Mercerized Cotton Fibers Research Articles

A cleaner production process for high performance cotton fabrics

High performance cotton fabrics with color, luster and wrinkle resistance are manufactured by three steps. The coloration, wrinkle resistance and luster finishing consume a large number of resources, and generate a huge amount of colored wastewater. The present research reports a cleaner process for dyeing, wrinkle resistance and luster finishing of cotton fabrics. Cotton fabrics were dyed at 35 °C for 15 h with multifunctional reactive dye solutions of high concentrations. Scanning electron microscope images show the fiber cross sections became circular like the mercerized cotton fibers, and the fabrics exhibited nice luster and wrinkle resistant ability. For fabrics with light and middle color, a certain amount of 1,3,5-triacryloyhexahydro-1,3,5-triazine was added into the dye liquor to make the fiber cross section become circular and to make the wrinkle recovery angle reach more than 260° to obtain good wrinkle resistant ability. When the padded fabrics were steamed at 102 °C for 3 min instead of fixing at 35 °C for 15 h, the wrinkle recovery angle also reached 266°. The breaking strength of dyed fabrics decreased with increasing the dye and 1,3,5-triacryloyhexahydro-1,3,5-triazine concentrations. The enhancement of wrinkle resistance of dyed fabrics is due to the crosslink effect of the dye molecules with cellulose macromolecules. This one-step process will save a significant amount of energy and water, and reduce the effluent discharged.

Segal crystallinity index revisited by the simulation of X-ray diffraction patterns of cotton cellulose Iβ and cellulose II

The Segal method estimates the amorphous fraction of cellulose Iβ materials simply based on intensity at 18° 2θ in an X-ray diffraction pattern and was extended to cellulose II using 16° 2θ intensity. To address the dependency of Segal amorphous intensity on crystal size, cellulose polymorph, and the degree of polymorphic conversion, we simulated the diffraction patterns of cotton celluloses (Iβ and II) and compared the simulated amorphous fractions with the Segal values. The diffraction patterns of control and mercerized cottons, respectively, were simulated with perfect crystals of cellulose Iβ (1.54° FWHM) and cellulose II (2.30° FWHM) as well as 10% and 35% amorphous celluloses. Their Segal amorphous fractions were 15% and 31%, respectively. The higher Segal amorphous fraction for control cotton was attributed to the peak overlap. Although the amorphous fraction was set in the simulation, the peak overlap induced by the increase of FWHM further enhanced the Segal amorphous intensity of cellulose Iβ. For cellulose II, the effect of peak overlap was smaller; however the lower reflection of the amorphous cellulose scattering in its Segal amorphous location resulted in smaller Segal amorphous fractions. Despite this underestimation, the relatively good agreement of the Segal method with the simulation for mercerized cotton was attributed to the incomplete conversion to cellulose II. The (1−10) and (110) peaks of cellulose Iβ remained near the Segal amorphous location of cellulose II for blends of control and mercerized cotton fibers.

Synthesis of twisted ribbon-like carbon, carbon microtubes and carbon rod from mercerized cotton fiber

In this study, we used mercerized cotton fibers as carbonization precursors to fabricate carbon materials having different structures. The morphologies of the synthesized carbon materials were successfully controlled by varying the mercerization time. Twisted ribbon-like carbon structures, carbon microtubes, and carbon rods could be synthesized by carbonizing non-mercerized cotton fibers, cotton fibers mercerized for 40min, and fully mercerized cotton fibers (i.e., fibers mercerized for 60min), respectively. Interestingly, along with the morphological changes, the specific surface areas of these carbon materials were also changed to 203.7, 726, and 276.7m2/g, respectively. This method of fabricating carbon materials should lead to the synthesis of novel, structured carbon materials with various functionalities as it exploits both the natural structure of cotton fibers and artificial chemical processes.

Preparation and characterization of cellulose nanofibers from partly mercerized cotton by mixed acid hydrolysis

Cellulose nanofibers with a diameter of 70 nm and lengths of approximately 400 nm were fabricated from partly mercerized cotton fibers by acid hydrolysis. Morphological evolution of the hydrolyzed cotton fibers was investigated by powder X-ray diffraction, Fourier transform infrared analysis and field emission scanning electron microscopy. The XRD results show that the cellulose I was partially transformed into cellulose II by treatment with 15 % NaOH at 150° for 3 h. The crystallinity of this partially mercerized sample was lower than the samples that were converted completely to cellulose II by higher concentrations of NaOH. The intensities of all of the diffraction peaks were noticeably increased with increased hydrolysis time. Fourier transform infrared results revealed that the chemical composition of the remaining nanofibers of cellulose I and II had no observable change after acidic hydrolysis, and there was no difference between the hydrolysis rates for cellulose I or II. The formation of cellulose nanofibers involves three stages: net-like microfibril formation, then short microfibrils and finally nanofibers.

Transitional Properties of Cotton Fibers from Cellulose I to Cellulose II Structure

Mercerized fibers were prepared from native cotton fabrics via NaOH solution treatment at different concentrations. Mercerization led to transformation of the crystal structure of cotton fibers from cellulose I to II when the NaOH concentration was greater than 10 wt%. In addition, the cotton fibers were converted into a swollen and rough state after mercerization treatment. The results of Fourier transform infrared spectrometry and wide-angle X-ray diffraction indicated that the cellulose molecular structure changed (e.g. the degree of disorder of O-H stretching vibration increased, while the crystallinity index decreased) in the process of mercerization. Thermogravimetric analysis determined that the cellulose II fibers were more thermally stable than the cellulose I fibers. The mechanical properties of cellulose fiber-reinforced polyethylene oxide (PEO) composites showed that both original and mercerized cotton fibers enhanced the tensile strength of the PEO matrix. These properties directly contributed to the advantages of mercerized textile products (e.g. higher luster, holds more dye, more effectively absorbs perspiration, and tougher under different washing conditions).

Comparative properties of cellulose nano-crystals from native and mercerized cotton fibers

Stable aqueous suspensions of cellulose nano-crystals (CNCs) were fabricated from both native and mercerized cotton fibers by sulfuric acid hydrolysis, followed by high-pressure homogenization. Fourier transform infrared spectrometry and wide-angle X-ray diffraction data showed that the fibers had been transformed from cellulose I (native) to cellulose II (mercerized) crystal structure, and these polymorphs were retained in the nanocrystals, giving CNC-I and CNC-II. Transmission electron microscopy showed rod-like crystal morphology for both types of crystals under the given processing conditions with CNC-II having similar width but reduced length. Freeze-dried agglomerates of CNC-II had a much higher bulk density than that of CNC-I. Thermo-gravimetric analysis showed that CNC-II had better thermal stability. The storage moduli of CNC-II suspensions at all temperatures were substantially larger than those of CNC-I suspensions at the same concentration level. CNC-II suspensions and gels were more stable in response to temperature increases. Films of CNC and Poly(ethylene oxide) were tested. Both CNC-I/PEO and CNC-II/PEO composites showed increased tensile strength and elongation at break compared to pure PEO. However, composites with CNC-II had higher strength and elongation than composites with CNC-I.

Differences Between Cotton and Viscose Fibers Crosslinked with BTCA

Presently polycarboxylic acids are being used for cellulose crosslinking. Among these, 1,2,3,4-buthanetetracarboxylic acid (BTCA) is the most effective in combination with a corresponding catalyst. In this research, a comparison of crosslinking effects on mercerized cotton fibers and viscose was identified using certain physical— chemical methods. The extent of crosslinking was evaluated using Fourier transform infrared (FT-IR) spectroscopy. The crosslinking of cellulose increases wrinkle resistance and reduces the mechanical properties, therefore, for this purpose the wrinkle recovery angle and the breaking force, was evaluated together with breaking elongation. When considering the crosslinking mechanism, those additional free BTCA carboxyl groups that are accessible in the cellulose polymer reflect the effectiveness of cotton-fiber crosslinking. The evaluation of accessible carboxyl was performed using the methylene blue method, where the adsorption of methylene blue dye on the cellulose material was monitored spectroscopically. The purpose of this research is mainly (i) to evaluate how different types of cellulose matrices/substrates influence the crosslinking of fibers crosslinked with different mass fractions of BTCA and (ii) to establish the most appropriate mass fraction of BTCA in the impregnation bath for sufficient crosslinking of mercerized cotton fibers, as well as viscose.

Structural change in mercerized cotton fibers on cellulase treatment

AbstractCotton fibers treated with liquid ammonia and sodium hydroxide were hydrolyzed with crude cellulase. The structural change in the fibers due to the cellulase treatment was examined in relation to the apparent affinity of Congo Red. The cellulose III crystalline structure collapsed and generated intermediate‐molecular‐ordered regions on cellulase treatment. Adsorption of Congo Red occurred on the crystallite surfaces of cellulose II and cellulose III that was transformed from cellulose II. The fiber, the dominant crystallite phase of which was cellulose III that was transformed from cellulose II, had a considerably increased apparent affinity after cellulase treatment. The intermediate structure on the crystallite surface was associated with the adsorption of Congo Red in the cases of cellulose II and cellulose III. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 1675–1680, 2001

Hydrolysis of mercerized cotton fibers due to cellulase treatment

Cotton fibers mercerized under the relaxed state were hydrolyzed with crude cellulase. The mercerization treatment examined included ammonia treatment, sodium hydroxide treatment, and two combined treatments using ammonia and sodium hydroxide. Crystalline regions of the mercerized fibers were hydrolyzed in the first step of hydrolysis. In this step, ammonia treatment decreased the crystallite size to a great extent due to the hydrolysis of the cellulose III crystalline phase. Cellulase treatment rendered the crystallite surface highly accessible to water molecules. The crystalline phase was closely related to water sorption of cellulase-treated fibers. The sequence of treatment had an influence on the fiber structure in the case of the combined mercerization treatment with ammonia and sodium hydroxide. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 78: 364–370, 2000

Changes in dyeability and morphology of cotton fiber subjected to cellulase treatment

Unprocessed and mercerized cotton fibers were treated with commercial crude cellulase. The changes in the dyeability and structural features of the fiber due to cellulase treatment were studied. The dyeability was examined in terms of uptake of three reactive dyes and the apparent affinity of Congo Red to cotton fiber. The dyeability of the unprocessed fiber was assumed to be influenced by some impurities present in it. This fiber probably resembled polynosic fiber in molecular aggregate at a certain stage of hydrolysis. Mercerized cotton showed a similar pattern in dyeability as weight loss increased, regardless of dye species. Enzyme more easily penetrated the mercerized fiber than the unprocessed fiber. Cellulase treatment influenced the X-ray crystalline reflection pattern for the mercerized fiber but nominally influenced that for unprocessed fiber. Scanning electron micrographs revealed that cellulase treatment caused swelling of the fibrils. They also revealed that the disordered regions between the fibrils in the secondary walls were removed at low weight loss for the unprocessed fiber. The mercerized fiber at high weight loss had large cracks oblique to the fiber axis and showed no individual fibrils in the secondary wall. The primary wall was removed in the initial stage of hydrolysis for both the unprocessed and mercerized fibers. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 65: 155–164, 1997

Restoration of Hydrophilicity of Field-Opened Cotton Fibers by Cyanoethylation Treatment.

Field-opened American cotton fibers were treated with acrylonitrile after impregnation with aqueous sodium hydroxide. By this treatment the water absorbency and the amount of bound water as determined by DSC were increased and approached those of never-dried cotton. As for tensile strength, the increase in dry strength was higher than that of wet strength. On DSC cooling curves peak II, ascribable to freezable bound water, was observed as a small shoulder for field-opened and mercerized cotton fibers. However, this peak disappeared after the acrylonitrile treatment. Those treated fibers showed a nearly circular cross-sectional shape. Lumen and convolution could hardly be observed.

Factors Affecting the Tensile Properties of Nonmercerized and Mercerized Cotton Fibers

When a G. hirsutum cotton fiber was suspended under tension in water and then allowed to dry without removing the stress, its strength increased and its extensibility decreased. If the sample was slack mercerized before the treatment, its strength and extensibility changes were not as marked. The altered properties of the nonmercerized cotton are ascribed to the water inducing plasticization of the fiber, thus permitting the structural units of the sample to readjust as its convolutions began to untwist and as creep occurs. By comparing the properties of the nonmercerized and mercerized counterparts, we propose that the increased strength and extensibility of cotton with slack mercerization is due to the swelling effects of this treatment, which causes un twisting of the fiber and reduces its degree of crystallinity and its crystallite lengths.

Effect of Dimethyloldihydroxyethyleneurea on the Properties of Cellulosic Fibers

We have determined the effect of dimethyloldihydroxyethyleneurea (DMDHEU) on the tensile properties, brittleness, and flex fatigue properties of cotton fibers before and after slack mercerization. The tensile strength and extensibility of nonmercerized fibers decrease with DMDHEU application, but there are distinct differences in the effect of mercerization on the tensile properties of the fibers depending on whether a G. barbadense or G. hirsutum sample is being studied. We explain the effects of cross linking on the tensile properties of nonmercerized and mercerized cotton in terms of current knowledge of their fine structure, and we suggest that morphology also plays an important role in determining the effect of resins on such properties. The brittleness of nonmercerized and mercerized cotton fibers as measured by the breaking twist angle (BTA) method increases as DMDHEU content increases. BTA is correlated with various tensile parameters. The correlation coefficient falls in the order extensibility > nominal rupture energy > tenacity > secant modulus. When considering the effect of resins on the tensile properties of cotton fibers, yams, or fabrics, we recommend that more attention be paid to extensibility. In general, it appears that for cotton at low DMDHEU contents, a premercerization treatment retains the flex life of the sample at a value close to that of the nonresin-treated, nonmercerized control.

Further Evidence for the Presence of Cellulose I and II in the Same Cross Section of Partially Mercerized Cotton Fibers

Further Evidence for the Presence of Cellulose I and II in the Same Cross Section of Partially Mercerized Cotton Fibers

The Effect of Cotton Mercerization on Cotton/Polyester Blends

The effect of using mercerized cotton fibers on the strength of yarns and fabrics made of cotton/polyester blends was studied. Cotton fibers were mercerized by treating them with 24% NaOH solution for two minutes. Three levels of blends were used. The blends were prepared using both unmercerized and mercerized cotton fibers for comparison purposes. The results show significant improvement in the strength of the yarns and fabrics having mercerized cotton over those with unmercerized cotton.

Orientation-Disorientation Effects in Tensioned, Mercerized Cotton. The Pretreatment of Yarns for Wash-Wear Fabrics of High Strength and Durability

Slack mercerization of cotton, with restretching to various degrees in the mercerizing alkali, was compared to merceriza tion at constant, preselected lengths as a method of yarn pretreatment. Fabrics were woven of these pretreated 2-ply yams and were crosslinked with DMEU to a wrinkle recovery of 270°-286° (W + F). In certain cases little or no loss of strength occurred during DP finishing, and the yarn-mercerized fabrics possessed greater strength after crosslinking than ordinary fabric not crosslinked at all. Moreover, after 20 launderings several of the experimental wash-wear fabrics equalled in strength the unmercerized, uncrosslinked, unlaundered fabrics prepared as controls. X-ray orientation, yarn strength, and elongation, as well as the degree of stretching during yarn pretreatment, were correlated with yarn and fabric strength after crosslinking and after fabric laundering. In yarn slack-mercerized and restretched to 91% of normal length, both the strength and the elongation after crosslinking equalled the values for unmercerized yarn before cross linking. The same effect occurred in fabrics woven from these yarns. Evidence is presented that domains of swelled and shrunken cellulose remain in mercerized cotton fibers even after tension has been applied to orient the crystallites and straighten the fibrillar spirals of the alkali-wet cotton. The most effective yarn pretreatment, for increased strength retention after DMEU crosslinking, was slack mercerization followed by restretching to 103% of normal length. In fabrics woven of these yarns, covalent crosslinking by DMEU actually increased the durability, as measured by strength retained during multiple launderings. Yarn commercially mercerized to 102% of normal length also was highly suitable. The increased yarn length obtained in this kind of pretreatment could largely offset the cost of yarn mercerization, leaving the cost of yarn plying as the principal item of expense.

Tension and Resin-Treatment Effects on Properties of Scoured and Mercerized Cotton Fibers and Fabrics of Different Constructions

Fabrics of printcloth weight in plain and basket weave were crosslinked with dimethylolethyleneurea to 2, 5, and 10% add-on. Specimens were dried slack or under tension before curing. The amount of crosslinking, controlled by resin pickup, produced reasonably consistent nitrogen contents in samples when other parameters were varied. Among the properties measured were fiber density, fabric thickness and area changes, fabric tensile and wrinkle recoveries, and single- fiber tenacity and tensile recovery. Relationships of properties to nitrogen contents and among various physical proper ties were frequently influenced by tension, fabric construction, and pretreatment.

ON THE SUBMICROSCOPIC CHANGES OF COTTON FIBERS DUE TO MERCERIZATION

Hereunder is given a report of observations of cotton fibers performed in order to obtain the gradual changes of their surface during the process of mercerization. The fiber surface was carefully observed through an electron microscope. Conditions of mercerization is changed by the concentration of sodium hydroxide, and the time and temperature of the treatment. The following facts have been elucidated as the result:1. The deep original wrinkles, each 0.1_??_1 microns apart swell under alkali action and have a tendency to vanish rapidly. Under ordinary conditions they vanish completely.2. The larger part of cuticle layers that form the surface of raw cotton fiber are removed during the preliminary scouring process and they are completely removed under the mercerization treatment.3. The microfibrils lying within the cellulose layers swell under alkali action, giving the surface of the fiber consequence granuler or porous appearances.The surface structure mentioned in heading 3 above has been found characterictic to cotton fibers whenever they are subjected to mercerization treatment, not only being the case with scoured cotton but with raw cotton or with dewaxed cotton. What is to account for this characterstic change of the surface structure of cotton fibers? Taking into consideration the results of the experiments worked with dyestuff absorptiveness on mercerized cotton fibers, it is concluded as follows:Mercerization process presupposes alkali action. The alkali-soluble hemicelluloses within the fiber oozes out to the surfaces, there to agglutinate on them instead of being washed off.

The system cellulose—methanol

AbstractThe determination of nonsolvent methanol by a drying technique on cotton and mercerized cotton fibers and a comparison with corresponding values of nonsolvent water showed that methanol forms solvates only with half the number of hydroxyl groups available for hydrate formation in the amorphous part of the fibers. It showed, furthermore, that methanol does not form solvates with hydroxyl groups in semicrystalline regions of mercerized fibers. The method also permits determination of nonsolvent methanol with fibers which reach equilibrium from the wet side. A schematic approach to fiber structure gives good agreement between the quantities of nonsolvent water and methanol and molar integral heats of wetting, respectively. Both characteristics permit an estimation of fiber composition of natural cellulose fibers.