首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献，搜索用时 31 毫秒
1.
Nowadays, the use of nonwovens as absorbent products is increasing. One of the most important methods for the nonwoven production is spunlace. This research evaluates the effect of spunlace nonwoven structures in wicking, water retention, water vapor permeability and porosity structural parameter of nonwoven. Carded webs from polyester fibers and viscous fibers of four different basis weights (35, 40, 45, and 50 g/m2) were hydroentangled using three different water jet pressures (50, 60, and 70 bar). To study the effect of these variables on the structure of nonwovens and absorbency related properties, sample’s characteristics such as thickness and mass density were measured. An electrical resistance technique was used to study the liquid penetration into nonwovens. The results showed that with increasing water jet pressure, mass density increased and other parameters like thickness, water retention, water vapor permeability and capillary pore size decreased. Also, it was observed with increasing basis weight, the sample thickness increased. On the other hand, with increasing weight, the amount of water retention, water vapor permeability and porosity structural parameter of nonwoven were reduced. The wicking characteristic of nonwovens using the least jet pressure and weight was the best of all the samples.  相似文献   

2.
The fibrous porous materials stand out as a unique class of porous media. The air permeability of these media is very important for a wide variety of medical and technical applications. It is observed that the air permeability of these media is different at different locations owing to the nonuniformity in fibre packing density. This observation is taken into consideration while developing an analytical model of air permeability of nonuniform fibrous porous media. This model is reported in this article and demonstrated with the help of practical examples of real nonwoven fibrous porous materials. The theoretical results are found to be in satisfactory agreement with the experimental ones.  相似文献   

3.
For their functional enhancement, sanitary nonwoven fabrics with a relatively smooth surface were treated using chitosan, a natural polymer with excellent biocompatibility, and nanosilver colloid solution, which has strong antibacterial effects even when used in small amounts. The treatment effect was examined at various mixing ratios. When the mixing ratio of the nanosilver solution was higher, antibacterial and deodorization activity was increased. For CH3/NS1 treated fabric, when the mixing ratio of chitosan and nanosilver solution was 3:1, the air permeability was most excellent, and worked as a positive in improving the pleasantness of the sanitary nonwoven fabric. In all samples, the electrostatic propensity was reduced, regardless of the mixing ratio. In terms of the moisture characteristics of chitosan/nanosilver treated nonwoven fabrics, the moisture uptake was found to be superior in the CH3/NS1 treated fabric. When the mixing ratio of the nanosilver solution was higher, moisture permeability decreased, showing a similar tendency to that of air permeability. The vertical water permeability coefficient increased in all treated fabrics. The dynamic water absorption rate was good in CH4 and CH3/NS1 treated fabrics. This means that the absorption of water in the liquid state became easier, thus improving applicability as sanitary nonwoven fabrics.  相似文献   

4.
Fabric porosity is the result of fabric constructional parameters combination and used technology of nonwoven production. The effects of fabric porosity structure, as well as the content of hydrophilic viscose and hydrophobic polyester fibres in the web mixture, on the vertical wicking rate by nonwoven fabrics have been explored in this research. Fibrous webs with a different content of viscose and polyester fibres, with the web volume mass range of 0.019-0.035 g/cm3 were utilized during this study. The samples were produced using a dry-laid method of web forming and two methods of web bonding, e.g. needle punching and calendar bonding. Results show that higher volume porosity gives higher vertical wicking rate by all groups of tested samples regarding the content of used hydrophilic/hydrophobic fibres and that fluid flow is faster in samples with larger pores. The higher content of viscose fibres improve the vertical wicking rate, but better rising height can be achieved at samples made from 100 % of coarser polyester fibres. A prediction model of vertical wicking rate of viscose/ polyester nonwovens was developed on the basis of the fundamental constructional parameters of nonwoven fabrics (fibre fineness, type of raw material, and web density) and a non-deterministic modelling method, e.g. genetic algorithms, which can serve as a useful tool for fabric engineers by developing a nonwoven fabric in order to fit desired wicking rate.  相似文献   

5.
A new coupled model (PCPF–SWMS) was developed for simulating fate and behavior of pollutant in paddy water and paddy soil. The model coupled the PCPF-1, a lumped model simulating pesticide concentrations in paddy water and 1 cm-surface sediment compartment, and the SWMS-2D, a finite element numerical model solving Richard's and advection-dispersion equations for solute transport in soil compartment. The coupling involved improvements on interactions of the water flow and the concentration the pollutant of at the soil interface between both compartments. The monitoring data collected from experimental plots in Tsukuba, Japan in 1998 and 1999 were used to parameterise and calibrate hydraulic functioning, hydrodynamic and hydrodispersive parameters of the paddy soil. The analysis on the hydraulic functioning of paddy soil revealed that the hard pan layer was the key factor controlling percolation rate and tracer transport. Matric potential and tracer monitoring highlighted the evolution of saturated hydraulic conductivity (K S) of hard pan layer during the crop season. K S slightly decreased after puddling by clay clogging and strongly increased after mid term drainage by drying cracks. The model was able to calculate residential time in every soil layers. Residential time of tracer in top saturated layers was evaluated to be less than 40 days. It took 60 days to reach the unsaturated layers below hardpan layer.  相似文献   

6.
In this research work, the thermo physiological properties of polyester/polyethylene nonwoven composite wraps of varying thicknesses impregnated with aerogel were studied and compared. The SEM images were also taken to compare the physical configuaration of the aerogel based fibrous composites. Specific thermal properties like thermal conductivity, thermal resistance, thermal diffusivity and thermal absorptivity were measured using alambeta instrument. The air permeability of the thermal wraps was measured in air permeability tester. The relative water vapor permeability and absolute water vapor permeability was measured in Permetest. These tests were conducted to understand thermal properties, air and water vapor permeability of flexible aerogel based composites with nanoporous structure. The results of the experiments were statistically analyzed and found to be within confidence intervals.  相似文献   

7.
Permeability of the preform is one of key factors in design of RTM (Resin Transfer Molding) mold, determination of processing conditions, and modeling of flow in the mold. According to previous studies, permeability measured in the unsaturated fiber mats are higher than that in the saturated fiber mats by about 20 % because of the capillary pressure. In this study, permeabilities of several fiber preforms are measured for both saturated and unsaturated flows. A saturated experiment of radial flow has been adopted to measure the permeability of anisotropic fiber preforms with high fiber content, i.e., circular braided preforms. In this method, four pressure transducers are used to measure the pressure distribution. Permeabilities in different directions are determined and the experimental results show a good agreement with the theory. Since permeability is affected by the capillary effect, permeability should be measured in the unsaturated condition for the textile composites to be manufactured under lower pressure as in the Vacuum Assisted Resin Transfer Molding (VARTM).  相似文献   

8.
Vertical wicking model was developed based on Darcy’s law. In the model, permeability coefficient, capillary pressure and fabric thickness were used as the key parameters to describe wicking behavior. For the simulation and test, fiber type and fabric structure were chosen as variables. In a highly porous knit fabric, gravitational effect during the wicking process was significant. The higher the capillary pressure was, the higher was the wicking rise. Surface wetting tension, i.e., the specific fluid affinity of material, was newly defined to characterize different capillary pressures in various types of fabric structures. The model, the methodology and the results could provide an insight into fabric design to produce fabric with an optimum wicking performance.  相似文献   

9.
An eco-friendly shore protection system for preventing the erosion of shore surfaces has been developed using water permeable geocomposites that allow grass to take root in them. The geocomposites require enough stiffness to resist the flow of the water in the stream and good permeability of the flowing water. In this study, a geocomposite is designed using multi-axial warp knitted fabric (MAWKF) and nonwoven mats to ensure both the mechanical stiffness and water absorption. Firstly, a stress analysis is performed for a shore protection system to calculate stresses which are imposed onto geocomposites. To test geocomposites?? capacity to withstand the stress, the geometrical modeling of a MAWKF is carried out and the mechanical behavior of its unit-cell is analyzed using finite element method. Comparing the predicted results with experiments, the validity of the current modeling is demonstrated. Finally the adaptability of the geocomposite is evaluated using the calculated deformation.  相似文献   

10.
A double-layer nonwoven fabric containing Tencel, cotton, and chitosan was prepared by the immersion-precipitation phase-inversion method and evaluated as a wound covering. Macroporous structure of the chitosan membrane could control evaporative water loss, promote fluid drainage, and inhibit exogenous micro-organisms invasion due to inherent antimicrobial property of the chitosan. The chitosan membrane was hemostatic and could accelerate the healing of the wound. Histological examination showed that epithelialization rate was increased and the deposition of collagen in the dermis was well organized by covering the wound with the membrane. These results indicate that the chitosan-coated Tencel/cotton nonwoven fabric can be a potential material employed as a wound dressing.  相似文献   

11.
A series of some novel hybrid materials prepared via a sol-gel process have been synthesized from methyltrimethoxysilane and titanium n-butoxide with heterocyclic thiazole azo dyes. Silica/titania/thiazole azo dyes hybrid materials were synthesized via a sol-gel process with a precursor system. Alternatively, the heterocyclic thiazole azo dyes were catalytically processed by means of hydrolysis-condensation reactions with appropriate amounts of a mixture of vinyltriethoxysilane, methyltrimethoxysilane, and titanium n-butoxide at a fixed molar ratio. The structure of these hybrid silica/titania/thiazole dye materials was characterized by Fourier transform infrared (FT-IR) analysis. The surface morphology of processed PET/PA6 nonwoven fabrics was evaluated by scanning electron microscopy (SEM). SEM images showed uniform dyeing, thereby confirming the reaction of the hybrid materials with the PET/PA6 nonwoven fabrics. The water contact angle, washing fastness, color evenness, air permeability, and weatherability characteristics of the as-prepared dyed PET/PA6 nonwoven fabrics were subsequently evaluated. Results revealed improved weatherability and good water repellency. Further, it was also revealed that dyeing and finishing could be achieved in a single bath, which is advantageous to reduce processing costs.  相似文献   

12.
Calcium alginate nonwoven fabrics were gelation-modified by two-stage with aqueous HCl solution and then ethanolic NaOH solution. The structure and crystallinity properties of the samples were characterized by FT-IR, SEM, and XRD. The preparation conditions and modification mechanism were investigated. The results indicated that the crystal structure of calcium alginate fibers was destroyed; the crystallinity and calcium ion content decreased after HCl treatment. This resulted from the formation of ester bonds among the hydrolytic molecules after NaOH treatment. The best gel performance was obtained at the HCl concentration of 0.05-0.1 wt% with the NaOH concentration in ethanol of 2–4 mol/l. The liquid absorption of nonwoven alginate fabrics increased by 145 %. The water capability increased by 2673 % after modification, while the thickness, mass per unit area, permeability, and tensile strength of nonwoven alginate fabrics changed little.  相似文献   

13.
In this work, a series of needle-punched nonwoven filter media was prepared by using polyester fibres of three different cross-sections (circular, trilobal, and deep-groove) in accordance with a three-component augmented simplex lattice design. The experimental data of filtration efficiency and pressure drop were analyzed by means of response surface methodology. Statistical model equations were developed for filtration efficiency and pressure drop by using Design-Expert® software. The filtration efficiency and pressure drop were expressed as linear functions of proportion of fibres of different shapes. Statistical checks (ANOVA, R 2 and p-value) indicated that these models were adequate for representing the experimental data. By means of contour plots, the effect of filter constituents on filtration performance was analysed. The filter media consisting of deep-grooved fibres exhibited highest filtration efficiency but at the cost of highest pressure drop. On the other hand, the filter media consisting of circular fibres displayed lowest pressure drop but at the cost of lowest filtration efficiency. As a compromise for simultaneously achieving maximum filtration efficiency of 61.52 % and minimum pressure drop of 13.6 Pa, the optimum mixture was predicted to consist of 53.7 % deep grooved fibres and 46.3 % circular fibres. The predicted response was found in close agreement with the experimental data. This demonstrates the effectiveness of the approach reported here for achieving good predictions, while minimizing number of experiments.  相似文献   

14.
This work deals with the study of acoustic performance of struto nonwovens and their relation to fabric air permeability. In order to achieve the objective of the research, sound absorption coefficient of struto nonwovens was determined via impedance tube method, the average value of sound absorption coefficient (α?) was calculated. Air permeability of struto nonwovens was examined by using FX3300 Textech Air Permeability Tester. Results showed that struto nonwoven exhibited good absorption ability at frequency bands 3000-6400 Hz while it was ineffective for frequency lower than 3000 Hz. Struto nonwovens with high GSM and fabric thickness showed better acoustic performance and lower air permeability. It was observed that α? was inversely proportional to air permeability, with correlation coefficient 0.95. It was concluded that air permeability can be used as a criterion of sound absorption behavior of struto nonwovens. A lower air permeability suggests a better sound absorption performance for struto nonwoven fabrics.  相似文献   

15.
Polyimide (P84) nanofibers of 200-500 nm were deposited uniformly on needle punched aramid felt with basis weight of 260-350 g/m2 by optimized electrospinning. High temperature adhesive was then electro-sprayed on the nanofiber side deliberately to bind a thin protective layer made of temperature-resistant non-wovens. The three layer structure was afterwards enforced by hot pressing to form composite filter media. The application of the adhesive was tailored not to affect the permeability of the substrate felt while exerting adhesion strength of over 1000 kPa for the media to be suitable for flue gas dust treatment under 240 ºC. When 0.3-10 μm NaCl aerosols were used as the simulated dusts, it was found that even a small amount of P84 nanofibers could obviously elevate the filtration efficiency. The composite showed 100 % removal efficiency of particles equal and greater than 2.0 μm, and 99.5 % for particles 1.0-2.0 μm in diameter.  相似文献   

16.
This paper reports the results from the modelling of electrical resistance of polyester reinforced nonwoven fabrics used for light conveyor belts having conductive PA6 fibres and the same value of fabric volume fraction. The modelling was carried out on the basis of nonwoven construction parameters (the content of conductive fibres in nonwoven layers, fabric thickness), a two-probe method of electrical resistance measurement using flat electrodes and common ohmmeter, and a deterministic modelling method, e.g. statistical factor analysis. The results show very good agreement between the experimental and predicted values of conveyor belts’ electrical resistance. The proposed model provides guidelines for the engineering of conveyor belts in order to fit the prescribed electrical resistance.  相似文献   

17.
When floating vegetation grows on the water surface in a closed water body, the vegetation counteracts the magnitude of the wind acting on the water surface, and affects the fluid flow and the water quality variation in it. In this study, in order to investigate the counteraction effect of the luxuriant growth of floating vegetation on the fluid flow and water quality in the closed water body, we conducted hydraulic experiments on wind-induced flow with density stratification using a wind tunnel test tank and imitated vegetation. We used imitated vegetation made from polystyrene foam plates instead of using real floating vegetation. And we experimentally considered the effect of the vegetation using the concept of the wind-induced entrainment phenomenon. In particular, we focused the effect of the occupation rate and the swaying motion of vegetation. The results indicated that the swaying motion of imitated floating vegetation had an effect on the scale of entrainment. In addition the results had the same tendency as the previous study on the wind-induced entrainment phenomenon.  相似文献   

18.
Needle-punched webs for wet cleaning wipes were produced using a dry-laid method of web- forming. Fibrous webs with a different content of hydrophilic viscose and hydrophobic polyester fibers, as well as webs made from 100 % polyester fibers, were utilized during this study. The webs were compared in terms of their water absorption capacity on the basis of their basic construction parameters, such as fiber fineness, raw material (e.g. fiber density), and web density. The higher water absorption capacity of the viscose/polyester-blended needle-punched webs was achieved at higher content of viscose fibers which coincide with the higher fiber density, finer fibers, and lower web density. A prediction model regarding water absorption capacity of viscose/polyester needle-punched webs was developed on the basis of the mentioned construction parameters and a non-deterministic modelling method, e.g. genetic algorithms, and could provide a guideline for the engineering of nonwoven webs in order to fit the desired water absorption capacity.  相似文献   

19.
以皇后帝王花种子为实验材料,对其进行形态解剖、种皮超微结构观测、种皮透水性与含水量检测,以了解皇后帝王花种皮结构与种子休眠的关系。结果表明:(1)皇后帝王花种子的种皮分为3层,外种皮的栅栏结构增强了种子的不透性,高度木质化的中种皮使种子坚硬,内种皮较薄却被一层不易透水的蜡质包裹;(2)酸蚀处理能使皇后帝王花种子种皮表面结构疏松,种皮变薄,种孔露出。但酸蚀4 h种子的中种皮及内种皮已经出现破坏性开裂,严重影响到胚活力;(3)完整干种子与酸蚀0.5 h种子在前14 h均能快速吸水,吸水50 h后近饱和状态,自此,二者吸水率小范围波动直至完全饱和;(4)酸蚀处理种子并不能使胚更好的吸水保水。因此,皇后帝王花种皮结构对胚的吸水并未形成阻碍,但不能排除其对胚呼吸的影响及对胚根的伸长和生长产生机械阻力的可能。  相似文献   

20.
In this study, Polylactic Acid (PLA) nonwoven fabric and thermoplastic polyurethane (TPU) honeycomb air cushion (TPU-HAC) were employed to form an impact resistant layer for functional knee pads. PLA nonwoven fabric has low manufacture cost and flexibility of the honeycomb air cushion improved the quality of functional knee pad sold in the market. This study focused on the strength of PLA nonwovens and the impact resistance of TPU honeycomb air pads. The PLA fibers and low-melting-point (low-Tm) PLA fibers are used as raw materials to fabricate PLA nonwoven fabric. The PLA fibers and low-melting-point PLA fibers were mixed at weight ratios of 10, 20, 30, 40, and 50 %. PLA nonwoven fabric and TPU-HAC materials were combined in a sandwich structure to protect against impact. Impact resistance was evaluated using a falling-weight impact-resistance machine. Experimental findings indicate that changing various layers can improve the impact resistance of the sandwich structure of the TPU-HAC materials. A TPU-HAC layer with a thickness of 2/8/10 mm optimized the impact resistance. In 25 J falling-weight impact test, the TPU-HAC layer 2/8/10 mm provides an impact resistance of 2932 N; the PLA/TPU-HAC composite had the best impact resistance; 2516 N. PLA nonwoven fabric had the best mechanical properties with low-Tm PLA fibers at 30 % weight. The impact resistance achieved using above combination of materials met the level 2, range 3 impact values mentioned in EN 14120 standards.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号