The dyeing process commonly deteriorates the luster of pre-mercerized cotton fabric, so post-mercerization processes are regularly applied to compensate for this. Herein, the influence of combining ...pre-mercerization with CS (caustic solution) or LA (liquid ammonia) and post-mercerization with CS or LA on the morphological structure, dyeing performance, tensile strength, and stiffness of woven cotton fabric was investigated. The crystallinity index values greatly decreased from 73.12 to 51.25, 58.73, 38.42, and 40.90% after the combined mercerization processes of LA-LA, CS-CS, LA-CS, and CS-LA, respectively. Additionally, the CS-LA- and LA-CS-treated samples exhibited a mixture of cellulose II and cellulose III allomorphs. The combined mercerization processing of cotton fabric resulted in slightly worse thermal stability. The LA and CS pre-mercerization processes increased the dye exhaustion, although the former decreased the dye fixation rate while the latter increased it by 4% for both dyes. The color strength of the dyed cotton fabric increased after both post-mercerization processes. Moreover, the fabric stiffness and mechanical properties showed an increasing trend due to the combined mercerization efforts.
Eco-friendly composites can be prepared by substituting man-made synthetic fibres with various types of cellulosic fibres. Sugar palm-derived nanocrystalline cellulose is a potential substitute. The ...most important factor in determining a good nanofiller reinforcement agent that can be used in composites is the character of the nanofiller itself, which is affected during a preliminary treatment. Thus, to gain better nanofiller properties, the delignification (NaClO2 and CH3COOH) and mercerization (NaOH) treatments must be optimized. The main objective of this study was to identify the effects of the delignification and mercerization treatments on sugar palm fibre (SPF). In addition, the characteristics of the SPF for the preparation of the hydrolysis treatment to produce nanocrystalline cellulose (NCC) for reinforcement in polymer composites were examined. Sugar palm cellulose (SPC) was extracted from the SPF, and its structural composition, thermal stability, functional groups, and degree of crystallinity were determined via field emission scanning electron microscopy (FESEM), thermogravimetric analysis (TGA), Fourier transform infrared (FTIR) spectroscopy, and X-ray diffraction (XRD), respectively. The density, moisture content, chemical composition, and structure of the SPC were also analysed.
Natural dyes are not harmful to the environment owing to their biodegradability. For dye application to textiles, salts are necessary as mordant or electrolytes and make an environmental impact. In ...this paper, the influence of cationization during mercerization to the dyeing of cotton fabric with natural dye from
was researched. For this purpose, bleached cotton fabric as well as fabric cationized with Rewin OS was pre-mordanted using iron(II) sulfate heptahydrate (FeSO
·7H
O) and dyed with natural cochineal dye with and without electrolyte addition. For the characterization of surface changes after cationization, an electrokinetic analysis on SurPASS was performed and compared to pre-mordanting. For determination of dye exhaustion, the analysis of dye solution was performed on a UV/VIS spectrophotometer Cary 50 Solascreen. Spectrophotometric analysis was performed using a Datacolor 850 spectrophotometer, measuring remission "until tolerance" and the whiteness degree, color parameters, color depth (K/S), and colorfastness of dyed fabric were calculated. Levelness was determined by visual assessment. Cationized cotton fabrics showed better absorption and colorfastness. Pre-mordanting and cationization showed synergism. The electrolytes improved the process of dye absorption. However, when natural dyeing was performed on cotton fabric cationized during mercerization, similar chromacity, uniform color, and colorfastness were achieved with and without electrolyte, resulting in pure purple hue of cochineal. For achieving a violet hue, pre-mordanting with Fe-salt was needed. Therefore, salt can be reduced or even unnecessary, which makes this process of natural dyeing more environmentally friendly.
•Gradual polymorphoric transformation from polymorph of Cellulose I to II takes place with the evidences of decreasing crystallite size of Cellulose I and growing crystallite size of cellulose II in ...the transition conditions.•Nano-size induced polymorphic transformation, which is strongly correlated with the sample's crystallite size, plays a role in reducing the critical concentration required for polymorph conversion.•Morphology of individual CNC was imaged by TEM after redispersion of mercerized CNC samples by TEMPO oxidization.•Morphology of cellulose II exhibited interconnected granules, indicating one cellulose molecular chain may involve in several crystallites forming.•This work sheds some light on the mechanism of polymorphism transformation of cellulose I to II.
Polymorphic and morphological transformations of cellulosic materials are strongly associated to their properties and applications, especially in the case of emerging nanocelluloses. Related changes that take place upon treatment of cellulose nanocrystals (CNC) in alkaline conditions are studied here by XRD, TEM, AFM, and other techniques. The results indicate polymorphic transformation of CNC proceeds gradually in a certain range of alkali concentrations, i.e. from about 8% to 12.5% NaOH. In such transition alkali concentration, cellulose I and II allomorphs coexists. Such value and range of the transition concentration is strongly interdependent with the crystallite size of CNCs. In addition, it is distinctively lower than that for macroscopic fibers (12–15% NaOH). Transmission electron microscopy and particle sizing reveals that after mercerization CNCs tend to associate. Furthermore, TEMPO-oxidized mercerized CNC reveals the morphology of individual nanocrystal of the cellulose II type, which is composed of some interconnected granular structures. Overall, this work reveals how the polymorphism and morphology of individual CNC change in alkali conditions and sheds light onto the polymorphic transition from cellulose I to II.
The influence of caustic mercerization (C
M
) and liquid ammonia (L
A
) treatments on the properties of reactively dyed cotton fabrics were schematically studied. The cotton fabrics were dyed using ...different commercial reactive dyes such as Reactive Red 2 (R
2
), Reactive Blue 21 (B
21
), and Reactive Orange 5 (O
5
) via industrial dyeing procedures. The dyed fabrics were then treated using 260 g·L
−1
of caustic soda solution at 23 °C for 180 s and pure L
A
at −40 °C for 3 min in slack and tension conditions. The dyeing properties of the fabrics such as dye removal percentage, color strength, color uniformity, reflectance, and fastness properties (washing, rubbing, hot pressing and light) were examined. The changes in tensile strength, elongation, bending property, decomposition temperature, crystal structure, and surface morphology of the samples were also investigated using a tensile strength tester, thermogravimetric analyzer (TGA), scanning electron microscope (SEM), and an X-ray diffractometer (XRD). Results revealed that the fabric dyed with O
5
showed the best stability in C
M
and L
A
treatment, and the color strength and color uniformity of the dyed fabrics increased extensively after both treatments, while the reflectance of the fabrics decreased. The washing and rubbing fastness of the fabrics were also improved, which was mainly attributed to the diffusion of the dye molecules inside the fibers and enhanced bonding between fiber and dye molecules. The fastness to hot pressing and light was unaffected and all the samples retained fastness rating between 4 and 5 after being post-treated with the C
M
and L
A,
respectively. The tensile strength of the fabrics improved from 287 to 291 and 301 N, and the elongation at break increased from 11 to 21.5 and 26% after C
M
and L
A
treatment in slack conditions, respectively. Additionally, the tensile strength of the fabrics improved from 287 to 312 and 330 N, and the elongation at break increased from 11 to 12% after applying tension during both treatments. However, the total bending length and total flexural rigidity of the samples slightly increased after both the treatments either treated with or without tension, which was mainly attributed to the orientation of the cellulose microfibril angle along the fiber axis. The surface morphology and X-ray diffraction examination revealed that the treated samples consisted of smooth rod-like structure and the cellulose I allomorph was converted to cellulose II and cellulose III after C
M
and L
A
treatments. This developed treatment method could have application potential within the textile wet-processing industry, as it could be used to improve the dyeing properties and mechanical properties of cotton fabrics.
Graphic abstract
•Mercerization successfully controlled the dimensions of native BNC conduits.•Superior mechanical properties of BNC conduits were achieved via mercerization.•Mercerized BNC (MBNC) conduits exhibited ...nice hemocompatibility in absence of bioactive compounds.•MBNC conduits satisfied a long-term patency over 16 weeks in a rat abdominal aorta model.
Bacterial nanocellulose (BNC) is a natural polysaccharide synthesized principally by Komagataeibatacter xylinus which can be formed into tubes and other shapes through the use of special bioreactors. Although tubular BNC has considerable potential as a small-caliber vascular graft (<6 mm), its poor mechanical properties in its hydrogel form, lack of compliance, and its thick walls that do not match natural vessels limit their potential clinical use and long-term patency rate after implantation. Mercerization is an approach in which an alkaline treatment changes the chemistry of BNC products. Following mercerization, tubular BNC grafts exhibited greater mechanical strength combined with thinner walls. Volumetric reduction of the tubular BNC was effective (by nearly 90%) when using a NaOH concentration greater than 10% (w/v), which caused fewer platelets to adhere to the luminal surface. Mercerized tubular BNC (MBNC) promoted the proliferation of endothelial cells in vitro. The MBNC obtained using 20% NaOH was selected for transplantation within a rat abdominal aorta model. Normal blood flow was observed for 16 weeks, indicating that the MBNC conduit maintained long-term patency. The results indicate that mercerization can control the size of tubular BNC and thus the MBNC conduit is a promising candidate for blood vessel replacement.
Cellulose II hydrate was prepared from microcrystalline cellulose (cellulose I)
via its mercerization with 5 N NaOH solution over 1 h at room temperature followed by washing with water. The structure ...of cellulose II hydrate changed to that of cellulose II after drying. Compared with cellulose II, cellulose II hydrate exhibited a slightly (8.5%) expanded structure only along the
1
1
¯
0
direction. The hydrophobic stacking sheets of the cellulose II were conserved in the cellulose II hydrate, and water molecules could be incorporated in the inflated two-chain unit cell of cellulose II hydrate. Enzymatic hydrolysis of cellulose I, cellulose II hydrate, and cellulose II was carried out at 37 °C using solutions comprising a mixture of cellulase and β-glucosidase. The hydrolysis of cellulose II hydrate proceeded much faster than the hydrolysis of the other two substrates, while the saccharification ratio of cellulose II was only slightly higher than that of cellulose I. The alkaline mercerization treatment was also applied to sugarcane bagasse. After its direct mercerization, the cellulose in bagasse was converted from cellulose I to cellulose II hydrate, and then to cellulose II after drying. Similar to in the case of microcrystalline cellulose, the rate of the enzymatic hydrolysis of the mercerized bagasse without drying (cellulose II hydrate) was much faster than the enzymatic hydrolysis of the other two substrates. Thus, the wet forms of cellulose and cellulosic biomass after mercerization, and after hydrolysis with cellulolytic enzymes, afforded superior products with extremely high degradability.
•Bamboo advantages including growing fast, strong mechanical properties, and low-cost.•Plantation, harvesting and processing of bamboo has global socio-economic benefits.•The increase in the alkali ...concentration reduces wax, ash contents, and cellulose.•There is an optimum NaOH concentration level, immersion time, and temperature level.•Excessive alkali concentration damaged the fibers and affects the mechanical properties.
Applying bamboo fibers into the composite reinforced concrete governs some significant drawbacks, including inadequate adhesion between fiber and matrix interface, and hydrophilic nature. Thus, the mercerization of bamboo fibers is suggested to overcome these limitations. In this review, the thermal and mechanical properties of alkalized bamboo fibers have been evaluated. It was concluded that alkalization treatment of bamboo fibers could provide enhanced bio-composites properties up to a great extent. Besides, the betterment of the thermal stability and mechanical properties of the alkalized bamboo fibers and its composite depends closely on the temperature level, immersion time, and NaOH concentration percentage.
In this study,the microstructure and chemical characterization of untreated and alkaline treated plant-basednatural fibers such as pineapple, kenaf, flax, hemp were performed. The objective of the ...present work is to understand the effectiveness of mercerization on the characteristics of plant-based natural fibers. First, the raw untreated fibers was subjected to treatment in 5% NaOH solution for the removal of surface impurities and thereby enhancing the hydrophobic nature of fibers. After NaOH treatment, the fibers were washed 3–4 times with distilled to remove the sodium hydroxide settlements during mercerization. The microstructure analysis of the untreated and treated fibers was performed using the Field Emission Scanning Electron Microscope (FESEM). Moreover, the elemental composition was studied using the Energy Dispersive X-ray Spectroscopy (EDS).Results from the FESEM analyses revealed that the alkaline treatment of raw fibers using NaOH helped in the removal of surface impurities, lignin, and hemicellulose. Moreover, the elemental composition obtained from EDS analysis showed an increased amount of carbon content in untreated fibers.
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