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1.
The porosity of fibrous porous materials is an important factor to the thermal insulating performance of the material. This paper considers both the optimum porosity of uniform fibrous battings and the optimum distribution of the porosity of non-uniform fibrous battings for thermal insulation. The former was determined by an approximate analytical solution and a numerical simulation by using finite volume method, and the latter was studied by applying simulated annealing method. The study showed that the optimum porosity of uniform fibrous porous materials is very much dependent on fiber emissivity, and fiber radius, but little influenced by the temperature difference of the boundaries. For non-uniform fibrous materials, there can be an optimum distribution of porosity, which can be predicted by applying the simulated annealing method.  相似文献   

2.
Air permeability is one of the most important utility properties of textile materials as it influences air flow through textile material. Air permeability plays a significant role in well-being due to its influence on physiological comfort. The air permeability of textile materials depends on their porosity. There are a lot of structural properties of textile materials also operating parameters (knitting+finishing) influencing air permeability and there are also statistically significant interactions between the main factors influencing the air permeability of knitted fabrics made from pure yarn cotton (cellulose) and viscose (regenerated cellulose) fibers and plated knitted with elasthane (Lycra) fibers. Two types of artificial neural networks (ANNs) model have been set up before modeling procedure by utilizing multilayer feed forward neural networks, which take into account the generality and the specificity of the product families respectively. A virtual leave one out approach dealing with over fitting phenomenon and allowing the selection of the optimal neural network architecture was used. Moreover this study exhibited that air permeability could be predicted with high accuracy for stretch plain knitted fabrics treated with different finishing processes. Within the framework of the work presented, ANNs were applied to help industry to adjust the operating parameter before the actual manufacturing to reach the desired air permeability and satisfy their consumers.  相似文献   

3.
Enzyme degradation method was adopted to prepare porous m-aramid/cellulose blend membranes with high air permeability, water absorbency and moisture permeability. This facile preparation process started by casting a blend membrane from a DMAc/LiCl solution containing m-aramid and cellulose. An enzyme was then used to degrade the cellulose in the blend membrane, resulting in porous structures. Five enzymes including cellulase, chitosanase, papain, lipase, and glucose oxidase, were evaluated and cellulase was found to be optimal. Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) were used to characterize the miscibility and the morphology of the m-aramid/cellulose blend membranes before and after degradation, respectively. The thermal stability of the blend membranes were characterized by thermogravimetric analysis (TGA). The properties including air permeability, water absorbency and moisture permeability of the m-aramid/cellulose blend membranes greatly improved after degradation as compared to those of the pure m-aramid. This paper provided a new approach to preparing novel textile materials with high comfortability.  相似文献   

4.
The computational fluid dynamics (CFD) has been applied to simulate heat transfer in complex and porous materials, and the governing partial differential equation (PDE) has been used to solve this kinds of models by means of numerical approach. The solution of the governing differential equations has been obtained using the Crank-Nicolson method. The main problem in these methods is lack of accurate estimation of thermal diffusivity in bulk complex fibrous materials. To overcome this problem, a novel modelling method of heat transfer in transient condition based on training of a propagation neural network has been applied to analyze heat transfer. The neural net model has been evaluated by experimental data of polyester samples of bulky fibrous layers. The results present that propagation neural net can estimate thermal diffusivity of samples with good accuracy.  相似文献   

5.
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   

6.
The aim of this study was to analyze and model the effect of knitting parameters on the air permeability of Cotton/Polyester double layer interlock knitted fabrics. Fabric samples of areal densities ranging from 315–488 g/m2 were knitted using yarns of three different cotton/polyester blends, each of two different linear densities by systematically varying knitting loop lengths for achieving different cover factors. It was found that by changing the polyester content in the inner and outer fabric layer from 52 to 65 % in the double layer knitted fabric did not have statistically significant effect on the fabric air permeability. Air permeability sharply increased with increase in knitting loop length owing to decrease in fabric areal density. Decrease in yarn linear density (tex) resulted in increase in air permeability due to decrease in areal density as well as the fabric thickness. It was concluded that response surface regression modeling could adequately model the effect of knitting parameters on the double layer knitted fabric air permeability. The model was validated by unseen data set and it was found that the actual and predicted values were in good agreement with each other with less than 10 % absolute error. Sensitivity analysis was also performed to find out the relative contribution of each input parameter on the air permeability of the double layer interlock knitted fabrics.  相似文献   

7.
This work was discussed on the morphology and crystal structure on electrospun fibrous PB membrane, namely, both highly porous PB film and the fibrous PB nonwoven prepared by the same method of electrospinning process. Both the tip-to-collector distance (TCD) and the surrounding temperature were crucial parameters for determining the resulting morphologies. In terms of shorter TCD (below 10 cm) and lower surrounding temperature (below 40 °C), highly porous PB film was almost electrospun because such shorter distance and lower temperature were completely not enough to evaporate the used solvents during electrospinning. Fibrous PB nonwoven, however, was obtained at longer TCD and higher temperature (80 °C). X-ray diffraction (XRD) and differential scanning calorimeter (DSC) analyses demonstrated that a porous PB film revealed two crystal structures of dominant form III and small amount of form II arising from the melt recrystallization from form III crystals, while fibrous PB nonwoven showed form I due to the aging time over 2 weeks at room temperature after electrospinning. As a result, it was found that PB membrane can exhibits a porous film and fibrous nonwoven with different morphologies and crystalline microstructures depending on TDC and surrounding temperature although they were prepared from the same method of electrospinning.  相似文献   

8.
This research investigated the effect of repeated laundering and dry-cleaning on the physical and thermophysiological comfort properties such as air permeability, water vapour resistance and thermal resistance of fabrics made of meta-aramid (Nomex®) fibre. Two different types of fabric were selected for the study and subjected to repeated laundering and dry-cleaning (1, 5 and 10 cycles), which is commercially used for the care and maintenance of these fabrics. The fabric thickness, areal density, thermal resistance and water vapour resistance values increased with the number of laundering cycles, whereas the air permeability decreased due to the fabric shrinkage and swelling. On the other hand, the thickness and air permeability of the dry-cleaned fabric samples increased with the number of cycles; while the water vapour resistance and thermal resistance decreased. The scanning electron microscopy images showed the structural changes as indicated by the longitudinal fibrillation in the fabrics subjected to laundering or dry-cleaning.  相似文献   

9.
The permeability defined by Darcy’s law indicates the degree of ability that a fluid can flow through nonwoven media under a differential pressure in laminar flow. The permeability generally indicates the specific permeability or absolute permeability. On the other hand, if the fluid is water, the permeability indicates the hydraulic conductivity or permeability coefficient. The permeability is one of the important properties for nonwoven media and a prediction of the permeability acts as a bridge between the manufacturing technology and performance requirements. Because capillary channel theory aims to make the flow of fluid easier and more understandable, many models are based on capillary channel theory. On the other hand, the theory has a limitation in that it is unsuitable for high porosity media. In this study, a very thin downstream layer, which was suggested by Lifshutz [9], was introduced to derive a prediction model of hydraulic permeability. Needle-punched and spunbonded nonwoven fabrics with various basis weights were used in the cross-plain water permeability test. From this ‘thin layer’ model, reasonable agreement between the predicted and experimental results was obtained.  相似文献   

10.
The aim of this study was to model the air permeability of polyester cotton blended woven fabrics. Fabrics of varying construction parameters i.e. yarn linear densities and thread densities were selected and tested for air permeability, fabric areal density and fabric thickness. A total of 135 different fabric constructions were tested among which 117 were allocated for development of prediction model while the remaining were utilized for its validation. Four variables were selected as input parameters on basis of statistical analysis i.e. warp yarn linear density, weft yarn linear density, ends per 25 mm and picks per 25 mm. Response surface regression was applied on the collected data set in order to develop the prediction model of the selected variables. The model showed satisfactory predictability when applied on unseen data and yielded an absolute average error of 5.1 %. The developed model can be effectively used for prediction of air permeability of the woven fabrics.  相似文献   

11.
Hanji (Korean traditional paper) yarn displays excellent humidity control, air permeability, and absorbency as well as pleasantness to the touch due to its structural characteristics, and thus, it has been developed as a new eco-friendly fibrous materials. In this study, Hanji, having a basis weight of 8 and 10 g/m2, was prepared using mulberry fibers. The prepared Hanji was cut into Hanji tape of 5–10 mm in width using a rotary slitter and then the tape was twisted to manufacture Hanji yarn. To ensure a uniform twist of Hanji yarn and a smooth twisting process, a water supply system was designed to provide water directly at the twisting zone. At a fixed spindle speed, the feeding speed of the delivery roller was varied to provide different twist numbers for the Hanji yarn. The Hanji yarn manufactured with water treatment has higher tensile properties and a softer touch than the Hanji yarn prepared without water treatment. The Hanji yarns have count numbers of 7–11 Ne and tensile strengths of 1.0–1.2 gf/d. Moreover, the fabric from Hanji yarn shows an excellent color fastness of 4.0 grade, staining of 4–5 to washing, and 4–5 grade to dry cleaning.  相似文献   

12.
Hyaluronate and alginate are non-toxic and biocompatible polymers, which can be used for surface modification and functionalization of many kinds of materials. Electrophoretic deposition (EPD) has several advantages, including its versatility, simplicity, and ability to coat substrates with complex shapes, and is used for the creation of antimicrobial or hydrophobic coatings on metallic biomaterials, among other applications. However, its utilization for applying biopolymer layers on textiles is very limited due to the more complex structure and spatial characteristics of fibrous materials. The aim of this research was to analyze the effects of selected EPD process parameters and the structural characteristics of fibrous carriers on the kinetics of the process and the microscopic characteristics of the deposited layers. The influence of solution characteristics, process parameters, and carrier structures obtained using two different techniques (melt blown and spun-bonded) were analyzed. The morphology and structure of the created deposits were analyzed using scanning electron microscopy and computed tomography, and molecular structure analysis was performed with Fourier Transform Infrared spectroscopy. The surface mass and thickness of fibrous poly (lactic acid)-based carriers were analyzed in accordance with the respective standards. This study serves as a basis for discussion and further development of this method with regard to fibrous materials for medical applications.  相似文献   

13.
Layered fabric systems with electrospun polyurethane fiber web layered on spunbonded nonwoven were developed to examine the feasibility of developing protective textile materials as barriers to liquid penetration using electrospinning. Barrier performance was evaluated for layered fabric systems, using pesticide mixtures that represent a range of surface tension and viscosity. Air permeability and water vapor transmission were assessed as indications of thermal comfort performance. Protection performance and air/moisture vapor transport properties were compared for layered fabric systems and existing materials for personal protective equipment (PPE). Layered fabric systems with electrospun nanofiber web showed barrier performance in the range between microporous materials and nonwovens used for protective clothing. Layered fabric structures with the web area density of 1.0 and 2.0 g/m2 exhibited air permeability higher than most PPE materials currently in use; moisture vapor transport was in a range comparable to nonwovens and typical woven work clothing fabrics. Comparisons of layered fabric systems and currently available PPE materials indicate that barrier/transport properties that may not be attainable with existing PPE materials could be achieved from layered fabric systems with electrospun nanofibrous web.  相似文献   

14.
Waterproof breathable layered fabrics allow water vapor passing through, but resist liquid water to pass. This ability of the fabrics to protect rain and snow water while allowing sweat vapor to evaporate from inside to outside atmosphere, leads them to be used as outdoor sportswear or protective clothing. The big challenge of enhanced hydrostatic resistance of these fabrics with proper breathability and thermal comfort has widened the research scope. This study presents an experimental investigation on hydrostatic resistance and thermal behavior of layered waterproof breathable fabrics. Six different types of hydrophobic and hydrophilic membrane laminated layered fabrics were evaluated by varying different fabric parameters in the experiment. Hydrostatic resistance and water vapor permeability of the laminated fabrics were measured by SDL ATLAS Hydrostatic Head Tester and PERMETEST respectively. Thermal properties were evaluated by ALAMBETA instrument. Moreover, FX-3300 air permeability tester was used to measure air permeability which represents the porosity of the fabrics and computer based See System software was used for water contact angle measurement on the outer fabric surface in order to determine the hydrophobic and hydrophilic properties. This experiment clearly discusses the influence of different fabric characteristics and parameters on hydrostatic resistance and thermal properties of the breathable laminated fabrics. The results show that fabric material composition, density, thickness, and hydrophobic and hydrophilic membranes have significant effects on hydrostatic resistance, breathability and thermal properties of different laminated fabrics.  相似文献   

15.
In this study, fire-retardant polyester fibers (FRPFs), which are hollow and have a 3D-crimp shape, were processed using nonwoven manufacturing technology to create fire-retardant fibrous material. The content of low-T m fibers (10, 20, 30, 40, 50 %) and number of layers of loose nonwoven sheet (1, 2, 3, 4, 5 layers) were changed to determine tensile strength and elongation, thermal conductivity, air permeability and the limiting oxygen index. The purposes of this study are to develop a manufacturing procedure for convenient installation of thermal insulation material and improve the application of fiber materials in thermal insulation. Experimental results demonstrate that, due to the loose nonwoven sheet combined with needle punching nonwoven sheets, tensile strength FRPFs increased to 100 %. The contents of the polyester low-melting-temperature fiber and the number of combined layers affected thermal conductivity results. In the test for the limit oxygen index, the optimal sample was manufactured using 7.78 dtex FRPFs, 10 % PET low-melting-temperature fiber and 5 layers of loose nonwoven sheet. The limit oxygen index is 35.  相似文献   

16.
Lee  Kwang Ju  Kim  Seong Hun  Oh  Kyung Wha 《Fibers and Polymers》2004,5(4):280-288
Split-type nylon/polyester microfiber and polyester microfiber fabrics possess drapeability, softness, bulkiness, and smoothness, so that they can be applied in various industrial fields. In particular, these fabrics are able to absorb various organic solvents, and can be used as clean room materials. To investigate the chemical affinity between solvents and the compositional materials of these fabrics, the contact angle of thermally pressed film fabrics was measured with different solvents. The thermally pressed nylon/polyester fabric films showed a chemical attraction to formamide. The sorption properties of the microfiber fabrics were investigated using a real time testing device, and these tests showed that the sorption behavior was more influenced by the structure of the fibrous assembly than by any chemical attraction. The effect of the fabric density, specific weight, and sample structure on the sorption capacity and rate was examined for various organic solvents. The sorption capacity was influenced by the density and the specific weight of the fibrous assembly, and knitted fabric showed a higher sorption capacity than woven fabric. However, the sorption rate was less affected in lower viscosity solvents. On applying Poiseuille’s Law, the lower viscosity solvents showed higher initial sorption rates, and more easily penetrated into the fibrous assembly.  相似文献   

17.
This study presents a theoretical and experimental investigation of the process of drying of fabrics on a continuously moving flat plate. A mathematical model is developed for heat and mass transfer analysis of fabric in the impingement dryers. For simplicity, it is assumed that during the drying period of the fabric has porous media and on the drying surface the vapour pressure of the evaporating liquid remains at a quasi-saturated value corresponding to the temperature of the liquid. Using the model, the calculated transient fabric temperatures in the impingement dryers agree well with the experimental results.  相似文献   

18.
A series of hybrid materials composed of boehmite/silica/thiazole dyes and prepared via the sol-gel process is synthesized from aluminum isopropoxide (AIP) and tetraethoxysilane using heteroaryl 2-amino-thiazole azo dyes. Heterocyclic 2-amino-thiazole azo dyes undergo a hydrolysis-condensation reaction with an appropriate proportion of AIP under a catalyst, at a constant ratio of vinyltriethoxysilane (VTES) and tetraethoxysilane (TEOS). The structures of these hybrid materials composed of boehmite/silica/thiazole dyes are characterized using Fourier transform infrared (FT-IR) analysis. The surface morphology of polyethylene terephthalate (PET) fabrics is evaluated using scanning electron microscopy (SEM). SEM images show uniform dyeing of the PET fabrics that confirms the reaction of the hybrid materials with the PET fabrics. The water contact angle, washing fastness, color evenness, air permeability, and warmth retention of the PET fabrics dyed with hybrid materials composed of boehmite/silica/thiazole dyes are evaluated. The evaluation results indicate improved warmth retention property and good water repellency.  相似文献   

19.
Tencel Jacquard fabric is one of the eco-fabrics used for underwear, sportswear, bedclothes, clothes for aged people, and hospital textiles. It is popular for these uses because it is easy to process into yarns and fabrics alone or in blends, very stable in washing and drying, thermally stable, and easy to dye with deep vibrant colors using direct, reactive, or vat dyes. In order to provide antimicrobial properties for Tencel Jacquard fabrics, they were treated with ginkgo biloba extract and silicon softener using two different processes so the results could be compared. One of the processes treated the fabrics with ginkgo biloba extract and silicon softener simultaneously, and the other process treated the fabrics with these agents sequentially. The treated Tencel Jacquard fabrics were characterized by scanning electron microscopy, and their antimicrobial properties were evaluated. In addition, water repellency, air permeability, water vapor permeability, and yellowness were measured. It was observed that the ginkgo biloba extract and silicon softener were present on the surface of the treated fibers, and the quantity of these agents before and after laundering was proportional to the measured antimicrobial activity of the fabrics before and after laundering. Fabrics treated with both agents had stronger water/oil repellency than fabrics treated with only ginkgo biloba extract. As the quantities of the two treating agents on fabrics were increased, their air permeability and water vapor permeability decreased. No significant changes were observed for yellowness based on the amounts of treating agents applied. From these results, it is expected that Tencel fabrics treated with ginkgo biloba extract and silicon softener are excellent for use as bedclothes.  相似文献   

20.
Moisture management behavior is a vital factor in evaluating thermal and physiological comfort of functional textiles. This research work studies functional 3 dimensional (3D) warp knitted spacer fabrics containing high-wicking materials characterized by their profiled cross section. These spacer fabrics can be used for protective vest to absorb a user’s sweat, to reduce the humidity and improve user’s thermal comfort. For this reason, different 3D warp knitted spacer fabrics were produced with functional fiber yarns in the back layer of the fabric (close to the body) and polyester in the front and middle layers (outer surface). Comfort properties such as air and water vapor permeability and wicking and other moisture management properties (MMP) of different fabric samples were measured. It is demonstrated that by using profiled fibers such as Coolmax fiber, moisture management properties of spacer fabrics can be improved, enabling them to be use as a snug-fitting shirt worn under protective vests with improved comfort.  相似文献   

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