Rayon Fibers Research Articles

Liquid handling properties of hollow viscose rayon/super absorbent fibers nonwovens for reusable incontinence products

To develop reusable incontinence products, blend nonwovens of hollow viscose rayon (HVR) and super absorbent fibers (SAFs) were prepared using a needle-punching process and their liquid handling properties, such as the fluid absorption capacity, fluid retention capacity, fluid absorption under load, moisture evaporation rate, and repeated water absorption were investigated. As the SAF content in the HVR/SAF blend nonwovens was increased, the fluid absorption capacity, fluid retention capacity, and fluid absorption under load increased, whereas the moisture evaporation rate decreased. SAF had a more significant effect on fluid retention than fluid absorption. In the case of HVR/SAF(8/2) and HVR/SAF(7/3), more than 100 % of the fluid absorption capacity was retained even after 5 cycles of repeated water absorption tests. Overall, the HVR/SAF blend nonwovens are good candidates for reusable incontinence products.

Self-Decontaminating Fibrous Materials Reactive toward Chemical Threats.

Polymers that possess highly nucleophilic pyrrolidinopyridine (Pyr) and primary amino (vinylamine, VAm) groups were prepared by free-radical copolymerization of N,N-diallylpyridin-4-amine (DAAP) and N-vinylformamide (NVF) followed by acidic hydrolysis of NVF into VAm. The resulting poly(DAAP-co-VAm-co-NVF) copolymers were water-soluble and reacted with water-dispersible polyurethane possessing a high content of unreacted isocyanate groups. Spray-coating of the nylon-cotton (NYCO), rayon, and poly(p-phenylene terephthalamide) (Kevlar 119) fibers pretreated with phosphoric acid resulted in covalent bonding of the polyurethane with the hydroxyl groups on the fiber surface. A second spray-coating of aqueous solutions of poly(DAAP-co-VAm-co-NVF) on the polyurethane-coated fiber enabled formation of urea linkages between unreacted isocyanate groups of the polyurethane layer and the amino groups of poly(DAAP-co-VAm-co-NVF). Fibers with poly(DAAP-co-VAm-co-NVF) attached were compared with fibers modified by adsorption of water-insoluble poly(butadiene-co-pyrrolidinopyridine) (polyBPP) in terms of the stability against polymer leaching in aqueous washing applications. While the fibers modified by attachment of poly(DAAP-co-VAm-co-NVF) exhibited negligible polymer leaching, over 65% of adsorbed polyBPP detached and leached from the fibers within 7 days. Rayon fibers modified by poly(DAAP-co-VAm-co-NVF) were tested for sorption of dimethyl methylphosphonate (DMMP) in the presence of moisture using dynamic vapor sorption technique. Capability of the fibers modified with poly(DAAP-co-VAm-co-NVF) to facilitate hydrolysis of the sorbed DMMP in the presence of moisture was uncovered. The self-decontaminating property of the modified fibers against chemical threats was tested using a CWA simulant diisopropylfluorophosphate (DFP) in aqueous media at pH 8.7. Fibers modified with poly(DAAP-co-VAm-co-NVF) facilitated hydrolysis of DFP with the half-lives up to an order of magnitude shorter than that of the unmodified fibers. The presented polymers and method of multilayer coating can lead to a development of self-decontaminating textiles and other materials.

Effects of octamaleamic acid-POSS used as the adhesion enhancer on the properties of silicone rubber/silica nanocomposites

Abstract In this paper, the addition of octamaleamic acid-POSS (OM-POSS) nanoparticles to silicone rubber (SR) composites were investigated for enhancing the adhesion properties to reinforcing fibers. The content of OM-POSS was examined as the experimental parameter. The reference was a 5-phr silica filled SR compound. The peroxide curing characteristics of composites was determined by means of differential scanning calorimeter (DSC) and moving die rheometer. It was found that OM-POSS retarded the curing time and decreased the crosslinking density. DSC analysis indicated that the crosslinking reaction started at lower temperature as the OM-POSS concentration increased. The dynamical mechanical analysis (DMA) results showed that the melting point decreased by the addition of OM-POSS content. The crystallinity of SR decreased with increasing OM-POSS content. The thermal stability of SR composites obtained from TGA apparently improved by the addition of OM-POSS. The SEM and TEM pictures showed that the OM-POSS distribution was homogeneous at lower contents, but some agglomerates were seen when the content of OM-POSS increased. Tensile tests exhibited that comparable mechanical properties were achieved for SR/OM-POSS composites with respect to reference composite. It was demonstrated by H-adhesion tests that the utilization of OM-POSS in the SR composites improved the adhesion of the matrix to Rayon fiber.

Synthesis, Characterization and Application of Nano Cellulose for Enhanced Performance of Textiles

In the present investigation cellulose nano whisker is separated from industrial waste viscose rayon fibre, characterized by SEM images and FTIR spectroscopy. The size and size distribution of these nano crystals have also been examined using particle size analyzer; the average size of the particles is found to be 348 nm. The findings support the size and shape of the synthesized nano cellulose particles. These nanoparticles have been applied to polyester fabric by padding technique and manifested the improved physical and thermal properties. The dyeing behaviour of the treated fabrics with direct dye has also been studied and the build-up of dyes, measured as colour strength in terms of K/S values, reported. The higher K/S values are obtained when the cellulose nano is anchored in the fibre matrix, i.e. when the fibre is pre-treated and dyed with direct dyes. Improved colour strength with good resistance towards soaping is obtained after treatment of fabrics with nano cellulose.

A comparative study of magnetic resonance imaging, electrical impedance tomography and ultrasonic doppler velocimetry for semi-dilute fibre flow suspension characterisation

Experimental comparisons between imaging techniques serve to provide confidence in the validity of each technique for the study of multiphase flow systems. Such cross-validation can establish the limitations of each technique quantitatively. In the present paper, the authors report efforts made on the characterization of semi-dilute, mono-dispersed suspensions of rayon fibres in turbulent water flow using Magnetic Resonance Imaging (MRI), Ultrasound Velocity Profiling (UVP) and Electrical Impedance Tomography (EIT). Increasing flow velocities and fibre concentration were studied using these three experimental techniques. For lower fibre concentrations more uniform distributions were observed and as flow velocity increased fibre agglomerations were found in the centre region of the pipe.

Microplastics in coastal sediments from Southern Portuguese shelf waters

Microplastics are well-documented pollutants in the marine environment that result from fragmentation of larger plastic items. Due to their long chemical chains, they can remain in the environment for long periods of time. It is estimated that the vast majority (80%) of marine litter derives from land sources and that 70% will sink and remain at the bottom of the ocean. Microplastics that result from fragmentation of larger pieces of plastic are common to be found in beaches and in the water surface. The most common microplastics are pellets, fragments and fibres.This work provides original data of the presence of microplastics in coastal sediments from Southern Portuguese shelf waters, reporting on microplastic concentration and polymer types.Microplastic particles were found in nearly 56% of sediment samples, accounting a total of 31 particles in 27 samples. The vast majority were microfibers (25), identified as rayon fibres, and fragments (6) identified as polypropylene, through infrared spectroscopy (μ-FTIR). The concentration and polymer type data is consistent with other relevant studies and reports worldwide.

Solvent infusion processing of all-cellulose composite laminates using an aqueous NaOH/urea solvent system

All-cellulose composites are high performing green materials and solvent infusion processing makes their upscaled manufacturing possible. This study explored the use of aqueous 7wt.% NaOH/12wt.% urea solution as cost effective and environmentally friendly cellulose solvent for solvent infusion processing. A short dissolution time of 5min led to all-cellulose composite laminates with a tensile strength of 114±1.9MPa and a Young’s modulus of 7.8±0.5GPa. A decrease of tensile strength and Young’s modulus with increasing dissolution time from 5 to 60min was linked to changes in composite microstructure and fine structure of the reinforcing rayon fibres. It was shown that aqueous NaOH/urea solution is a promising alternative solvent, as it offers the advantages of shorter processing times and reduced solvent costs by 97%, while resulting in 25% stronger laminates, when compared to using ionic liquids.

Effect of (NH4)2SO4 Concentration on the Pyrolysis Properties of Rayon Fiber from Bamboo

(NH4)2SO4 solution was employed to pre-treat regenerated cellulose fiber (from bamboo) using an ultrasonic method, and then the material was heat-treated at 250 °C. Scanning electron microscopy revealed that erosion and cracks of the fiber surface increased after being impregnated with (NH4)2SO4 combined with ultrasonic pretreatment. There was a small change in the intensity and the position of some peaks in the Fourier transform infrared spectra, and in the heat treatment, partial pyrolysis of the cellulose occurred. The data showed that for the cellulose fiber pretreated with 5 wt% (NH4)2SO4 the decomposition temperature shifted to the lower side (252 °C), and the decomposition range (180 °C to 454 °C) was wider than for the other impregnation fibers and reference. However, the rate of decomposition was different with different concentrations of (NH4)2SO4. The C content of heat-treated fiber with 5 wt% (NH4)2SO4 increased to 52%. The above results indicated that the (NH4)2SO4 was an effective catalyst to pretreat regenerated cellulose fiber in the pathway of pyrolysis.

Utilizing Rayon Fiber Residues from Fiber Manufacturing Industry for Preparation of Cellulose/CMC Hydrogels

The cellulose-based hydrogel was successfully prepared from rayon fiber residue obtained from the fiber manufacturing industry. By chemical means, the hydrogel was simply prepared at an ambient temperature by mixing rayon with carboxymethyl cellulose (CMC) in NaOH/urea solution with epichlorohydrin (ECH) as a crosslinking agent. Rayon cellulose was used for stabilizing of hydrogel structure, providing a dimensional stability to the hydrogel whereas CMC acted as a porogen, widening the pore size within the hydrogel structure while swelling in water. With increasing CMC content, the percent water uptake of the hydrogel was increased but the structural stability was impaired. The prepared rayon cellulose/CMC hydrogel could take up more than 200% water within 60 minutes with an appropriate rayon cellulose-to-CMC ratio of 1:1 providing an ultimate balance between percent water uptake and the structural stability of the hydrogel. Its percent water uptake was as high as 285% to its initial dry weight.

A three-dimensional model of fine particle retention during percolation through a fiber mat

Fine particles are usually retained in fiber mats by sieving. To date, no theory has combined fiber and mat characteristics into a predictive retention model. A multilayer analytical retention model developed during this study predicts retention within a thick fiber mat by modeling retention as particles pass through a series of very thin fiber mats. A suspension of 5-75 μm toner particles was percolated through rayon fiber mats. The model’s prediction approached the experimental data only when the ratio of particle diameter to fiber diameter increased toward 2.0, the upper limit within the rayon fiber mat data set. Retention was also experimentally determined on the macroscale with simulated fiber mats, through which 4-20 mm beads were dropped. The particle diameter was at least 2.2 times the fiber diameter for all of the macroscale experimental data, explaining the much better fit of the data from those experiments to the model’s predictions.

Study of Weathering Resistance of Textile Materials in Outdoor Rack Testing. Effect of Climate Zone

We have established the effect of basic meteorological weathering factors in two climate zones in Russia (St. Petersburg, Kursk) on the kinetics of the change in breaking strength of textile materials during their exposure to weathering. The most rapid degradation was found for the Kursk zone. The rate of degradation depends to the greatest extent on the activity of the total (direct plus diffuse) solar radiation in the studied climate zones. In order to predict degradation, we present monthly and yearly values of the total solar radiation for a number of cities in Russia, allowing us to determine the most active zones for weathering degradation. Based on the values of the insolation index, we rank the weathering resistance of materials made from wool, polyester, cotton fibres and polyester/wool, flax/ polyester, and cotton/polyester blends. We evaluate the resistance of polyamide, SVM, rusar, Fenilon, arimid, polypropylene, natural silk, viscose rayon, silica, Kermel, and Twaron fibres. The insolation index of the studied materials ranged from 4 to 70 units.

Effect of compressibility of synthetic fibers as conditioning materials on dewatering of activated sludge

Efficient solid–liquid phase separation of excess sludge from the mixed-liquor suspended solids in wastewater treatment is difficult to achieve without prior sludge conditioning. Several physical conditioners have been assessed as skeleton builders or filtering aids to reduce sludge compressibility; however, little is known about how the properties of the physical conditioner affect sludge compressibility and dewaterability. In this study, synthetic poly(ethylene terephthalate) (PET), polypropylene, and viscose rayon (VR) fibers were used as physical conditioners for activated sludge, and the effects of the fiber compressibility on the dewaterability of activated sludge collected from a laboratory-scale reactor were assessed. Based on expression experiments using a laboratory-scale apparatus, it was found that: (1) the rate of consolidation of sludge cakes increased after incorporation of synthetic fibers, particularly at the primary stage. (2) The porosity of the sludge cake was maintained only with fibers that required high pressures for compaction (i.e., PET and VR); thus, high dewaterability of the cakes was achieved with these fibers. It is proposed that the compressibility of the physical conditioner may be one of the more important factors for improving sludge dewaterability.

Function of rayon fibers with metallophthalocyanine derivatives: potential of low-molecular weight polycyclic aromatic hydrocarbon removal and Bacillus sp. removal.

Polycyclic aromatic hydrocarbons (PAHs) are known as carcinogenic and/or mutagenic substances, and are present at high concentration in polluted environments. It has recently been reported that spore-forming bacteria (e.g., Bacillus spp.) can be transported long distances alive in the atmosphere, which raises the possibility that some of the transported bacteria could have adverse effects on human health. There is thus a need for filters that can remove gaseous PAHs from the air that people breathe and that can inhibit bacterial growth on the filters. We focused on metallophthalocyanine derivatives (M-Pc) which are known to adsorb PAHs as well as to inhibit the growth of bacteria as a potential filtering agent. In this study, we developed different types of M-Pc-supported rayon fibers by changing central metals, functional groups, concentrations of M-Pc and rayon types, and evaluated their removal effects by measuring adsorption rates of 3- and 4-ring PAHs with a HPLC and growth curves of Bacillus sp. with a spectrophotometer. The results showed that both the effects depended on functional groups and concentrations of M-Pc, and rayon types. The most effective combination was observed in Fe-Pc with sulfo group supported on cationized rayon fiber at the concentration of 2 to 3.3 wt%. Central metal species of M-Pc were influenced only on the antibacterial properties. This fiber would be applicable to filtering agents and textiles.

Bamboo as Raw Materials for Dissolving Pulp with Environmental Friendly Technology for Rayon Fiber

Dissolving pulp raw material for rayon in Indonesia is wood. The limited availability of wood, nonwood is available in large numbers such as bamboo. Bamboo fibre has long fibre. A study for making of dissolving pulp of four types of bamboo such as Apus (Gigantochloa apus), Petung (Dendrocalamus asper), Mayan (Gigantochloa robusta) and Sembilang (Dendrocalamus giganteus). The pulping process is Pre-hydrolysed-Kraft and bleaching of pulp with environmental friendly technology (Elemental Chlorine Free and enzyme). Pulp bleaching yield between 94-97% is still high. Cellulose content bamboo dissolving pulp is higher than requirements Indonesian standard specification SNI (> 94%).

Preparation of Cuprammonium Biodegradable Rayon Fibers from Different Papers with Schweitzers Solution.

Preparation of Cuprammonium Biodegradable Rayon Fibers from Different Papers with Schweitzers Solution.

Property Analysis of Stainless Steel Fiber (Yarn) and its Effect on Knitting Process

In this paper the frictional and tensile properties of stainless-steel fiber, cotton fiber, polyester fiber and rayon fiber, as well as the tensile and surface hairy properties of stainless-steel yarn, cotton yarn and wool yarn were tested and compared. Experimental results shown that the stainless-steel fiber has greater density, friction coefficient and tensile breakage strength but smaller breaking elongation. On the basis of summarizing the differences between stainless-steel fiber (yarn) and conventional textile fibers (yarns), difficulties occurred during knitting process were analyzed and the corresponding solutions were proposed.

활성탄소섬유 제조시 전처리된 레이온 섬유의 열특성 분석

활성탄소섬유 제조시 전처리된 레이온 섬유의 열특성 분석

Carbonization behavior of oxidized viscose rayon fibers in the presence of boric acid–phosphoric acid impregnation

The oxidation and carbonization stages of viscose rayon fibers were performed in the presence of 3 % phosphoric acid and 4 % boric acid (PA–BA) impregnation. The results showed that PA–BA impregnation enhanced thermal stability and prevented the evolution of volatile by-products. During the oxidation stage carried out at 250 °C, the cellulose II crystalline structure was totally lost due to the decrystallization process. Carbonization was carried out in a pure nitrogen atmosphere at temperatures ranging from 600 to 1000 °C. The results obtained from the fiber thickness, linear density, carbon fiber yield, elemental analysis, volume density, X-ray diffraction, infrared (IR) and Raman spectroscopy, tensile testing, and electrical conductivity measurements showed that the carbonization temperature had a significant effect on the structure and properties of the resulting carbon fibers. Carbon fibers obtained from the oxidized viscose rayon fibers showed physical and chemical transformations with increasing carbonization temperature and were characterized by a reduction in fiber thickness and linear density values due to the removal of non-carbon elements together with increases in the carbon content, carbon to hydrogen ratio (C/H), volume density, tensile strength, tensile modulus, and electrical conductivity values. X-ray diffraction analysis showed that the interplanar d-spacing (d002) decreased, and that the apparent crystallite thickness (Lc) and the apparent crystallite width (La) increased with increasing temperature. IR spectroscopy in agreement with the elemental analysis showed the total loss of OH, CH, C=O, CH2, C–O, and C–O–C groups arising from the completion of dehydration and dehydrogenation reactions indicating total elimination of the cellulose structure and the formation of amorphous carbon during high temperature treatment.

Sorption of Flame Retardant by Viscose Rayon Fiber in Manufacture of Flame-Resistant Fibers

Based on analysis of the effect of modification parameters (bath liquor ratio, temperature, modifier concentration) on the physicomechanical and physicochemical properties of viscose rayon fibers, and also application of mathematical modeling to determine the equilibrium adsorption and the rate at which adsorption equilibrium is established when the fiber is soaked in an aqueous solution of flame retardant, we have determined the optimal modification parameters ensuring that a fire-resistant viscose rayon fiber is obtained while preserving its physicomechanical characteristics.

Three-dimensional braiding of continuous regenerated cellulose fibres

A growing interest in biocomposites leads to the extension of commonly used three-dimensional braiding processes for composite preforming to cellulose-based fibres. A rayon fibre (Cordenka™) is processed on an Institut für Textiltechnik 3D rotary braiding machine, generally used for the processing of stronger and stiffer glass and carbon fibres. A rectangular profile was produced from 32 yarns and the braiding angle of the yarn was analysed. Analysis of the fibre tensile properties during the different processing steps revealed only a minor reduction in fibre strain. The fibre strength and Young’s modulus were unaffected by the braiding process showing that 3D rotary braiding can be extended to biobased fibres without any required changes.