Hasil untuk "Textile bleaching, dyeing, printing, etc."

Antje Ota, Marc Philip Vocht, Ronald Beyer et al.

Fiber demand of cellulosic fibers is rapidly increasing; however, these fibers are mainly based on the use of wood pulp (WP), which often have long transport times and, consequently, a high CO₂ footprint. So, alternative pulps based on non-wood, annual fast-growing plants are an option to cover the demand for raw materials and resources. Herein, we report on the use of a novel developed hemp pulp (HP) for man-made cellulosic fiber filament spinning. Commercial WP was used as a reference material. While HP could be used and directly spun as received without any further pretreatment, an additional step to adjust the degree of polymerization (DP) was needed to use the wood pulp. Continuous filaments were spun using a novel dry-jet wet spinning (HighPerCell^® process) technique, which is based on the use of 1-ethyl-3-methylimidazolium octanoate ([C₂C₁im][Oc]) as a solvent. Via this approach, several thousand meters (12,000 m–15,000 m) of continuous multifilament filaments were spun. The HP pulps showed excellent spinning performance. The novel approach allows the preparation of cellulosic fibers for either technical—with high tensile strength—or textile—possessing a low fibrillation tendency—applications. Textile hemp-based filaments were used for first weaving trials, resulting in a flawless fabric.

Yangxiao Yu, Guangzhou Song, Mengnan Dai et al.

Stent grafts play an important role in sealing vessel perforations, ruptures or aneurysms for remodeling vascular access, but maintaining long-term patency remains a major challenge after implantation. Silk fibroin (SF) is an ideal vascular graft material with excellent biocompatibility and physicochemical properties. In this study, we developed a series of composite grafts consisting of regenerated SF (RSF) and silk fabric, prepared using braiding technology and layer-by-layer (LBL) self-assembly, and investigated morphology, water permeability and cytotoxicity. The results showed that silk fabrics were covered effectively and tightly by RSF films, and the anti-water permeability of grafts was closely related to fabric structural parameters and self-assembly layers, in which the braiding angle of 90° and number of axial yarns above 60 threads/10 cm obtained very low water leakage. In particular, the graft prepared by 1 × 2 silk yarn had a thinner and more uniform thickness (70–80 μm), and showed lower water permeability (8.8 mL/min·cm2). Tests on L929 fibroblast cells showed that grafts had no significant cytotoxicity, and unreacted substances could be removed by LBL rinsing. These composite grafts may be promising biomaterials for the repair and regeneration of vascular access.

Kandula Ramanaiah, Srinivas Prasad Sanaka, A. V. Ratna Prasad et al.

Bio-composites were prepared by incorporating broom grass, fishtail palm, sansevieria fibers as reinforcement in unsaturated polyester resin using hand lay-up method. The thermo physical and fire properties of bio-composites has been examined by varying the fiber content (0 to 39 wt. %) and temperature (30–120°C). The thermal insulation and heat storage capability of samples was assessed using guarded heat flow meter and differential scanning calorimeter. The experimental results reveal that, as the weight fraction of fiber increased, the insulation capability of composites increased, whereas it decreased with the temperature. The response of specific heat and thermal diffusivity of composites with temperature was analyzed. Temperature distribution and heat transfer through the composite materials was computed using ANSYS fluent solver. The rate of heat transfer through the fishtail palm fiber composite is 14.02% lesser than glass fiber composite. Cone calorimeter was used to measure fire behavior of the samples and the results reveal that the broom grass fiber composite material possesses better fire resistance characteristics against fire hazard. Morphological study of composites was performed with the help of Scanning Electron Microscopy (SEM) for the visualization of homogeneity of surfaces. Developed bio-composites are the potential materials to replace petrochemical-based products.

Heebo Ha, Russ Thompson, Byungil Hwang

Achieving resistance to sedimentation of carbonyl iron powders (CIPs) in ethanol is important to fabricate reliable magnetorheological suspensions. The traditional method to improve the sedimentation stability is to add dispersants, but this approach can suffer from high costs and toxicity of added surfactants. In this study, the surface of CIPs was modified with 3-aminopropyl triethoxysilane (APTES) or tetraethyl orthosilicate (TEOS) to enhance the sedimentation stability of CIP suspensions without using toxic dispersants. After coating APTES or TEOS on the CIP surface, the surface energy of the CIP powders increased, which was attributed to the increased amino or hydroxyl groups on the CIP surface due to APTES or TEOS, respectively. The Gibbs free wetting enthalpy (ΔG) was calculated to evaluate the wettability of the modified CIPs, and APTES@CIPs or TEOS@CIPs had a low ΔG, indicating that both had a high thermodynamic spontaneity of wetting in ethanol. The enhanced wettability due to APTES or TEOS coating resulted in low CIP agglomeration, which resulted in APTES@CIPs or TEOS@CIPs dispersions having smaller average particle sizes than pure CIP dispersions. Therefore, APTES@CIPs or TEOS@CIPs showed more than 2 times slower sedimentation velocity than pure CIPs, resulting in enhanced sedimentation stability.

Yu Wang, Xuejiao Li, Junbo Xie et al.

The performance of fiber-reinforced composite materials is significantly influenced by the mechanical properties of the yarns. Predictive simulations of the mechanical response of yarns are, thus, necessary for fiber-reinforced composite materials. This paper developed a novel experiment equipment and approach to characterize the bending behavior of yarns, which was also analyzed by characterization parameters, bending load, bending stiffness, and realistic contact area. Inspired by the digital element approach, an improved modeling methodology with the probability distribution was employed to establish the geometry model of yarns and simulated bending behavior of yarns by defining the crimp strain of fibers in the yarn and the effective elastic modulus of yarns as random variables. The accuracy of the developed model was confirmed by the experimental approach. More bending behavior of yarns, including the twisted and plied yarns, was predicted by numerical simulation. Additionally, models revealed that twist level and number of plies affect yarn bending properties, which need to be adopted as sufficient conditions for the mechanical analysis of fiber-reinforced composite materials. This efficient experiment and modeling method is meaningful to be developed in further virtual weaving research.

Ruben Herberht Mamani-Cato, Eduardo Narciso Frank, Alejandro Prieto et al.

It is well known that objectionable fibres emerge from the surface of the yarn due to the centrifugal force of the spinning device. Furthermore, the hair removal process is based on the same physical principles. However, the fibres that are >30 µm (PcF) are the fibres that appear in the hairiness of the yarn and are eliminated by dehairing. It has always been presumed that the PcF was linearly correlated with the diameter of the fibre (MFD) in llamas, but not so in alpaca fibres. Nevertheless, there is evidence that this relationship is curvilinear and behaves the same way in both species. The objectives of this study are to explore the relationship between MFD and PcF in both llamas and alpacas, to explore the existence of a breaking point (BP) in this curvilinear relationship, and to determine the frequency of fleeces that do not require dehairing because the PcF ≤ 3.2%. In addition, the existence of a positive bias of coarse fibre content on the hairy surface (CFs) of the yarn to coarse fibre content within the yarn fibres (CFy) was determined, which may explain the effect of the dehairing on the prickle factor of SAC fibres. The relationship of PcF on MFD behaves the same way in alpacas and llamas. It conforms to a power distribution and presents a BP of 23 µm, with PcF being constant before the BP and increasing significantly after it. Most animals (≤91% of alpacas and ≤87% of llamas) are above the threshold (≤3.2%), requiring dehairing to correct it. By means of a shaving technique on the surface of the fabric sample, it was established that the objectionable CFs content is 8.15% higher than the objectionable CFy content. In the evoked-coarse fibre in the dehaired samples, a CFs-CFy difference below 5.9% (<i>p</i> > 0.05) is not significantly detected by panellists. The surface MFD is more than 2.7 µm coarser than the yarn MFD.

Qing Chen, Jie Feng, Bomou Ma et al.

Abstract Warp knitted mesh fabric was usually applied to sportswear due to good air transmission, but without multilayer structure and one-way transport property. In order to solve this problem, the miss-lapping structure was applied to examine the possibility to fabricate multilayer and improve water transport in warp knitting structure. Besides, the effect of thread type and warp density on comfort properties were also exploited to enhance the moisture management. The moisture management test, water vapor permeability and air permeability were examined. Long float at the back side in structure I formed by miss-lapping could improve liquid transport and air permeability, but slightly reduce water vapor permeability. With proper density, there existed the optimal one-way transport capacity and overall moisture management. Warp density in 20 cpc was an optimal parameter of knitting process. Taking advantage of miss-lapping, sample 5 where polypropylene was partly threaded on GB1 provided best moisture management, water vapor permeability and air permeability.

Pavan Hiremath, Sathyamangalam Ramanarayanan Viswamurthy, Manjunath Shettar et al.

Aircraft structures must be capable of performing their function throughout their design life while meeting safety objectives. Such structures may contain defects and/or damages that can occur for several reasons. Therefore, aircraft structures are inspected regularly and repaired if necessary. The concept of combining an inspection plan with knowledge of damage threats, damage growth rates, and residual strength is referred to as “damage-tolerant design” in the field of aircraft design. In the present study, we fabricated a composite panel with a cutout (which is generally found in the bottom skin of the wing) using a resin infusion process and studied the damage tolerance of a co-cured skin-stringer composite panel. The composite panel was subjected to low-velocity impact damage, and the extent of damage was studied based on non-destructive inspection techniques such as ultrasonic inspection. Fixtures were designed and fabricated to load the composite panel under static and fatigue loads. Finally, the panel was tested under tensile and fatigue loads (mini TWIST). Deformations and strains obtained from FE simulations were compared and verified against test data. Results show that the impact damages considered in this study did not alter the load path in the composite panel. Damage did not occur under the application of one block (10% life) of spectrum fatigue loads. The damage tolerance of the stiffened skin composite panel was demonstrated through test and analysis.

S. O. Bamaga

Currently, natural fibers attract the attention of researchers and builders in the construction industry as they are eco-friendly, cost-effective, lightweight, and renewable resources. The inclusion of natural fibers in the concrete and mortar will contribute to solving the environmental problems associated with dumping or burning them and improve the properties and durability of concrete and mortar. Similar to other natural fibers, Date Palm Fibers (DPF) have been receiving more attention as construction materials. This paper presents a review on the properties of DPF and its effects on the physical, mechanical, and thermal properties of concrete and mortar as well as the processing of DPF and mix design. DPFs can be used in concrete and mortar to improve their properties. However, some of the properties could be reduced. Even though the conducted studies and investigations are promising, it is still not enough to introduce DPF concrete and mortar to the construction industry’s applications.

Linlin Li, Yanbing Zhu, Yan Song et al.

Rabbit hair is an excellent textile fiber owing to its softness and luster. However, the poor spinnability of rabbit hair restricts its application on textiles. In this article, ionic liquid (IL) solutions were used to treat rabbit hair at five different temperatures. The raw and treated rabbit hair was then characterized by microscope, scanning electron microscope (SEM), mechanical property, XRD, and properties related to spininability (crimp and friction property, moisture regain, and electrical performance). The results showed that the rabbit hair fiber’s morphology was obviously curled, and mechanical properties and crystallinity were reduced after ILs treatment. Moreover, the friction performance was increased by 15% and the crimp rate was increased by 7.2 times. These results suggest that with proper temperatures of ILs treatment, the rabbit hair could show better potential for spinning.

Carlos Tenazoa, Holmer Savastano, Samuel Charca et al.

Ichu and Cabuya were characterized and the effect of alkali treatment on the chemical and physical properties of these fibers was studied. This treatment was carried out to remove non-cellulosic components in order to improve the adhesion of these fibers to be used as reinforcing composites since they are currently being tested in polymer matrix composites. The chemical properties were investigated through TAPPI Standards and FTIR spectroscopy. The physical properties (microfibrillar angle and density) were analyzed through polarized light microscopy and a gas pycnometer, respectively. The results show that with this chemical treatment, it is possible to remove 53.9% of lignin and 22.7% of hemicellulose for Ichu fiber and 50.7% and 91.7%, respectively, for Cabuya. Besides, it was found that the microfibrillar angle is not affected by this chemical treatment since its effect is only superficial. In addition, SEM images show that Ichu fiber has amorphous silica particles in its surface, in which it becomes a potential fiber for cement composites.

Jyoti Jain, Shishir Sinha, Shorab Jain

Nowadays, the research is more focused on natural fibers because of their comparable properties of biodegradability, environment friendly, ease of access, lightweight, and low cost. In this research paper, the effect of chemical treatment on morphological, physical, chemical, mechanical, and thermal properties of pineapple leaf fibers has been studied. Because of the highest amount of cellulosic content, this fiber is having great potential for mechanical and thermal strength. Initially, fibers were extracted using retting and scrapping method and thereafter treatment with different concentrations of alkali was performed. Characterization has been done to analyze its properties and found that the alkaline treatment leads to better mechanical and thermal properties but only up to 7% alkali concentration. After increasing the concentration above 7%, the properties start degrading because of the onset of fiber degradation at higher alkali application. Mercerization helps in making fiber more compatible with hydrophobic matrix resin and hence can be easily reinforced with polymeric matrix for specific composite applications.

Wilgocka Karolina, Skrzetuska Ewa, Krucińska Izabella et al.

Premature birth is considered to be a substantial problem in perinatal medicine, which in the vast majority of cases (>60%), concerns African and South Asian countries. Nevertheless, prematurity is a global problem and is faced by both less-developed (where 12% of babies are prematurely born) and well-developed countries (with 9% prematurity rate) [1, 2]. The percentage of children born prematurely, i.e., before the 37th week of pregnancy, was 8.7% in Europe, while, in Poland, it was 7.34% [3]. Care of prematurely born babies is a huge challenge for parents and medical staff in the neonatal intensive care unit. Preterm infants, because of their low weight and gestational age, are prone to health problems and even death. For this reason, continuous monitoring of health parameters plays an important role. It is achieved by the use of various sensors that are inserted in infants’ garments. Sensor systems monitor an infant’s health condition, and then the data are transmitted to doctors or parents. This article is for illustrative purposes, aimed at presenting solutions such as the use of sensors for monitoring infants’ physiological parameters.

Jean Ivars, Ahmad Rashed Labanieh, Damien Soulat

Recycling carbon-fibre-reinforced plastic (CFRP) and recovering high-cost carbon fibre (CF) is a preoccupation of scientific and industrial committees due to the environmental and economic concerns. A commercialised nonwoven mat, made of recycled carbon fibre and manufactured using carding and needle-punching technology, can promote second-life opportunities for carbon fibre. This paper aims to evaluate the mechanical and preforming behaviour of this nonwoven material. We focus on the influence that the fibre orientation distribution in the nonwoven material has on its mechanical and preforming behaviour at the preform scale, as well as the tensile properties at composite scale. The anisotropy index induced by fibre orientation is evaluated by analysing SEM micrographs using the fast Fourier transform (FFT) method. Then, the anisotropy in the tensile, bending, and preforming behaviour of the preform is inspected, as well as in the tensile behaviour of the composite. Additionally, we evaluate the impact of the stacking order of multi-layers of the nonwoven material, associated with its preferred fibre orientation (nonwoven anisotropy), on its compaction behaviour. The nonwoven anisotropy, in terms of fibre orientation, induces a strong effect on the preform mechanical and preforming behaviour, as well as the tensile behaviour of the composite. The tensile behaviour of the nonwoven material is governed by the inter-fibre cohesion, which depends on the fibre orientation. The low inter-fibre cohesion, which characterises this nonwoven material, leads to poor resistance to tearing. This type of defect rapidly occurs during preforming, even at too-low membrane tension. Otherwise, the increase in nonwoven layer numbers leads to a decrease in the impact of the nonwoven anisotropy behaviour under compaction load.

Parag Bhavsar, Tudor Balan, Giulia Dalla Fontana et al.

In the EU, sheep bred for dairy and meat purposes are of low quality, their economic value is not even enough to cover shearing costs, and their wool is generally seen as a useless by-product of sheep farming, resulting in large illegal disposal or landfilling. In order to minimize environmental and health-related problems considering elemental compositions of discarded materials such as waste wool, there is a need to recycle and reuse waste materials to develop sustainable innovative technologies and transformation processes to achieve sustainable manufacturing. This study aims to examine the application of waste wool in biocomposite production with the help of a sustainable hydrolysis process without any chemicals and binding material. The impact of superheated water hydrolysis and mixing hydrolyzed wool fibers with kraft pulp on the performance of biocomposite was investigated and characterized using SEM, FTIR, tensile strength, DSC, TGA, and soil burial testing in comparison with 100% kraft pulp biocomposite. The superheated water hydrolysis process increases the hydrophilicity and homogeneity and contributes to increasing the speed of biodegradation. The biocomposite is entirely self-supporting, provides primary nutrients for soil nourishment, and is observed to be completely biodegradable when buried in the soil within 90 days. Among temperatures tested for superheated water hydrolysis of raw wool, 150 °C seems to be the most appropriate for the biocomposite preparation regarding physicochemical properties of wool and suitability for wool mixing with cellulose. The combination of a sustainable hydrolysis process and the use of waste wool in manufacturing an eco-friendly, biodegradable paper/biocomposite will open new potential opportunities for the utilization of waste wool in agricultural and packaging applications and minimize environmental impact.

Yu Wang, Shijie Chai, Mingjie Xin et al.

Cold atoms trapped and guided in hollow-core photonic crystal fibers provide a scalable diffraction-free setting for atom–light interactions for quantum technologies. However, due to the mismatch of the depth and spatial extension of the trapping potential from free space to the fiber, the number of cold atoms in the fiber is mainly determined by the loading process from free space to waveguide confinement. Here, we provide a numerical study of the loading dynamics of cold atoms into a hollow-core photonic crystal fiber. We use the Monte Carlo method to simulate the trajectories of an ensemble of cold atoms from free space trapping potential to optical potential inside a hollow-core fiber and calculate the temperature, loading efficiency, and geometry of the ensemble. We also study the noise sources that cause heating and a loss of atoms during the process. Our result could be used to design and optimize the loading process of cold atoms into a hollow-core fiber for cold atom experiments.

Ekrem Gulsevincler, Mustafa Resit Usal, Demet Yilmaz

In this study, the effect of 100% atmospheric relative humidity on yarn properties was investigated using jet-ring nozzles and compared with the yarn properties of yarns produced with air operated jet-ring nozzles under normal conditions. As a humidification system, a pneumatic conditioner, also known as a lubricant, was used in pneumatic systems. This conditioner was connected just before the pneumatic distributor that supplies air to the nozzles. The tube in stage 2 of the conditioner was filled with pure water at room temperature (25 °C ± 2 °C). The air conditioner dose was adjusted to 100% atmospheric relative humidity. The use of humidified air to jet-ring nozzles had a slight positive effect on all yarn properties (yarn hairiness, yarn irregularity, yarn elongation and yarn tenacity). According to the results, it resulted in a 1% to 3% improvement in yarn quality. This study is the first example and an original study in this field, as there is no study using humidified air in existing jet-ring air nozzle studies. It was proven in this study that humidified air results in a slight improvement in yarn properties.

Klara Kostajnšek, Krste Dimitrovski

Apart from their soft feel and good water absorbency, cotton fabrics are also characterised by good heat conductivity, air permeability and breathing. By increasing the open surface of one-layer fabrics, their air and water vapour permeability, and heat conductivity should increase as well, whereas the protection against UV rays, on the other hand, which is especially important for summer clothes, decreases. The aim of the research was to establish the influence of multilayer cotton fabric constructions on the properties connected with porosity, i.e. thermal resistance, water vapour resistance, UV-light permeability and air permeability. One-layer, two-weft and double cotton fabric constructions were woven from white, blue and black yarn with fineness 8 × 2 tex, warp density 40 ends/cm and weft density 60 picks/cm, taking into consideration the colour distribution of yarns in the fabrics as well. The research results showed that the most optimal construction characterises multilayer two-weft and double fabrics. Among the studied fabrics, a positive correlation was established between the porosity of fabrics and their air permeability or ultraviolet protection factor (UPF), respectively, and a negative correlation between the porosity of fabrics and their heat or water vapour permeability, respectively. The correlation between the calculated number of pores of individual samples, as an important factor in porosity, and the studied permeability resistance properties (i.e. heat resistance, water vapour resistance, UV-light permeability and air permeability resistance) was higher than the correlation between the porosity of samples and the abovementioned permeability properties.

Zhu Bo, Liu Jianli, Gao Weidong

This study was aimed at investigating the process optimization of foam sizing for cotton yarns. In this work, effects of major foam-sizing process factors including size concentration, blowing ratio, stirring speed, pre-wetting temperature, pre-drying temperature, squeezing pressure and drying temperature were studied on the hairiness (more than 3 mm) and abrasion resistance of foam-sized yarns. The combination of Plackett-Burman, steepest ascent path analysis and Box-Behnken design were adopted to optimize the foam-sizing process of cotton yarns. Results revealed that size concentration, blowing ratio and squeezing pressure were significant factors that affected the hairiness and abrasion resistance. Optimum hairiness and abrasion resistance were obtained when the cotton yarns were sized at size concentration of 19.33%, blowing ratio of 4.27 and squeezing pressure of 0.78kN. The theoretical values and the observed values were in reasonably good agreement and the deviation was less than 1%. Verifcation and repeated trial results showed that it has good reproducibility and imparts the foam sizing process of cotton yarns.

Gea Guerriero, Lauralie Mangeot-Peter, Jean-Francois Hausman et al.

In plants there is no universal protocol for RNA extraction, since optimizations are required depending on the species, tissues and developmental stages. Some plants/tissues are rich in secondary metabolites or synthesize thick cell walls, which hinder an efficient RNA extraction. One such example is bast fibres, long extraxylary cells characterized by a thick cellulosic cell wall. Given the economic importance of bast fibres, which are used in the textile sector, as well as in biocomposites as green substitutes of glass fibres, it is desirable to better understand their development from a molecular point of view. This knowledge favours the development of biotechnological strategies aimed at improving specific properties of bast fibres. To be able to perform high-throughput analyses, such as, for instance, transcriptomics of bast fibres, RNA extraction is a crucial and limiting step. We here detail a protocol enabling the rapid extraction of high quality RNA from the bast fibres of textile hemp, Cannabis sativa L., a multi-purpose fibre crop standing in the spotlight of research.