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While cationic cellulose has yet to find a place in the paper industry, manufacturers show certain interest in a more recent material: cellulose nanofibers (CNFs), generally with negative surface charge. This work suggests both to be combined to increase the mechanical properties of recycled paper while preventing the use of synthetic polyelectrolytes as retention agents. On one hand, a bleached pulp was cationized by etherification, both as-is and following mechanical refining (15,000 PFI revolutions) and submitted to high-pressure homogenization, generating two different kinds of cationic CNFs. On the other, the same pulp was submitted to an enzymatic pretreatment and high-pressure homogenization, producing a negatively charged cellulose micro/nanofiber (CMNF). Two different cellulose-based systems consisting of each type of cationic CNF and the enzymatic CMNF were applied in the papermaking of both virgin and recycled paper. This study demonstrates the effective use of the cationic CNFs as retention agents during sheet formation, which together with the enzymatic CMNFs significantly enhanced the mechanical properties of both types of paper. The study found that refining before cationization favored the retention effect, primarily due to increased surface area and charge of the cationic CNFs, where remarkable increases in the breaking length of virgin (125.1%) and recycled paper (46.5%) were reached. The synergy between cationic CNFs and enzymatic CMNFs outperformed the use of commercial polyacrylamide, a non-biodegradable polyelectrolyte. This research highlights the potential of tailored CNFs in producing high-performance papers, while promoting sustainability and offering a plausible strategy to increase paper recycling rates. [ABSTRACT FROM AUTHOR]

The anionic nature of both cellulose fibres and reactive dyes prevents substantial exhaustion of dye from the dyebath, which is at neutral pH before alkali is added to initiate dye fixation. Conventionally, salt is added to minimize the electrostatic repulsions that interfere with dye sorption, but that increases salt loads in effluents. An alternative is to affix cationic agents on the cellulose to overcome the inherent anionic charge, but that has generally been observed to result in uneven dye sorption. The focus of investigations in this work is to examine the influence of the ratio of charges on cellulose (of affixed cationic charges to inherent anionic charges) on the extents and evenness of dye sorption. The cationisation agent 3-chloro-2-hydroxypropyl-N,N,N-trimethylammonium chloride (CHPTAC) was grafted on loose viscose fibres to yield 12 to 185 mmol kg−1 cationic group content on the fibre that exhibited an inherent carboxyl group content of 68 mmol kg−1. Three different dyes (of varying molecular sizes and anionic group content) were employed for examination of sorption profiles. The results from both zeta potential measurements and dye sorption profiles showed evidence of limited dye uptake until the cationic group content in fibres exceeded that of the inherent carboxyl groups. Thereafter, an uptick in dye sorption was observed, with dye sorption levels increasing with rise in degree of cationisation. There were differences between the dyes in their degrees of sorption, which appear correlated with their molecular sizes. [ABSTRACT FROM AUTHOR]

Antimicrobial and UV-blocking textiles (protective textiles) are quite required especially for outdoor workers and in hot weather countries. Herein, for the first time, under the effect of infrared radiation, the preparation of multi-finished viscose fabrics via the incorporation of metal organic framework-based on Cesium (Ce-MOF) is investigated. Ce-MOF using different ligands including 1,4-benzendicarboxylic acid (BDC), 1,2,4-benzene tricarboxylic acid (BDC-COOH) and 2-amino-1,4-dicarboxyic acid (BDC-NH2) were incorporated within viscose and cationic viscose (Q-viscose) fabrics in one-pot process. MOF uptake was significantly improved from 88.6 – 96.8 mg/g to 122.5 – 152.2 mg/g after the cationization process. Due to incorporation of Ce-MOF, viscose fabrics acquired creamy to yellowish color and became more thermally stable. Tensile strength was lowered by 8.9 – 17.4% for viscose and 17.1 – 20.3% for Q-viscose, after modification with Ce-MOFs. The estimated UV-protection factor (UPF) for Q-viscose fabrics was significantly increased to be 50.1– 88.1 after incorporation of Ce-BDC-COOH & Ce-BDC-NH2, achieving maximum UV protection. By comparing between Ce-BDC and Ce-BDC-COOH, the fabrics treated with Ce-BDC-NH2 showed the highest microbial protection against bacteria and fungus. After immobilization of Ce-MOF, the estimated inhibition zones were 11–14 mm & 15–18 mm against E. coli and 13–15 mm & 17–19 mm against C. albicans, for viscose and Q-viscose, respectively. [ABSTRACT FROM AUTHOR]

The cationic cellulose nanofibrils demonstrate outstanding properties and have garnered extensive attention as sustainable materials. However, the large-scale preparation of cationic cellulose nanofibrils was limited since the high crystallinity of plant fibers made them harder to disintegrate and nanofibrillate. In this study, cationic cellulose nanofibrils, HKCF, were produced from softwood bleached kraft pulp (SWBK) with 2,3-epoxypropyltrimethylammonium chloride (EPTAC) by disk milling, followed by high-pressure homogenization. Morphologies and structures of cationic fibers (KCF and CCF) and homogenized products were characterized. The influence of cationization combined with high mechanical shear on the degree of substitution (DS) of cationic fibers was studied. At the same molar ratios of EPTAC to anhydroglucose units and holding time, the DS of KCF was higher than that of CCF. Compared with simple mixing induced by conventional stirring, the high mechanical shear induced by disk milling could increase the cationic efficiency of EPTAC by at least 50%. After high-pressure homogenization, KCF was completely fibrillated to HKCF with nano-scaled dimensions. HKCF dispersion showed a Bingham flow behavior and viscosity-dominating fluid-like behavior. Our study provides a facile and effective industrialized approach for producing highly substituted cationic cellulose nanofibrils. [ABSTRACT FROM AUTHOR]

The study explores the application of tea leaf-extracted tannin as a bio-mordant and thyme extract as a natural dye on cationized silk-cotton blend fabric to enhance colour fastness and absorption. The colour strength and depth (shown as DL, Da, and Db values) on silk-cotton blend fabric were investigated in the CIE lab test. The results showed that temperature, shade percentage, and mordanting had a substantial impact on the dyeing process efficacy at DL = 30.61, Da = 11.49 and Db = 12.77. When the temperature was raised to 90 °C and the dye content was increased to 120%, the dyed sample's colour fastness (as measured by wash, rubbing, and perspiration) significantly improved, acquiring a grade of 4 to 5, which indicates good to excellent. There was a slight change in wet rubbing fastness from grade 3 to grade 4, indicating good to fair. The K/S values of the silk and cotton fibres, which ranged from 8.89 to 7.94 on average, respectively, demonstrated that the processes of bio-mordanting and cationization enhanced the absorption of dye. Tensile strength and extension increased in the weft direction to 22.19 N force and 5.21% extension at break, while the warp direction showed a fall to 6.63 N force and a rise in extension of 0.72%. FTIR spectroscopy confirmed the presence of Amino (N-H) bonds, Carbohydrate bonds (CH), Tannins, and Terpenoid phytochemicals of thyme in the dyed sample. The study highlights the potential of thyme extract as a natural dye and its benefits in improving the dyeing properties of silk-cotton blend fabric.

Single-molecule-based synergistic phototherapy holds great potential for antimicrobial treatment. Herein, we report an orthogonal molecular cationization strategy to improve the reactive oxygen species (ROS) and hyperthermia generation of heptamethine cyanine (Cy7) for photodynamic and photothermal treatments of bacterial infections. Cationic pyridine (Py) is introduced at the meso‑position of the asymmetric Cy7 with intramolecular charge transfer (ICT) to construct an atypical electron-transfer triad, which reduces ΔE S1-S0 , circumvents rapid charge recombination, and simultaneously enhances intersystem crossing (ISC) based on spin-orbit charge-transfer ISC (SOCT-ISC) mechanism. This unique molecular construction produces anti-Stokes luminescence (ASL) because the rotatable C N bond enriched in high vibrational-rotational energy levels improves hot-band absorption (HBA) efficiency. The obtained triad exhibits higher singlet oxygen quantum yield and photothermal conversion efficiency compared to indocyanine green (ICG) under irradiation above 800 nm. Cationization with Py enables the triad to target bacteria via intense electrostatic attractions, as well as biocidal property against a broad spectrum of bacteria in the dark. Moreover, the triad under irradiation can enhance biofilm eradication performance in vitro and statistically improve healing efficacy of MRSA-infected wound in mice. Thus, this work provides a simple but effective strategy to design small-molecule photosensitizers for synergistic phototherapy of bacterial infections. We developed an orthogonal molecular cationization strategy to enhance the reactive oxygen species and thermal effects of heptamethine cyanine (Cy7) for photodynamic and photothermal treatments of bacterial infections. Specifically, cationic pyridine (Py) was introduced at the meso ‑position of the asymmetric Cy7 to construct an atypical electron-transfer triad, which reduced ΔE S1-S0 , circumvented rapid charge recombination, and simultaneously enhanced intersystem crossing (ISC). This triad, with a rotatable C N bond, produced anti-Stokes luminescence due to hot-band absorption. The triad enhanced antimicrobial performance and statistically improved the healing efficacy of MRSA-infected wounds in mice. This site-specific cationization strategy may provide insights into the design of small molecule-based photosensitizers for synergistic phototherapy of bacterial infections. [Display omitted] [ABSTRACT FROM AUTHOR]

This research work investigates the chemical modification of cotton cellulose with a cationizing agent (CHPTAC, 3- chloro-2-hydroxylpropyl trimethyl ammonium chloride), which resulted in the enhanced dye uptake and increased color strength (K/S) on the dyed cotton fabric in the absence costly auxiliaries, such as sodium chloride and sodium hydroxide. The modified and unmodified cotton fabric samples were dyed using the exhaust dyeing method on a hightemperature dyeing machine with several reactive dyes of the Remazol class in different shade depths. The dyed samples were washed, dried and tested for K/S and colorfastness properties (washing, rubbing, and light), using standard test protocols. The results revealed that the color strength and the colorfastness properties of the modified dyed cotton fabric were significantly better than those of unmodified cotton. Thus, this study attempted a sustainable approach in cotton dyeing without using salt and alkali. [ABSTRACT FROM AUTHOR]

The study investigated the effect of modifying rapeseed husks with ammonia and epichlorohydrin on their sorption capacity against anionic reactive dyes: Reactive Black 5 (RB5) and Reactive Yellow 84 (RY84). Its scope included sorbents characterization (FTIR, pHPZC), determination of pH influence on the sorption effectiveness of dyes, the adsorption kinetics of dyes, as well as the maximum sorption capacity. The study proved that the reaction of rapeseed husk biomass with ammonia can lead to its amination, namely to the introduction of amine functional groups into the material's structure. The sorption effectiveness of RB5 and RY84 on the tested sorbents was the highest in the pH range of 2–3. The dye sorption kinetics was well described by the pseudo-second-order model. The sorption equilibrium time ranged from 90 to 180 min, and depended on the initial concentration of dyes and the number of amino groups on the sorbent's surface. The most efficient of the sorbents tested were rapeseed husks pre-activated with epichlorohydrin and then aminated with ammonia. Their sorption capacity determined for RB5 and RY84 was 135.83 mg/g and 114.23 mg/g, respectively, which was 794% and 737% higher than that of the non-modified husks. [ABSTRACT FROM AUTHOR]

The dyeing characteristics of hardwood kraft lignin (KL) were investigated on cotton fabrics, assessing its potential as a sustainable and environmentally friendly dye. Dyeability was evaluated by varying the KL concentrations, temperature, and time. An aqueous solution of Na2CO3 (1.0%) as the dye bath and a fabric-to-liquor ratio of 1:50 were used. Cationizing effects were studied using (3-chloro-2-hydroxypropyl) trimethylammonium chloride (CHPTAC), and the mordanting effects of various mordants were also evaluated. Post-mordanting was performed with FeSO4, FeCl2, Fe-lactate (Fe-lac), MgSO4, CuCl2, CuSO4, and Al2(SO4)3. A mordant concentration of 1 mM o.w.f. (0.5 mM for Al2(SO4)3), with a liquor ratio of 1:30, at 60 °C for 30 min were employed. Suitable dyeing conditions were 2.0% o.w.b., 90 °C, and 90 min, resulting in a brownish color of the cotton fabric. The fabrics exhibited a range of light brown to light grayish brown colors and showed lighter colors than the untreated fabrics when mordanted with MgSO4 and Al2(SO4)3. The color difference (ΔE) between cationized and uncationized cotton fabrics was 3.48. From the colorfastness assessment, KL-dyed cotton fabric showed good rubbing and washing fastness for staining, but poor light and washing fastness for fading.

The dyeing characteristics of hardwood kraft lignin (KL) were investigated on cotton fabrics, assessing its potential as a sustainable and environmentally friendly dye. Dyeability was evaluated by varying the KL concentrations, temperature, and time. An aqueous solution of Na2CO3 (1.0%) as the dye bath and a fabric-to-liquor ratio of 1:50 were used. Cationizing effects were studied using (3-chloro-2-hydroxypropyl) trimethylammonium chloride (CHPTAC), and the mordanting effects of various mordants were also evaluated. Post-mordanting was performed with FeSO4, FeCl2, Fe-lactate (Fe-lac), MgSO4, CuCl2, CuSO4, and Al2(SO4)3. A mordant concentration of 1 mM o.w.f. (0.5 mM for Al2(SO4)3), with a liquor ratio of 1:30, at 60 °C for 30 min were employed. Suitable dyeing conditions were 2.0% o.w.b., 90 °C, and 90 min, resulting in a brownish color of the cotton fabric. The fabrics exhibited a range of light brown to light grayish brown colors and showed lighter colors than the untreated fabrics when mordanted with MgSO4 and Al2(SO4)3. The color difference (E) between cationized and uncationized cotton fabrics was 3.48. From the colorfastness assessment, KL-dyed cotton fabric showed good rubbing and washing fastness for staining, but poor light and washing fastness for fading. [ABSTRACT FROM AUTHOR]

Biomass-based surfactants have excellent surface activities, showing the common characteristics of natural biomass including biocompatibility, biodegradability and non-toxicity, which are environmental-friendly and accord with the green development direction. In this study, a keratin based quaternary ammonium salt surfactant (denoted as E-K) was prepared by cationic modification of keratin with epoxypropyldodecyldimethylammonium chloride (EPDDMAC). The characterization of E-K by FTIR and the conversion rate of -NH2 in keratin confirmed the successful preparation of E-K. Subsequently, surface activity such as surface tension (γcmc) and critical micelle concentration (cmc), physicochemical properties such as HLB value, isoelectric point, foaming property and emulsifying property, as well as antibacterial activity and biodegradability were investigated. The results show that E-K possesses good surface activity, acceptable emulsifying and foaming ability. The HLB of E-K is 14-15, and it has excellent compatibility with commercial surfactants commonly used in hair care products. Particularly, E-K is a betaine zwitterionic surfactant, and its isoelectric point increases from 3.8 to 9.2 due to cationization. This means that the quaternized keratin hydrolysate is easily adsorbed on the hair surface, and makes the hair surface smoother and denser, which was proved by the adsorption test and SEM observation. Furthermore, E-K has outstanding antibacterial activity against E. coli and S. aureus, and the BOD5/CODCr value indicated that it is easily biodegradable. Therefore, the prepared biomass-based surfactant (E-K) has great potential application in hair care products and other products related to antibacterial and biodegradable surfactants. [ABSTRACT FROM AUTHOR]

In this work different types of nanocomposites have been synthesized in a facile approach, where the major components of the target material are unsaturated polyester resin, sawdust of Swietenia mahagoni and copper nanoparticles. To develop the desired nanocomposites initially, nanosol of copper particles has been synthesized in our laboratory thereafter the copper nanoparticles (in the sol) are impregnated on/into the Swietenia mahagoni sawdust to make it strong and durable. The impregnated copper nanoparticle is functioning to improving the mechanical properties and controlling of biodegradability. Such strong and durable sawdust is a novel reinforcing agent for the target unsaturated polyester resin nanocomposite. The impregnated copper nanoparticles also foster the antifungal activity (~ 14%), crystallinity (~ 5.6%), durability (~ 10%), and mechanical strength (~ 56%) of the nanocomposites compare with the untreated sawdust-based composites. Cationization of sawdust has been done as the nanoparticles have been stabilized in polyvinyl alcohol medium which makes a negative surface of the nanoparticles resulting to repulsed by the non-cationized sawdust surface. The physicochemical, morphological, mechanical, thermal properties along with the biodegradability of the developed nanocomposites have been evaluated and the possible correlations have also been explained with straightforward approaches. The reinforcement performances for untreated sawdust composite, cationized sawdust composite, and copper impregnated sawdust nanocomposite increase ~ 30%, 91%, and 104%, respectively. Composite properties were investigated systematically by using Fourier transform infrared spectroscopy, field emission scanning electron microscopy, thermogravimetric analysis, differential scanning calorimetry, X-ray diffraction, etc. The water uptake capacity of the developed composites has been followed by a typical Fickian diffusion behaviour. Throughout this work, the obtained nanocomposites may be a good alternative to wood especially for automobile, aeroplane, train and furniture industry as well as indoor to outdoor heavy-duty applications. [ABSTRACT FROM AUTHOR]

Pectin cellulose grafted with glycidyltrimethylammoniochloride (GTMAC) was successfully obtained following the processes of depectinfibrillation and cellulose cationization using ordinary Shatian pomelo peel produced in Yongzhou, Hunan, as the raw material. This is the first report on a new type of functionalized sodium alginate-immobilized material prepared from the fibers of pomelo peel. The material was prepared by combining modified pomelo peel cellulose and sodium alginate following the processes of physical and chemical double cross-linking. The prepared material was used to embed the target bacteria to achieve the biodegradation of p-aniline. The concentration of CaCl2 was adjusted when the alginate gelled, and the alginate to yuzu peel cellulose ratio was tuned. The immobilized material-embedded bacteria help achieve the best degradation effect. Bacteria are embedded during the process of the degradation of aniline wastewater, and the functionalization of the cellulose/sodium alginate-immobilized material results in unique surface structure performance. The performance of the prepared system is better than that of the single sodium alginate-based material characterized by a large surface area and good mechanical properties. The degradation efficiency of the system is improved significantly for the cellulose materials, and the prepared materials can potentially find applications in the field of bacteria-fixed technology. HIGHLIGHTS Pomelo peel fiber was extracted for the first time and used in the preparation of immobilized material.; By combining with sodium alginate, the specific surface area of the fixed material can be increased by the pomelo peel fiber with a spiral tube shape and rough surface.; The cationic-modified pomelo peel fiber can improve the mechanical properties and stability of the immobilized material by ionic bonding.;

The textile industry has been exploring sustainable chemicals and natural alternatives to replace harmful and carcinogenic substances used in different stages of textile production for dyeing textiles. Natural dyes are gaining popularity, as they are environmentally friendly and less harmful. Betacyanin, a type of pigment obtained from red pitahaya, commonly known as red dragon fruit (Hylocereus polyrhizus), has peels that are available as agricultural waste and can be used to meet the demand for natural dye production. This study aimed to explore and utilize dragon fruit’s peel as a natural colorant for dyeing 100% cotton knit fabric (scoured and bleached single jersey plain knit) of 170 g/m2, which could transform a low-value material into a valuable product. However, cotton’s phenolic nature and oxidation process result in negative charges on its surface, making natural dyeing challenging. Cationization with cationic agents (ForCat NCH, a mixture of cationic polyamine and 1,3,dichlori-2-propanol) and mordanting (potassium alum or potassium aluminum sulfate) were carried to improve dye exhaustion and enhance colorfastness properties. Spectrophotometer 800 was used to measure color strength (K/S), and several fastness tests, including wash, perspiration, and rubbing were conducted to assess the final product’s performance. The process parameters, such as temperatures, times, pH levels, and dye concentrations were varied to understand better the optimum conditions.

The study investigated the effect of modifying rapeseed husks with ammonia and epichlorohydrin on their sorption capacity against anionic reactive dyes: Reactive Black 5 (RB5) and Reactive Yellow 84 (RY84). Its scope included sorbents characterization (FTIR, pHPZC), determination of pH influence on the sorption effectiveness of dyes, the adsorption kinetics of dyes, as well as the maximum sorption capacity. The study proved that the reaction of rapeseed husk biomass with ammonia can lead to its amination, namely to the introduction of amine functional groups into the material’s structure. The sorption effectiveness of RB5 and RY84 on the tested sorbents was the highest in the pH range of 2–3. The dye sorption kinetics was well described by the pseudo-second-order model. The sorption equilibrium time ranged from 90 to 180 min, and depended on the initial concentration of dyes and the number of amino groups on the sorbent’s surface. The most efficient of the sorbents tested were rapeseed husks pre-activated with epichlorohydrin and then aminated with ammonia. Their sorption capacity determined for RB5 and RY84 was 135.83 mg/g and 114.23 mg/g, respectively, which was 794% and 737% higher than that of the non-modified husks.

Cellulose is the most abundant renewable polymer on Earth and can be obtained from several different sources, such as trees, grass, or biomass residues. However, one of the issues is that not all the fractionation processes are eco-friendly and are essentially based on cooking the lignocellulose feedstock in a harsh chemical mixture, such as NaOH + Na2S, and water, to break loose fibers. In the last few years, new sustainable fractionation processes have been developed that enable the obtaining of cellulose fibers in a more eco-friendly way. As a raw material, cellulose's use is widely known and established in many areas. Additionally, its products/derivatives are recognized to have a far better environmental impact than fossil-based materials. Examples are textiles and packaging, where forest-based fibers may contribute to renewable and biodegradable substitutes for common synthetic materials and plastics. In this review, some of the main structural characteristics and properties of cellulose, recent green extraction methods/strategies, chemical modification, and applications of cellulose derivatives are discussed. [ABSTRACT FROM AUTHOR]

Crop wastes are renewable and abundant lignocellulosic resource, while their effective utilization is limited due to the recalcitrance of plant cell wall. In this study, by using a facile mechanochemical method, reed straw fiber was simultaneously cationized and defibrillated to obtain cationic lignocellulose nanofibers (LCNFs) without organic solvent. The obtained cationic LCNFs were 2–4 nm wide and several micrometers long with excellent re-dispersibility in water arising from the high zeta potential of + 40 mV. As a paper-reinforcement agent, cationic LCNFs could give coated paper good oil resistance with the maximum Kit rating of 12/12. Meanwhile, the mechanical properties of the coated paper were also remarkably enhanced with the tensile strength and Young's modulus increased by 144% and 124%, respectively. They also gave the paper antibacterial properties because of the presence of quaternary ammonium groups. Overall, this study provides an efficient utilization option for crop wastes as well as a value-added lignocellulosic product. [ABSTRACT FROM AUTHOR]

In the scope of the study, it was aimed to examine the usability of cationization process instead of bleaching process in the pretreatment process of terry fabrics and the effect of these process parameters on fabric performance properties on tensile strength, softness and hydrophility values. For this purpose, 4 different towel fabrics with two different weights and two different pile raw materials (100% cotton and 100% modal) and all other characteristics are same, were produced. Then, sample fabrics were subjected to the cationization process at different concentrations after the bleaching process, while some of them were unbleached. After all the processes applied, the processed samples were tested in accordance with the standards. As a result, it was determined that applying cationization process instead of bleaching process contributed positively to terry fabrics in terms of tensile strength and softness, and acceptable results were obtained in terms of hydrophility. [ABSTRACT FROM AUTHOR]

The textile industry has been exploring sustainable chemicals and natural alternatives to replace harmful and carcinogenic substances used in different stages of textile production for dyeing textiles. Natural dyes are gaining popularity, as they are environmentally friendly and less harmful. Betacyanin, a type of pigment obtained from red pitahaya, commonly known as red dragon fruit (Hylocereus polyrhizus), has peels that are available as agricultural waste and can be used to meet the demand for natural dye production. This study aimed to explore and utilize dragon fruit's peel as a natural colorant for dyeing 100% cotton knit fabric (scoured and bleached single jersey plain knit) of 170 g/m2, which could transform a low-value material into a valuable product. However, cotton's phenolic nature and oxidation process result in negative charges on its surface, making natural dyeing challenging. Cationization with cationic agents (ForCat NCH, a mixture of cationic polyamine and 1,3,dichlori-2-propanol) and mordanting (potassium alum or potassium aluminum sulfate) were carried to improve dye exhaustion and enhance colorfastness properties. Spectrophotometer 800 was used to measure color strength (K/S), and several fastness tests, including wash, perspiration, and rubbing were conducted to assess the final product's performance. The process parameters, such as temperatures, times, pH levels, and dye concentrations were varied to understand better the optimum conditions. [ABSTRACT FROM AUTHOR]

Cotton cationization with low molecular weight or polymeric cationic modifiers allows the effective dyeing of cotton substrates with reactive dyes under salt-free and more environmentally friendly conditions. The current work focuses on the spectroscopic study of the intermolecular interactions, which dictate the physicochemical process associated with fabric dyeing. Water-soluble cationic copolymers of vinyl benzyl chloride (VBC) and vinyl benzyl triethylammonium chloride (VBCTEAM) have been used as cellulose cationic modifiers. Dye uptake was assessed using Remazol Brilliant Blue R and Novacron Ruby S-3B dyes. The study involves ATR-FTIR, UV-Vis, fluorescence, and XPS spectroscopy. The results of binary polymer-rich dye-polymer aqueous solutions or dye-polymer precipitates at stoichiometric charge-ratio revealed that the sulfonate/sulfate anions of the dyes interact with the cationic VBCTEAM units of the polymer via electrostatic interactions. Moreover, the comparative study of dye application on modified and unmodified fabrics suggests that, unlike the latter, where dyes are chemically bound to cellulose, electrostatic forces dominate the interaction of modified fabrics with dye molecules. [ABSTRACT FROM AUTHOR]

Cotton fabric was chemically modified with gelatin, extracted from fleshing waste of collagen by thermal hydrolysis process to increase the dyeing capability of reactive dye. Gelatin imparts new functional groups with fabric and develops Ammonia ion in slightly acid conditions to obtain cationized cotton fabric permit salt and alkali-free reactive dyeing with acceptable shade depth. The imparting of gelatin on the cotton fabric was confirmed by FTIR, UV/VIS absorption, and K/S values. The result shows that they have advantage of high dye utilization and better fastness. Color fastness of treated dyed fabric was equal to the untreated dyed fabric and obtained 4/5 washing fastness, 5 rubbing fastnesses, and 4/5 perspiration fastness. The UV/VIS absorption results show 6.4% improvement in exhaustion and K/S results have 7% improvement in fixation and 9.4% in dye utilization to that of untreated dyeing with salt. Cationized fabric not only increased the exhaustion of the dye but also improved the crease resistance angle at 120° due to the formation of cross-linkage between amide group and the carboxylic acid. To obtain the expected results, cationization was done at alkaline media and the optimum parameter was determined, whereas dyeing conducted at slightly acidic media with optimum parameters.

Digital printing has the potential of enabling cleaner printing or even dyeing of cotton fabrics. However, whilst effluent-free digital printing and dyeing of synthetic textile fabrics have seen some success, the same remain elusive for cotton fabrics. The study reported in this paper aimed to optimize the process parameters of cationic pre-treatment with a view to creating a cleaner cotton fabric digital printing process that could be sustainably implemented at bulk-scale production. Thus, process variables were screened using the one-factor-at-a-time approach to select optimum experimental regions. A Box–Behnken design was used to investigate the combined effect of selected factors namely amount of thickener (150–200 g/L), urea (75–125 g/L) and alkali (10–20 g/L) on the color strength, dye fixation and ink penetration of cationized and digital-printed cotton fabrics. The significant models showed excellent fitting of the data. The optimum levels of the factors, namely, amount of thickener, urea and alkali were found 200 g/L, 125 g/L and 10 g/L, respectively. The bulk-scale experiments carried out at optimum levels have shown that an average of ca. 52% of reactive ink, 37.5% of urea and 50% of alkali can be saved by digital printing of cationized cotton along with generation of nearly colorless effluent.

Reaktif boyarmaddeler pamuğun boyanmasında en yaygın kullanılan boyarmaddelerdir. Pamuklu kumaşların reaktif boyanması için yüksek miktarda kullanılan elektrolit kaçınılmaz olarak çevresel tehditler oluşturmaktadır. Kitosan üstün özelliklerinden dolayı tekstilde birçok alanda farklı amaçlarla kullanılmaktadır. Bu çalışmada, sentetik polielektrolit poli(akrilik asidin sodyum tuzu) reaktif boyamada inorganik elektrolit sodyum klorür yerine kullanımı ve kitosanın kumaşın reaktif boyama davranışı üzerindeki etkileri araştırılmıştır. Ayrıca kumaşların yıkama haslıkları ve ultraviyole koruma faktörleri de gözlemlenmiştir. Boyamadan önce kitosan ile muamele ve boyamada sodyum klorür kullanımı konvansiyonel boyamalara göre renk derinliklerini arttırmış ve bu artış kitosan konsantrasyonundaki artışla devam etmiştir. Öyle ki, %8 konsantrasyonda kitosan uygulamasını takiben %2 konsantrasyonda yapılan boyamadan, %3 konvansiyonel boyamanın renk kuvvetine benzer değerler elde edilmiştir. Sodyum klorür konsantrasyon artışının renk derinliği üzerindeki etkisi polielektrolitten daha belirgin olarak gözlemlenmiştir. Poli (akrilik asidin sodyum tuzunun) pamuğun reaktif boyamasındaki çalışma prensibinin iyonlaşamaması, sıcaklık-konsantrasyon-pH duyarlılığı ve hidrofobik boya kombinasyonları oluşturması nedeniyle nispeten karmaşık olduğu anlaşılmıştır. Ayrıca boyarmaddelerin farklı tuz duyarlılıklarının da elektrolitlerin etkisinde farklılık yaratmış olabileceği düşünülmüştür. Kitosan aplike edilen ve boyanan numunelerin yıkama haslıkları iyi-mükemmel seviyede iken, kitosan aplikasyonunda kullanılan çapraz bağlayıcının bu değerleri 0,5 puan kadar artırdığı görülmüştür. Boyarmaddelerin ultraviyole koruma faktörünü arttırmada kitosandan daha etkili olduğu gözlemlenmiştir.

The dyeing of cotton with synthetic dyes is associated with environmental and health problems, which can be overcome using natural dyes. But in natural dyeing, metal mordants are commonly used, which are also related to harmful effects on the environment and health. That is why the green process should be investigated. In this work, cotton was cationized with proteins from various sources to improve its dyeing with cochineal natural dye. Different techniques for fixing proteins in cotton were evaluated, such as direct cationization in the fabric, fixation by cross-linking, and the oxidation of cotton. All proteins evaluated and their fixation techniques resulted in greater dye adsorption than cotton without cationization. The oxidation of cotton before the application of the protein was the technique that most increased the dye adsorption in all evaluated proteins. However, the fixation of ovalbumin, keratin, and collagen proteins by cross-linking showed higher color strength after the washing process. In view of all the comparisons made, the pretreatment by fixing ovalbumin with cross-linking agent resulted in the higher values of adsorption and color strength, besides a good color uniformity. Thus, ovalbumin is a viable and eco-friendly alternative in the dyeing of cotton with cochineal.

This paper aims to assess the potential for the use of waste cellulosic fibers and recycled grains as materials for the development of abrasives. However, abrasive wear produces low durability and a lot of waste. The improvement of adhesion between the components of composites is the key to extending their lifetime. For this purpose, the surface of the fiber was modified by cationic reactive agents. Composites were manufactured with treated fibers, polyurethane matrix, and iron shavings as abrasive grains. To obtain this product, the coating phenomenon is maintained. DSC and TGA analysis show the thermal stability of abrasives. Contact angle and zeta potential measurements have been used to evaluate the specific surface-chemical changes imparted by surface treatments of specimens. EDX and SEM observations indicate that matrix-reinforcing particle-phase boundaries have a very important effect on the using properties of these materials and revealed that the abrasion resistance of composite is sensitive to fiber/matrix adhesion.

Vinpocetine (VNP), a semisynthetic active pharmaceutical ingredient, is used for oral management of cerebrovascular diseases because of its ability to enhance the blood flow to the brain. However, despite that, the therapeutic application of VNP is restricted due to its reduced bioavailability and diminished brain levels that could be attributed to its low aqueous solubility, short half-life, and presystemic metabolism exposure. Accordingly, the goal of this work was to explore the ability of surface-tailored intranasal emulsomes to boost brain delivery of the drug. A 3221 factorial design was implemented to explore the impact of phospholipid (PL) to solid lipid weight ratio, PL to cholesterol molar ratio, and type of solid lipid on vesicle size, zeta potential, drug entrapment, and release efficiency of the new developed VNP emulsomes. Tailoring of the optimized emulsomal surface formulation was performed using either cationization or PEGylation approaches to boost blood–brain barrier penetration. The pharmacokinetic assessment in rats showed significantly improved bioavailability of VNP emulsomal formulations compared to the oral market product. Additionally, surface-tailored emulsomes exhibited significantly higher brain levels compared to the optimized emulsomes. Based on these findings, the proposed surface-tailored emulsomes could be considered as a promising platform for achieving high brain levels of VNP following intranasal administration.

This work describes the cationization and carboxymethylation of agave fructans and their physicochemical and functional characterization. The results show that the modification gives rise to degrees of substitution of 0.487 and 0.133 for the carboxymethylated and cationic derivatives, respectively. FTIR, DSC and HPLC-SEC results demonstrated the incorporation of quaternary ammonium and carboxymethyl groups in the native fructan molecular structure. As a result of the structure modification, the increase in molecular weight, the appearance of new bands in the FTIR spectrum and changes in thermal properties were observed. The zeta potential demonstrated the anionic and cationic character of the modified fructans. There were no changes in the swelling capacity, however the cationic fructans have a higher oil holding capacity. Native and modified fructans exhibited antimicrobial effect against Staphylococcus aureus, Listeria monocytogenes, Escherichia coli, and Salmonella enterica Typhimurium with higher antimicrobial activity against Gram negative microorganisms.

Textile substrates incorporated with antimicrobial agents offer a great advantage in treating chronic wounds infected with microbes. In this work, a simple one-step process is proposed to develop cellulosic nonwoven incorporated with silver nanoparticles using wet laying technique. In order to improve the dispersion of the fibers during wet laying and better binding of silver nanoparticles, the fibers were cationized using CHPTAC. The decrease in absorbance value of the drain at 470 nm confirms binding of nanosilver to the fiber. A maximum zone of inhibition of 18 mm and 19 mm was obtained for cationized web. The developed web can be used for wound dressing applications.

Textile substrates incorporated with antimicrobial agents offer a great advantage in treating chronic wounds infected with microbes. In this work, a simple one-step process is proposed to develop cellulosic nonwoven incorporated with silver nanoparticles using wet laying technique. In order to improve the dispersion of the fibers during wet laying and better binding of silver nanoparticles, the fibers were cationized using CHPTAC. The decrease in absorbance value of the drain at 470 nm confirms binding of nanosilver to the fiber. A maximum zone of inhibition of 18 mm and 19 mm was obtained for cationized web. The developed web can be used for wound dressing applications. [ABSTRACT FROM AUTHOR]

The biodegradable and non-toxic Bioflocculants have attracted considerable interest as alternative to non-biodegradable chemical flocculants. However, the cost of fermentation media for bioflocculant production and low flocculation efficiency is a major challenge. In this study, we grow Bacillus spp isolated from sediment of local clay pot on spoilt orange juice to produce bioflocculant. The culture supernatant of the bacilli grown on spoilt orange juice were screen for bioflocculant production using Jar test method and Kaolin clay suspension as model wastewater. The effect of pH and temperature on the bioflocculant production were also studied. The effect of cations on bioflocculation rate of the bioflocculant produced were tested via hybridization of the bioflocculant with the cations. The bioflocculation efficiency of the bioflocculant on sample wastewaters were also determined. The bacilli isolated initially had flocculation rate between 31.1±1.6 % to 76.4±1.2% when cultured on screening media. Bioflocculation rate peaked to 77.9% at 40 oC while the lowest flocculation rate (55.41%) was obtained at 25 oC. The optimum bioflocculant production (about 78%) was recorded at pH 6 - 7 while the highest bioflocculant production (84.2%) was achieved at 96th hour of incubation. Na+ and Fe3+ had serious inhibitory effect on the bioflocculant while K+, Ca2+, Mg2+ and Al3+ had less or no effect on the bioflocculant. The bioflocculant had up to 77.7% and 64.5 % on Kitchen wastewater and aquaculture wastewater. This study reveals the potential for utilization of spoilt orange juice as fermentable substrate for bioflocculant production especially if the fermentation conditions and flocculation parameters are well optimized. [ABSTRACT FROM AUTHOR]

Cotton fabric was chemically modified with gelatin, extracted from fleshing waste of collagen by thermal hydrolysis process to increase the dyeing capability of reactive dye. Gelatin imparts new functional groups with fabric and develops Ammonia ion in slightly acid conditions to obtain cationized cotton fabric permit salt and alkali-free reactive dyeing with acceptable shade depth. The imparting of gelatin on the cotton fabric was confirmed by FTIR, UV/VIS absorption, and K/S values. The result shows that they have advantage of high dye utilization and better fastness. Color fastness of treated dyed fabric was equal to the untreated dyed fabric and obtained 4/5 washing fastness, 5 rubbing fastnesses, and 4/5 perspiration fastness. The UV/VIS absorption results show 6.4% improvement in exhaustion and K/S results have 7% improvement in fixation and 9.4% in dye utilization to that of untreated dyeing with salt. Cationized fabric not only increased the exhaustion of the dye but also improved the crease resistance angle at 120° due to the formation of cross-linkage between amide group and the carboxylic acid. To obtain the expected results, cationization was done at alkaline media and the optimum parameter was determined, whereas dyeing conducted at slightly acidic media with optimum parameters. [ABSTRACT FROM AUTHOR]

Majority of knit goods processed are dyed with reactive dyes. Cationization of cotton knits is one of the effective ways to dye cotton fabric without salt using reactive dye. The effective reuse of cationized bath was done with topping of CHPTAC and a topping of 15gpl led to matching of shade to that of control fabric. FT-IR and SEM characterization confirms the surface modification and Fastness tests have been performed for the stripping studies. No significant color difference is observed in terms of K/S, L* a* and b* values of stripped and redyed fabrics. [ABSTRACT FROM AUTHOR]

This paper aims to assess the potential for the use of waste cellulosic fibers and recycled grains as materials for the development of abrasives. However, abrasive wear produces low durability and a lot of waste. The improvement of adhesion between the components of composites is the key to extending their lifetime. For this purpose, the surface of the fiber was modified by cationic reactive agents. Composites were manufactured with treated fibers, polyurethane matrix, and iron shavings as abrasive grains. To obtain this product, the coating phenomenon is maintained. DSC and TGA analysis show the thermal stability of abrasives. Contact angle and zeta potential measurements have been used to evaluate the specific surface-chemical changes imparted by surface treatments of specimens. EDX and SEM observations indicate that matrix-reinforcing particle-phase boundaries have a very important effect on the using properties of these materials and revealed that the abrasion resistance of composite is sensitive to fiber/matrix adhesion. [ABSTRACT FROM AUTHOR]

Digital printing has the potential of enabling cleaner printing or even dyeing of cotton fabrics. However, whilst effluent-free digital printing and dyeing of synthetic textile fabrics have seen some success, the same remain elusive for cotton fabrics. The study reported in this paper aimed to optimize the process parameters of cationic pre-treatment with a view to creating a cleaner cotton fabric digital printing process that could be sustainably implemented at bulk-scale production. Thus, process variables were screened using the one-factor-at-a-time approach to select optimum experimental regions. A Box–Behnken design was used to investigate the combined effect of selected factors namely amount of thickener (150–200 g/L), urea (75–125 g/L) and alkali (10–20 g/L) on the color strength, dye fixation and ink penetration of cationized and digital-printed cotton fabrics. The significant models showed excellent fitting of the data. The optimum levels of the factors, namely, amount of thickener, urea and alkali were found 200 g/L, 125 g/L and 10 g/L, respectively. The bulk-scale experiments carried out at optimum levels have shown that an average of ca. 52% of reactive ink, 37.5% of urea and 50% of alkali can be saved by digital printing of cationized cotton along with generation of nearly colorless effluent. [ABSTRACT FROM AUTHOR]

Cationization of cotton is considered to be an effective way to realize salt-free dyeing of reactive dyes. However, applying cotton modified with glycidyltrimethylammonium chloride (GTA) suffers from large consumption of the cationic reagent. One of the reasons is that high crystallinity of cotton fibers hinders the penetration of the reagents into the cellulose interior and limits the reaction between them. This paper designed to use alcohol-water-NaOH system to pretreat the fibers before cationization. With this method, crystallinity of the cotton fibers is decreased and more reactive –OH is exposed, resulting in much higher fiber-reagent reactivity and increased GTA utilization. Influence of alcohol type, alcohol-to-water ratio, and quantity of NaOH on fiber crystallinity and GTA dosage for cationization are all examined. It is found that for achieving 96.0% fixation of C.I. Reactive Black 5 in the absence of salt, GTA dosage can be reduced by half when the fibers are pretreated by alcohol-water-NaOH. Compared with ethanol, n-propanol and isopropanol, tert-butyl alcohol incorporated system shows better performance in increasing fiber reactivity due to their weaker ability to dissolve ions. In this study, XRD and FT-IR are used to demonstrate changes in crystallinity of the fibers after pretreatment. The alteration in micromorphology and hydrophilicity of the pretreated fibers is observed by SEM and water contact angle test, respectively. Furthermore, the alcohol-water-NaOH system can be recycled to show very good repeatability. Notably, all dyed samples pretreated with the system present high color saturation and satisfactory color fastness, especially that the wet rub fastness reaches 4–5 grade, which is one grade higher than that obtained from the conventional dyeing with salt. The above findings prove that alcohol-water-NaOH pretreatment is effective in enhancing reactivity of the cotton fibers and penetrability of the agent, and it shows promising prospects in real application. [ABSTRACT FROM AUTHOR]

Vinpocetine (VNP), a semisynthetic active pharmaceutical ingredient, is used for oral management of cerebrovascular diseases because of its ability to enhance the blood flow to the brain. However, despite that, the therapeutic application of VNP is restricted due to its reduced bioavailability and diminished brain levels that could be attributed to its low aqueous solubility, short half-life, and presystemic metabolism exposure. Accordingly, the goal of this work was to explore the ability of surface-tailored intranasal emulsomes to boost brain delivery of the drug. A 3221 factorial design was implemented to explore the impact of phospholipid (PL) to solid lipid weight ratio, PL to cholesterol molar ratio, and type of solid lipid on vesicle size, zeta potential, drug entrapment, and release efficiency of the new developed VNP emulsomes. Tailoring of the optimized emulsomal surface formulation was performed using either cationization or PEGylation approaches to boost blood-brain barrier penetration. The pharmacokinetic assessment in rats showed significantly improved bioavailability of VNP emulsomal formulations compared to the oral market product. Additionally, surface-tailored emulsomes exhibited significantly higher brain levels compared to the optimized emulsomes. Based on these findings, the proposed surface-tailored emulsomes could be considered as a promising platform for achieving high brain levels of VNP following intranasal administration. [ABSTRACT FROM AUTHOR]

The dyeing of cotton with synthetic dyes is associated with environmental and health problems, which can be overcome using natural dyes. But in natural dyeing, metal mordants are commonly used, which are also related to harmful effects on the environment and health. That is why the green process should be investigated. In this work, cotton was cationized with proteins from various sources to improve its dyeing with cochineal natural dye. Different techniques for fixing proteins in cotton were evaluated, such as direct cationization in the fabric, fixation by cross-linking, and the oxidation of cotton. All proteins evaluated and their fixation techniques resulted in greater dye adsorption than cotton without cationization. The oxidation of cotton before the application of the protein was the technique that most increased the dye adsorption in all evaluated proteins. However, the fixation of ovalbumin, keratin, and collagen proteins by cross-linking showed higher color strength after the washing process. In view of all the comparisons made, the pretreatment by fixing ovalbumin with cross-linking agent resulted in the higher values of adsorption and color strength, besides a good color uniformity. Thus, ovalbumin is a viable and eco-friendly alternative in the dyeing of cotton with cochineal. [ABSTRACT FROM AUTHOR]

The biodegradable and non-toxic Bioflocculants have attracted considerable interest as alternative to non-biodegradable chemical flocculants. However, the cost of fermentation media for bioflocculant production and low flocculation efficiency is a major challenge. In this study, we grow Bacillus spp isolated from sediment of local clay pot on spoilt orange juice to produce bioflocculant. The culture supernatant of the bacilli grown on spoilt orange juice were screen for bioflocculant production using Jar test method and Kaolin clay suspension as model wastewater. The effect of pH and temperature on the bioflocculant production were also studied. The effect of cations on bioflocculation rate of the bioflocculant produced were tested via hybridization of the bioflocculant with the cations. The bioflocculation efficiency of the bioflocculant on sample wastewaters were also determined. The bacilli isolated initially had flocculation rate between 31.1±1.6 % to 76.4±1.2% when cultured on screening media. Bioflocculation rate peaked to 77.9% at 40 oC while the lowest flocculation rate (55.41%) was obtained at 25 oC. The optimum bioflocculant production (about 78%) was recorded at pH 6 – 7 while the highest bioflocculant production (84.2%) was achieved at 96th hour of incubation. Na+ and Fe3+ had serious inhibitory effect on the bioflocculant while K+, Ca2+, Mg2+ and Al3+ had less or no effect on the bioflocculant. The bioflocculant had up to 77.7% and 64.5 % on Kitchen wastewater and aquaculture wastewater. This study reveals the potential for utilization of spoilt orange juice as fermentable substrate for bioflocculant production especially if the fermentation conditions and flocculation parameters are well optimized.

In this work, we aimed to tune cellulose nanocrystals (CNCs) properties by introducing different functional groups (aldehyde, carboxyl, silane, and ammonium groups) on the surface through different chemical modifications. These functional groups were obtained by combining: the periodate oxidation with TEMPO-oxidation, aminosylation or cationization. CNCs produced and their films were characterized to elucidate their performances. The results showed that the properties of obtained CNCs varied depending on the grafted functionalities on the surface. The results reveal that after each modification a colloidal stability is preserved. Interestingly, Periodate oxidation of cellulose nanocrystals results in film components that interact through intra- and intermolecular hemiacetals and lead to films with a tensile strength of 116 MPa compared to the pristine CNCs, in contrast the subsequent modifications led to lower tensile strength. Of note, remarkable thermal stability has been achieved after modifications reaching a maximum of 280 °C. The oxygen barrier properties of the films after modifications varied between 0.48 and 0.54 cm3μm/(m2d*kPa) at 50 % RH. • The films produced from different modified CNCs showed better thermal stability compared to the pristine CNC films. • The combination of periodate oxidation and EPTMAC cationization resulted in lower E-modulus and higher strain at break. • All the modification treatments can preserve the crystalline structure of the CNCs. [ABSTRACT FROM AUTHOR]

Abstract Development of cationic flocculants from lignocellulosic wastes not only eliminates the health and environmental concerns associated with the use of conventional chemicals, but also is the way of waste valorization. In the present study, cellulose fibers extracted from rice husk were cationized through an optimization method based on response surface methodology. The fibers cationized at the optimal conditions had a zeta-potential of 15.2 ± 1.0 mV, while the highest potential was + 8.76 mV, for the samples developed before optimization. FTIR analysis proved the presence of the corresponding functional groups. The functionalized fibers were biodegradable and had absolutely positive surface charges at a broad pH range. The cationized fibers were employed as a flocculant to remove turbidity from the synthetic wastewaters at various pHs and initial turbidities. The cationic fibers showed the excellent turbidity removals up to 98.5% from the synthetic wastewater without the need for conventional coagulants. In contrast to traditionally cationized fibers, the synthesized flocculants did not affect the effluent color during coagulation–flocculation. The charge neutralization and bridging through adsorption were the governing mechanisms of flocculation. The procedure can be applied on lignocellulosic wastes to develop cationic fibers with the excellent flocculation ability and suitable operational characteristics.

Cellulose is the most abundant renewable polymer on Earth and can be obtained from several different sources, such as trees, grass, or biomass residues. However, one of the issues is that not all the fractionation processes are eco-friendly and are essentially based on cooking the lignocellulose feedstock in a harsh chemical mixture, such as NaOH + Na2S, and water, to break loose fibers. In the last few years, new sustainable fractionation processes have been developed that enable the obtaining of cellulose fibers in a more eco-friendly way. As a raw material, cellulose’s use is widely known and established in many areas. Additionally, its products/derivatives are recognized to have a far better environmental impact than fossil-based materials. Examples are textiles and packaging, where forest-based fibers may contribute to renewable and biodegradable substitutes for common synthetic materials and plastics. In this review, some of the main structural characteristics and properties of cellulose, recent green extraction methods/strategies, chemical modification, and applications of cellulose derivatives are discussed.

Juglans regia barks contain a diversity of phenolic compounds. Two of the most important groups of phenolic compounds are tannins, and flavonoids. These latter, possess different antioxidant, anti-inflammatory, and antibacterial properties. This paper explores the usefulness of dyeing cellulosic fabrics, namely cotton, with Juglans regia barks residues extract. The dyeing process proposed was assisted by microwave energy. The impact of the main dyeing conditions (percentage of cationizing agent, pH, dyeing duration, and microwave power) on the color strength (K/S) and the L*, a*, b*, C*, and h* coordinates were studied. Optimization experiments were carried out using a definitive screening type plan (MINITAB 19). It was found that the best conditions to achieve the dyeing of cellulosic fabrics were: a pH of 6.23; a percentage of cationizing agent of 6.5%; a microwave power of 690 W, and a dyeing duration of 4.5 min. [ABSTRACT FROM AUTHOR]

The difficulties associated with dyeing alginate fibers by conventional dyeing processes have been a major limitation hindering the large-scale application of alginate fibers in the textile industry. The main aim of this study is to use plasma equipment for free radical graft polymerization of methacryloyloxyethyl trimethylammonium chloride (DMC) to achieve a better dyeing effect on cationically modified alginate fibers by direct dyeing using a saltless dyeing process. The treated alginate fibers were dyed by direct dyes and characterized by SEM, FTIR-ATR, XPS, K/S value determination and single-fiber breaking strength analysis. The results show that the DMC was successfully grafted onto the alginate fibers, the modified alginate fibers had good dyeing ability with high K/S values; and the alginate fibers maintained their breaking strength of 2.33 cN/dtex after dyeing, corresponding to a decrease of only 15.5 % (red), 1.3 % (yellow), and 4.8 % (blue) compared to that of the original fiber. The dyed alginate fibers also showed good washing fastness, which was better than grade 4. All the results indicate that upon subjection to atmospheric plasma, DMC was efficiently embedded into the alginate fibers, making the fiber cationic and effectively overcoming the charge repulsion between the fiber and the dye under salt-free conditions. This study may provide a valuable method for the alginate fiber dyeing industry. [ABSTRACT FROM AUTHOR]

Developed pH-colorimetric indicators suffer from complex preparation, high cost, and interference in color observation. Here, modified fast-growing poplar (Populus L.) veneer was used as a direct substrate. A top-down lignin retention strategy was accomplished wherein mild alkali swelling and cationization were conducted synergically to develop a novel wood-based intelligent label via grafting quaternary ammonium groups and adsorbing BTB anions. When the concentration of NaOH was 1.5 % at the solid/liquid ratio of 1:30, the weight gain rate of the veneer increased to 7.03 %, while the porosity decreased by only 1.75 %, proving good dimensional stability. The adsorption capacity of BTB reached 8.504 mg/g, which was 38.30 times higher than that of the original veneer, and the b* achieved the lowest value of −23.13. Due to the ultra-high adsorption capacity of securely anchored BTB, the label showed high and stable pH-sensitivity and a favorable response to acetic acid gas. Its color varied from blue to green when the titratable acidity of fresh milk rose to 20.63°T (In China, the acidity of normal fresh milk should not exceed 20°T), accompanied by a tiny pH change. This study proposes a method for preparing pH-sensing wood film without delignification and bleaching, expanding the use of low-quality wood to a new area. [Display omitted] • Mild alkali swelling and cationization were combined to develop a novel label. • A top-down strategy was realized by quaternizing and electrostatic adsorbing BTB. • The label showed ultra-high adsorption capacity and high and stable pH sensitivity. • The label varied from blue to green when used to indicate the freshness of milk. [ABSTRACT FROM AUTHOR]

β-lactoglobulin (BLG) is the major whey protein with negative charges at neutral pH in aqueous media. Thus, the interaction with mucins, the major polyanionic component of mucus, is very weak due to the electrostatic repulsion between them. The present study postulates that cationization of BLG molecules may reverse the interaction characteristics between BLG and mucin from repulsive to associative. To this end, cationic-modified BLGs were prepared by grafting positively charged ethylenediamine (EDA) moieties into the negatively charged carboxyl groups on the aspartic and glutamic acid residues and compared with non-modified BLG upon mixing with porcine gastric mucin (PGM). To characterize the structural and conformational features of PGM, non/cationized BLGs, and their mixtures, various spectroscopic approaches, including zeta potential, dynamic light scattering (DLS), and circular dichroism (CD) spectroscopy were employed. Importantly, we have taken surface adsorption with optical waveguide lightmode spectroscopy (OWLS), and tribological properties with pin-on-disk tribometry at the sliding interface as the key approaches to determine the interaction nature between them as mixing PGM with polycations can lead to synergistic lubrication at the nonpolar substrate in neutral aqueous media as a result of an electrostatic association. All the spectroscopic studies and a substantial improvement in lubricity collectively supported a tenacious and associative interaction between PGM and cationized BLGs, but not between PGM and non-modified BLG. This study demonstrates a unique and successful approach to intensify the interaction between BLG and mucins, which is meaningful for a broad range of disciplines, including food science, macromolecular interactions, and biolubrication etc. [Display omitted] • Beta-lactoglobulins (BLGs) were cationized by grafting with ethylenediamine (EDA). • Cationic BLGs interact with porcine gastric mucin (PGM) associatively. • Lubricity of PGM was synergistically improved upon mixing with cationic BLGs. • Proteins should be not only cationic, but also flexible to associate with PGM. [ABSTRACT FROM AUTHOR]

Cotton cationization with low molecular weight or polymeric cationic modifiers allows the effective dyeing of cotton substrates with reactive dyes under salt-free and more environmentally friendly conditions. The current work focuses on the spectroscopic study of the intermolecular interactions, which dictate the physicochemical process associated with fabric dyeing. Water-soluble cationic copolymers of vinyl benzyl chloride (VBC) and vinyl benzyl triethylammonium chloride (VBCTEAM) have been used as cellulose cationic modifiers. Dye uptake was assessed using Remazol Brilliant Blue R and Novacron Ruby S-3B dyes. The study involves ATR-FTIR, UV-Vis, fluorescence, and XPS spectroscopy. The results of binary polymer-rich dye-polymer aqueous solutions or dye-polymer precipitates at stoichiometric charge-ratio revealed that the sulfonate/sulfate anions of the dyes interact with the cationic VBCTEAM units of the polymer via electrostatic interactions. Moreover, the comparative study of dye application on modified and unmodified fabrics suggests that, unlike the latter, where dyes are chemically bound to cellulose, electrostatic forces dominate the interaction of modified fabrics with dye molecules.

Micro/nanofibrillated celluloses (M/NFCs) have attracted considerable research interest over the past few decades, with various pretreatments being used to reduce energy consumption and/or increase fibrillation. To date, few studies have considered cationization as a pretreatment for their preparation. In this work, quaternary ammonium groups were attached to cellulose fibers by a direct reaction with 2,3-epoxypropyltrimethylammonium chloride or by a two-step method (periodate oxidation + Girard's reagent T). The cationic fibers with degrees of substitution (DS) between 0.02 and 0.36, were subjected to homogenization treatment. The morphological properties, chemical composition, and rheological behavior were evaluated to assess the effect of DS and the effect of the cationization method (for samples with similar DS). The two-step cationization resulted in significant degradation of the cellulose structure, leading to the formation of short fibrils and solubilization of the material, ranging from 6% to almost complete solubilization at a DS of 0.36. Direct cationization resulted in longer fibrils with an average diameter of 1 μm, and no significant cellulose degradation was observed, leading to a more cohesive gel-like material (at 1 wt%). These observations clearly show the strong influence of the cationization method on the final properties of the cationic cellulosic materials. • Cellulose fibers were cationized with quaternary ammonium groups. • Cationic fibrillated celluloses were produced by high-pressure homogenization. • CHPTAC cationization resulted in long fibrils and a gel-like material; • A two-step cationization resulted in short fibrils and cellulose solubilization. [ABSTRACT FROM AUTHOR]

Cationization of cotton fabrics was performed by exhaustion procedure utilizing four different reagents provided with quaternary ammonium groups: poly diallyldimethylammonium chloride (PDDACl), poly acrylamide-co-diallyldimethylammonium chloride (PAcD), poly[bis(2-chloroethyl) ether-alt-1,3-bis[3-(dimethylamino)propyl]urea] quaternized (P42) and 3-chloro-2-hydroxypropyl trimethyl ammonium chloride (CHPTAC). Pretreated samples were dyed using Reactive Red 195 dye. The cationic fabrics were analyzed by colorimetric and fastness properties, zeta potential, SEM, FTIR and an estimate of the bactericidal effect. Cationic cotton treated with PDDACl and CHPTAC showed a higher affinity for the reactive dye, with color strength (K/S) values varying from 41 to 48, against 32 for conventional dyeing. P42 presented competitive results with K/S of 27–28. The cationic dyeing considerably reduced the amount of effluent, especially for the CHPTAC samples, which requires a single washing bath for complete removal of unfixed dye. The PDDACl and P42 samples presented bactericidal activity. [ABSTRACT FROM AUTHOR]

Free radical graft polymerization of diallyldimethylammonium chloride (DADMAC) on cotton was employed to substantially improve the dyeability cotton with reactive dyes under salt-free conditions. The effects of plasma-induced graft polymerization of DADMAC on cotton, followed by dyeing with different reactive dyes, was characterized by Fourier transform infrared spectroscopy. A color fastness wash test was conducted to evaluate the effectiveness of cotton cationization on reactive dye fixing. The results show that the salt-free dyeing process with reactive dyes was effective after cationization modification, and the dye uptake rate and dyeing depth are higher than the conventional dyeing techniques. [ABSTRACT FROM AUTHOR]

By using the electro-spinning process on natural polymers, it is possible to obtain biodegradable membranes with potential applications in filters and scaffolds for tissue engineering. In this study, a comparison was made between the respective chemical, physical and thermal properties of the fibers from two sources of starch: One derived from a local, indigenous variety of potato (Diacol Capiro), native to the Boyacá region of Colombia (from here on referred to as “local starch”); the other, commercially available starch. A cationization of fibers was also carried out on the two starches. Chemical, physical and thermal properties were analyzed by Fourier transform infrared (FTIR), scanning electron microscopy (SEM), X-ray diffraction (DRX), thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The results showed the fibers were cationized with a highly amorphous state, with a heat resistance of 300°C from physicochemical changes generated in the fibers.