Rayon Fabrics Research Articles

Active carbons as catalysts for liquid phase reactions

This paper gives three examples of applications of activated carbons, including synthetic carbons obtained from polymers, in selective liquid phase organic reactions. It is shown that ruthenium supported on activated carbon cloths (ACC) obtained by carbonisation of woven rayon fabric are very selective in the hydrogenation of glucose to sorbitol. This is attributed to an easy mass transfer from the micropores to the liquid phase which favours the fast desorption of sorbitol avoiding epimerisation to mannitol. Synthetic carbons obtained by carbonisation of cross-linked phenolic resins are active in the oxidation with air of cyclic ketones (cyclohexanone, cyclododecanone, 3,3,5-trimethylcyclohexanone) to the corresponding dicarboxylic acids. The activity and selectivity depend upon treatments favouring the presence of surface functional groups, particularly quinone/carbonyl groups. This paper also shows that activated carbons obtained from natural sources can be modified by thermal treatments favouring the presence of basic sites which improve the rate of the oxidative decarboxylation of N-phosphonomethyl iminodiacetic acid to glyphosate. The nitrogen-containing basic functions generated by high temperatures thermal treatment of the activated carbon in NH 3 are particularly active.

Physical Properties of Cellulosic Fibers Treated under Ultra-High Pressure

It was found out that the cellulosic fibers could be controlled washing shrinkage by treated under the ultra-high pressure, over 100MPa. In this study, we investigated the shrinkage of the cellulosic fabric under high pressure treatment and the simultaneous change in their molecular-level structures and their physical properties. The high-pressure shrinkage for cotton fabric decreased with the treated temperature and the treated pressure, which enhanced the washing shrinkage. On the other hand, the shrinkage of rayon fabric was almost independent of the treated temperature and pressure. The tenacity of treated fabrics decreased after the treatment at high temperature and high pressure. Moreover, the molecular weight of a cellulose molecule in cotton decreased after the high-pressure treatment. The crystalline structure unchanged through the treatment, but the physical properties of the amorphous region was affected by the treatment, which was confirmed from dynamic loss tangent.

Antibacterial Effect and Color Fastness of Fibers Treated with Extract from Aloe arborescens (Kidachi Aloe) Dry Leaves

The eight kinds of standard fabric, cotton, nylon, acetate, wool, rayon, acryl, silk and polyester, were treated with the extract of Aloe arborescens (Kidachi aloe) dry leaves under an alkaline condition, respectively. Among them, the treated silk, wool and rayon fabrics showed deep colors, and moreover, the silk and rayon ones had strong antibacterial activity. They were tested on their color fastness against ultraviolet, washing, water, dry-cleaning or dry-heating, and then, their antibacterial activity was inspected again. As a result, it was cleared that the treated silk fabric keeps more effective antibacterial activity than the rayon one after the color fastness tests. In addition, it was found that its antibacterial activity was more effective on Staphylococcus aureus than on Klebsiella pneumonoiae. For silk, the extract of Aloe arborescens dry leaves was suggestted to have a possibility as a practical antibacterial agent.

Biodegradability of cellulose fabrics

AbstractBiodegradability of cellulose fabrics was evaluated by use of a soil burial test, an activated sewage sludge test, and an enzyme hydrolysis. Surface changes after biodegradation were observed by optical microscopy. From X‐ray diffraction analysis (XRD), changes in the crystallinities and the internal structures as a result of degradation were also investigated. It was shown that biodegradability decreased in the following order: rayon > cotton ≫ acetate. Rayon fibers, which have a low crystallinity and a low degree of orientation, showed the highest biodegradability in most cases. However, in spite of its low crystallinity, acetate fibers exhibited very low biodegradability, probably because of the presence of hydrophobic groups in its structure. On the other hand, linen showed an inconsistent behavior in that it had the highest biodegradability in the soil burial test, but a lower biodegradability than that of cotton in the activated sewage sludge test. XRD analysis revealed that there was a slight increase in the crystallinity of linen, cotton, and rayon fabrics at the initial stage, but a continuous decrease thereafter. From the correlation analysis, it was revealed that the biodegradability of cellulose fabrics was closely related to the moisture regain of the fibers, which reflects the hydrophilicity and internal structure of the fibers at the same time. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 248–253, 2004

Influence of Pretreatment on Physical Properties of Oxidized Rayon Fabrics

Strips of polynosic rayon cloth, pretreated with inorganic salts that act as catalysts in pyrolysis, are pyrolyzed in air by a continuous process to a desired temperature (250°C). TGA thermograms of selected samples are examined and reveal that inorganic salts alter the course of decomposition and form more residues. Variations in char yield, breaking strength, and filling shrinkage of charred rayon fabrics are examined, and the results indicate that the physical properties of charred fabrics are determined by the species and concentration of inorganic salts. Nevertheless, it is almost impossible for a single inor ganic salt to achieve all the desirable physical properties of charred fabrics. Therefore. there appears to be a potential for developing mixtures of inorganic salts to be applied in pretreatment to improve most of these properties. For instance, a rayon precursor impreg nated with a solution containing a mixture of NH4Cl (3% w/v) plus ZnCl2 (7% w/v) produces better results than one impregnated with single inorganic salts.

From Kitsch to Chic: The Transformation of Hawaiian Shirt Aesthetics

The Hawaiian shirt originated in the mid-1930s as a commodity for the tourist market. Unique elements in its design, including tropical print motifs in cartoon-like renditions, brilliant colors, and silky rayon fabrics made the shirt instantly recognizable and contributed to its status as both an essential souvenir purchase and the quintessential element in the stereotype of the tourist as sartorial nerd. An analysis of the transformation of the shirt - from tourist kitsch to highly valued collectible, and from collectible to global fashion - is framed on rubbish theory. The transformation is traced to an assortment of myths that reconstitute the souvenir commodity as an indigenous ethnic art form and a scarce relic of Hawai‘i’s romanticized past and to a surfeit of publications that position the shirt as a collector’s item. The merits of rubbish theory as a framework for the analysis are assessed, and apparel scholars are asked to consider the influence of myth and scholarship on changes in the aesthetic codes of other fashion and appearance-related commodities.

The Use of Atmospheric Pressure Plasma Treatment in Desizing PVA on Viscose Fabrics

In this study, both air-oxygen-helium and air-helium atmospheric pressure plasma treatments were employed to desize PVA on a rayon (viscose) fabric. Both the plasma treatments were able to remove some of the PVA on the rayon fabric and increase PVA solubility in cold water, resulting in a higher weight loss in cold washing. The effect of the atmospheric pressure plasmas became greater as the treatment time increased. Plasma treatment followed by one cold and one hot washing had the same effect as the conventional chemical treatments followed by two cycles of cold and hot washing. The atmospheric plasma treatment did not have negative effect on rayon fabric tensile strength.

Structural Analysis for Cellulose Fibers Treated by High Pressure Steam.

Morphology of high-pressure steamed cellulose fabrics were investigated using viscose rayon fabrics.Viscose rayon fabrics were steamed at several conditions without (dry-condition) and with (wet-condition) excess water.X-ray diffractometry revealed that the total crystallinity increased with generating cellulose Ⅳ.There were no dependences whether dry- or wet-steaming in their crystal forms.It is suggested that cellulose Ⅳ is generated from paracrystalline structure in the amorphous region.Further, steamed rayons were dyed by 5 kinds of reactive dyes to analyze the amorphous region.The relative color depths (K⁄S value) compared with the control were much decreased in dry-steamed viscose rayons whereas there was a slight difference in wet-steamed ones.The excess water at steaming showed a strong role to control the structure of the amorphous region.

Preparation of activated carbon cloth from viscous rayon: Part IV. Chemical activation

The chemical activation of viscous rayon fabric was carried out by impregnation with solutions of different chemicals (NH 4Cl, AlCl 3, ZnCl 2, CuCl 2, FeCl 3, H 3PO 4 or Na 2HPO 4), followed by carbonisation in an inert atmosphere. Impregnation modifies the pyrolysis of the precursor, favouring dehydration over depolymerisation, thus resulting in larger yield in respect to carbonisation of the unimpregnated fabric. The effect of each impregnant on yield, flexibility, strength and porosity of the resulting carbon cloth is analysed.

Flamability and Thermal Decomposition Behavior of Polylactide-Cellulose Union Cloths.

The flamability and the thermal decomposition behavior of polylactide-cellulose (cotton or rayon) union cloths were investigated. The limiting oxygen index (LOI) values of the union cloths were lower than that of 100% polylactide fabric, 24.1%. The LOI value of polylactide-cotton union cloth was 19.3%, or as the same level as that of 100% cotton fabric. The LOI value of polylactide-rayon union cloth was 19.3%, or 1.3% higher than that of 100% rayon fabric. The acceleration of the weight decrease of the polylactide-cotton union cloth was found in comparison with the estimated decrease based on the data of each component, polylactide and cotton according to the analysis by TG-DTA in air and nitrogen. On the other hand, the weight decrease of the polylactide-rayon union cloth was retarded on the initial stage, though it was accelerated after the middle of stage.

Preparation of activated carbon cloths from viscous rayon: Part III. Effect of carbonization on CO 2 activation

Viscous rayon cloth was carbonized under different experimental conditions The final temperature was 850°C, using heating rates of 0.5, 1, 3 and 5°C min −1; an additional char was obtained at 5°C min −1 but introducing an isothermal stage at 230°C a temperature near the pyrolytic decomposition of the precursor. A sixth char was prepared by treating the precursor in air at 230°C for 2.7 h before carbonization at 5°C min −1 up to 850°C. All chars were activated under a flow of carbon dioxide at 825°C. The effect of carbonization conditions on the porosity, mechanical strength and oxygen surface groups of resultant activated carbon cloth is analyzed, in order to optimize the properties of the final product.

Preparation of activated carbon cloths from viscous rayon. Part I. Carbonization procedures

Viscose rayon cloth was carbonized under a wide range of experimental conditions, including heating rate, isothermal stage near the temperature of decomposition, and preoxidation in air. Slower carbonization rates produce increases in yield, strength and micropore volume of the char, lower reactivity against gasification, and micropores with narrower entrances. The inclusion of an isothermal stage at temperatures near the beginning of the pyrolytic decomposition leads to a lower presence of constrictions in the char. Preoxidation with air produces an increase in carbonization yield and in breaking load; the presence of oxygen surface groups in the char are responsible for its higher reactivity to gasification.

Studies on changes in morphology during carbonization and activation of pretreated viscose rayon fabrics

Structural development during the carbonization and activation of pretreated viscose rayon fabrics in a carbon dioxide atmosphere at temperatures upto 900°C were followed using wide angle X-ray diffraction, elemental analysis and scanning electron microscopy (SEM) techniques. Porosity developments were also studied simultaneously. It is shown by X-ray results that the formation of turbostratic structure takes place at high temperature treatments (HTTS) of 900°C, which also coincides with the development of measurable porosity. Higher concentrations of inorganic chemicals in viscose rayon precursors are shown to affect the carbonization yield and porosity as well as the structure development. SEM results show that overactivation results in disintegration of the fabric structure.

Studies on the Function of Environmental Humidity Control of Textiles. (Part 3). Function of Environmental Humidity Control of Commodity Textiles.

The function of environmental humidity control (B-value) of Nylon6 fabric, Rayon fabric and Tencel fabric was evaluated as the representative of commodity textiles showing a moisture sorption-desorption. B-value of these textiles was depending on their moisture sorption: the nearly same value as Woolen fabric for Rayon fabric, the somewhat higher value than Cotton fabric for Tencel fabric and the considerably lower value than Cotton fabric for Nylon6 fabric were obtained at the specimen's weight of 0 to 20g/a volume of closed vessel (V=0.012m3). The change of moisture sorption in each textile during measurement of B-value was given as the difference between the moisture sorption isotherm at the side of lower temperature (25°C) and the moisture desorption isotherm at the side of higher temperature (35°C) . Based on this fact, the calculated relation curve of B-value and specimen's weight (g/V), using the moisture sorption isotherm at 25°C and the moisture desorption isotherm at 35°C, agreed well with the observed one.Furthermore, the B-values at 7.5g/V of a mixture composed of various fabrics including fabrics in previous paper [Sen'i Gakkaishi, 52, 234 (1996)], basically, was given as the average value with a mixed ratio of the B-value at 7.5g/V of its each component. Moreover, even if the relation curves of B-value and Wo/V between each component in a mixture was markedly different, it was given as the conversion B-value for a kind of component which was determined in this paper.

レーヨン繊維屑強化熱可塑性プラスチックの射出成形

レーヨン繊維屑強化熱可塑性プラスチックの射出成形

Effect of the Rubbing Fabric for Surface Liquid Crystal Alignment on Various Orientation Films

Abstract We have studied the effect of the rubbing fabric for pretilt angle generation, polar anchoring strength (energy), and the surface order parameter in nematic liquid crystals (NLC), 4-cyano-4′-n-penthylbiphenyl (5CB), on rubbed polyimide (PI) surfaces. The pretilt angle of 5CB for nylon and rayon fabric is larger than that of cotton fabric in weak rubbing on rubbed PI surfaces. The polar anchoring energy and surface order parameter of 5CB for nylon fabric are larger than those of cotton fabric on rubbed PI surfaces. We suggest that the polar anchoring energy and surface order parameter of 5CB increase with hard rubbing fabric. Finally, we conclude that the polar anchoring energy of 5CB is strongly related to the surface order parameter on rubbed PI surfaces.

Evaluation with B-value of the Function of Environmental Humidity Control of Textiles.

B-values of various moisture-absorbing textiles and usual interior materials such as lauan plywood were analyzed as a measure of the function of environmental humidity control, by measuring the continuous change of relative humidity accompaning with the periodic change of temperature in a closed vessel of 0.012 m3 including a textile or a usual interior material having a constant area or weight. The response of moisture-absorption (or-desorption) of each textile was quicker than that of lauan plywood for interior wall, so as to follow the change of relative humidity caused by the rapid change of temperature in a closed vessel. This is due to the markedly large specific surface area in a textile, concerning with the moisture-absorption (or-desorption), in comparison with that in a lauan plywood. The B-values determined at the constant area for each textile were lower than that of a lauan plywood, that is, the function of environmental humidity control of each textile was inferior to that of a lauan plywood. However, B-values at the constant weight for a cotton fabric, a woollen fabric, a rayon fabric and a solvron fabric were almost the same degree with that of lauan plywood. In B-values at the constant weight for these materials, the higher moisture-absorption led to the higher B-value. The highest moisture-absorption and the highest B-value were observed in the NF-38 non-woven fabric, 60 wt% of which was the high moisture-absorption fiber N-38. These results show that the function of environmental humidity control of materials, having a large and different specific surface area, should be evaluated by B-value at the constant weight and that the textiles having a superior function of environmental humidity control, exceeding that of lauan plywood, can be designed by controlling the weight/area of moisture-absorption textiles such as a cotton fabric.

Design of Effective Shrinking-Proof Modification of Cellulosics by Phosphoryl Amides

In the design of effective shrinking-proof modification of Cellulosics, the factors to be considered including cost, efficiency, durability of shrinking-proof, and effect of the treatment on the fabric properties. A number of finishing of rayon fabrics were performed by the use of crude phosphoryl amides prepared from the reaction of phosphoryl chloride with a saturated solution of ammonia in methanol (method A), from the reaction of ammonia with a solution of phosphoryl chloride (or chloro-phosphazene) in a solvent such as chlorinated alkanes or arenes, and ethers (method B).The most eminent characteristics in the use of the phosphoryl amides prepared by the method A were the more efficiently durable shrinking-proof and fastness against chlorine damage than the case of the method B. The increase in the amount of methoxy-substituted products at high temperatures in the method A caused the decrease in efficiency of shrinking-proof and whiteness of the treated rayon fabrics.Presence of water in methanol afforded hydroxy-substituted products and ammonium phosphate derivatives. However, the crude phosphoryl amides prepared in the presence of a small amount of water gave more desirable shrinking-proof, probably due to the catalytic effect of ammonium phosphate formed for the shrinking-proof. The optimum amount of water in the methanol was about 10%. Sodium borohydride treatment before the shrinking-proof increased the whiteness of the fabrics.

Correlation Between Wettability and Water Absorbency of Soiled Fabrics

The correlation between wetting properties and water absorbency was investigated for cellulosic and polyester fabrics soiled with various oily substances. As a measure of the wettability of oil, the work of adhesion between oil and water was estimated from surface and interfacial tension data. Water contact angles against the oily soiled cellophane and polyester films were measured to examine the wettability of the soiled surface. These wetting data were plotted against the water absorbency of the rayon and polyester fabrics soiled with oil. The results show good correlation between the wettability of oil or of the oily soiled surface and the liquid water uptake of the fabrics. However, the differences between the geometric structures of the fabrics and plain surfaces must be considered in further discussions.

Enzymatic Hydrolysis of Cotton, Linen, Ramie, and Viscose Rayon Fabrics

Cotton, linen, ramie, and viscose rayon fabrics along with a cotton / linen blend were hydrolyzed with cellulase from Trichoderma viride. Surface fibrils were eliminated by a 6 hour treatment in all cases. The loss of fibrillar matter appeared to be the primary cause of weight loss at this stage. On prolonged treatment, cotton, linen, and viscose rayon lost weight at a faster rate than ramie and the cotton / linen blend. The fall in yam strength was progressive with increasing weight loss for cotton and viscose, while for linen and ramie it was slight initially and then increased sharply. Retention of strength after 48 hours' incubation time increased in the order viscose rayon << cotton < ramie < linen, whereas weight loss increased in the order ramie < linen < cotton < viscose rayon. X-ray crystallinity and moisture sorption of the samples did not change after the treatment, indicating that the mechanism of endwise attack of the cellulase at accessiblc cellulose chains on crystallite surfaces appeared to apply to all four fibers. The location of enzymatic attack could be monitored with a light microscope using Congo red staining in the case of cotton and linen, but not ramie or rayon. Changes in surface morphology could be followed for all the enzyme-treated fibers by scanning electron microscopy. Additionally, mechanical tests demonstrated the changes in stretchability and stiffness of the fabrics and the mobility of yams within the samples.