant effect on the establishment of SERF profile in APG reverse micellar dyeing system.
Graphical Abstract
... The zeta potential is a function of the surface chemical composition of the fiber, the type of the cationic agent and the concentration of the cationization process. Cai et al. (2018) measured the zeta potential for cationic ramie fibers. The authors performed the analysis solely at pH 7, varying the CHPTAC concentration between 0 and 20 g L -1 and bath temperature of 40 or 60°C. ...
Eight molecules with D-π-D molecular motifs coded HTM(1-4)a,b were designed as efficient symmetric hole transporting materials for perovskite solar cells. These HTMs are composed of different core moieties, such as spiro [fluorene-9,9′-xanthene]-diol (SFO), spiro [fluorene-9,9′-xanthene]-dimethoxy (SFM), benzo [c][1,2,5]thiadiazole (BTD), and biphenyl (BP) and are gaining lot of attention because of their low-cost, reproducible electrical and optical properties in device performance. Detailed information about the energetic of molecular levels (GSOP/ESOP), first singlet excitation energy (E0-0), equilibrium molecular geometry, charge separation, charge transfer, reorganization energies, polarizability and hyperpolarizability, density of states (DOS), solubility and stability of these molecules was attained by systematically performing molecular modeling calculations using density functional theory (DFT) and time dependent-DFT calculations utilizing hybrid density functional B3LYP using the basis set 6–31g(d,p) level of theory as a successful method for predicting the photophysical and photovoltaic properties of these conjugated systems. The results showed that not only the core moieties, but also Schiff-base linkage extended conjugation, have an effect on the photophysical and photovoltaic properties of the proposed HTMs. It was demonstrated that HTMs incorporating SFO (HTM1a,b), SFM (HTM2a,b), and BP (HTM4a,b) achieved better charge transport, high stability values ( a = 2.11–2.40 eV), low electron-hole binding energy (Eb = 0.16–0.21 eV) than HTM3a,b with BTD core, which improves hole mobility and decreases recombination, all of which improved device photocurrent, which can be attributed to the extended π-conjugation in SFO, SFM and BP cores. These findings are strikingly similar to those of Spiro-OMeTAD ( a = 2.45 eV, Eb = 0.16 eV), indicating that these HTMs are promising candidates for efficient and cost-effective PSCs. Interestingly, when the stability of HTM(1-4)a and HTM(1-4)b was compared, it was clear that HTM(1-4)a has lower stability than HTM(1-4)b, which could be attributed to the presence of Schiff base Cdouble bondN bonds in HTM(1-4)b, which reduces the molecules stability when compared to HTM(1-4)b, owing to a strong C–C linkage. Meanwhile, HTM(1-4)a outperforms HTM(1-4)b in terms of electronic performance and hole mobility.
... In a bid to reduce the use of water and the risk of effluent discharge in the textile industry, researchers have achieved several developments, such as liquid ammonia dyeing [3][4][5][6][7], decamethylcyclopentasiloxane (D5) dyeing [1,[8][9][10][11], nanoparticles dyeing [12][13][14], cottonseed oil dyeing [15], air-jet dyeing [16], gas-liquid dyeing [17] and foam dyeing [18]. To eliminate water consumption, the technology includes organic solvent dyeing [19], vacuum sublimation dyeing [20], and supercritical carbon dioxide dyeing [21]. ...
Anhydrous liquid ammonia treatment and dyeing are introduced in this review paper. The dyeing mechanism was a two-stage process. Dyeings carried out in anhydrous liquid ammonia produced an unlevel colour problem, but it could be largely improved using co-solvent dyebath (ammonia/alcohol or ammonia/water) instead of anhydrous liquid ammonia. The washfastness of the dyed sample by aminoplast resin treatment was similar to that of samples conventionally dyed in water, followed by a resin treatment. This review aims to report the anhydrous liquid ammonia dyeing technology, a dyeing technique for reducing or eliminating water consumption. Also, its advantages, including dyeing time reduction, energy saving, economically viable and eco-friendly advantages, and conventional dyestuffs serviceable, are discussed in this review paper. With the equipment technology development, the limiting factor of wider exploitation of this technique which is the high capital cost of the machinery for recovery of ammonia which involves refrigeration, can be resolved. Consequently, an anhydrous liquid ammonia dyeing technique attracts dyeing factories again
... The treatment process was completed in a rotary infrared radiation laboratory-dyeing machine (Automatic Prototype, Model: A-12, AQUA, China). The dye solution at various treatment periods was measured using a UV-Vis spectrophotometer (Cary 100, Agilent Technologies, Australia) 38 . The degradation percentage of dye (D%) was calculated using Eq. ...
Natural materials, especially natural colorants, have achieved global prominence and might be regarded as an environmentally beneficial alternative to hazardous synthetic dyes. The color limitation of natural dyes hinders their application in textiles. The present work aims to prepare more color shades of wool yarns via dyeing with ternary natural dye mixtures without adding mordants. In this study, a sustainable dyeing approach for wool yarn was evaluated with three natural dyes, madder red (MR), gardenia blue (GB), and gardenia yellow (GY), by following an industrial dyeing procedure in the absence of a mordant. In the beginning, a preliminary assessment of dye stabilities was carried out, and it was found that the three natural dyes were sensitive to temperature and acid (degradation tendency). Then, the dyeing behavior was systematically evaluated, including a single natural dye, a binary natural dye mixture, and a ternary natural dye mixture. The results of wool yarn dyeing with a single natural dye show that the dye exhaustion percentage (E%) of MR, GY, and GB was in the ranges of 78.7–94.1%, 13.4–44.1%, and 54.8–68.5%, respectively. The dyeing results of wool yarns dyed with binary and ternary natural dye mixtures (a color triangle framework of dyed wool yarn) were characterized by colorimetric values (L*, a*, b*, C*, h, and K/S), and are presented to enlighten various colorful shades. Finally, color uniformity and colorfastness tests confirmed the vital contribution of natural dyes toward wool yarn coloration. Particularly, colorfastness to washing confirmed the stability of natural dyes with reference to the lower amount of dyes released into the effluent, which is beneficial for the environment. Overall, this study provides a good background for enhancing the industrialization trend of natural dyes by modulating their dyeing scheme.
... Textile dyeing industry has long been labelled as one of the largest water consumers and effluent producers in the world [1,2]. Conventional dyeing of cotton fibre with reactive dyes requires large amount of auxiliaries to promote exhaustion (absorption) and fixation [3][4][5][6] while producing substantial amount of coloured effluent, which comprises hydrolysed dyes, inorganic salt and alkali, and other chemicals [7][8][9], causing environmental stress as huge amount of chemical auxiliaries discharged into aquatic environment which eventually affect the human health and biodiversity in water bodies [10][11][12]. ...
The viability of reverse micelles, using rhamnolipid (RL) microbial biosurfactant as the building block, for dyeing of cotton fabrics with reactive dyes has been studied. This novel and sustainable dyeing system not only can achieve salt-free, but also alkali-free under optimised dyeing parameters. Experimental results reveal that RL-based reverse micellar dyeing system can be achieved in one-bath one-step dyeing approach, which is environmentally friendly, time and energy saving, with better colour yield, lower reflectance when compared with conventional water-based dyeing system. RL-dyed samples can obtain comparable colour levelness, washing and rubbing fastness to water-dyed samples. No significant chemical damage of cotton fibre surface was observed from scanning electron microscopic (SEM) investigation. The dye-encapsulated reverse micelle was justified as spherical-like morphology from transmission electron microscopic (TEM) observation. The outcome of the study validates the potential and applicability of RL, as a substitute of synthetic surfactant, in non-aqueous reactive dyeing of cotton fabrics.
... Recently, waterless dyeing of cellulosic bres became a hot research topic, which uses a non-aqueous medium where the solvent can be recycled and reused for successive dyeing. Various solvents, such as liquid ammonia, [19][20][21][22][23] decamethylcyclopentasiloxane or D5, 24-28 cottonseed oil, 29 and supercritical carbon dioxide 30 as an alternative to the aqueous medium. In liquid ammonia dyeing, the colouration and mercerisation of cellulosic bres are achieved simultaneously. ...
Traditional grass cloth has been used in China for a long time for the manufacturing of various household furnishing textiles and ladieswear.
