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1.
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   

2.
The use of nonwoven textile substrates for filtration and absorption purposes is generalized due to the high surface area they can provide. Many of these applications require good wetting properties to increase efficiency. In this work, low pressure plasma treatment with a CH4-O2 mixture gas has been used to increase surface wettability and subsequent absorption properties on nonwoven polypropylene substrates. CH4 plasma treatment leads to a plasma polymerization process which results in hydrophobic surface finishing, but in combination with O2, it is possible to form a functionalized plasmapolymerized layer thus improving wetting properties. Changes in wetting properties have been studied by contact angle measurements showing that optimum wetting properties are obtained with exposure times to plasma treatment of about 10 min, and no significant changes are obtained for longer exposure times. Absorption efficiency has been followed by determining three different parameters by the guidelines of the UNE-EN-ISO 9073-6 standard: wetting time, liquid absorption capacity (LAC) and liquid propagation rate or absorption speed. All these properties are remarkably improved as the exposure time to CH4-O2 plasma increases; this improvement is remarkably high for relatively short exposure times (5?C10 min) and no significant changes are obtained for long exposure times so that, it is possible to conclude that previous plasma treatment with exposure times in the 5?C10 min range is an efficient method to improve overall absorption properties of nonwoven polypropylene substrates.  相似文献   

3.
The main aim of this research is to systematize the reinforced-earth wall system using the geosynthetic reinforcements in the weathered granite backfill soils containing relatively large amount of fines with low permeability. As a staged endeavor to accomplish this purpose, laboratory pullout tests and finite element modeling are carried out focusing on the analysis of friction characteristics associated with interaction behaviors of the geosynthetic reinforcements composed of geogrid with outstanding tensile resistance and geotextile with a sufficient drainage properties. In addition, drainage effects of the geotextile laid below the geogrid are examined based on the analysis of finite difference numerical modeling. From the present investigation, it is concluded that the geosynthetic reinforcements in the weathered granite backfills can be used to achieve combined effects of the reduction of deformations and the increase of tensile resistance, together with drainage effects.  相似文献   

4.
Plasma surface treatment has been extensively applied in the textile industry for the modification of polymer materials. In this study, polypropylene (PP) fibers in the form of a nonwoven web were treated with low-pressure plasma (air, N2, Ar) for different treatment time (5–40 min). Powers varied from (50–500 W). Surface properties were studied by measuring wetting time and hydrophilisation diameters after an exposure time of 20 seconds. This study showed that the best conditions for the surface modification of nonwoven PP, with low pressure plasma were a power of 500 W and a treatment time of 30 minutes. Ageing has some effect on the wettability of treated samples.  相似文献   

5.
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   

6.
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   

7.
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   

8.
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   

9.
The effects of the material and treatment parameters on airflow resistivity and normal-incidence sound absorption coefficient of alkalized three layered nonwoven composites have been studied. The material parameters included fiber size and porosity. The treatment factors included the temperature, duration and concentration. The alkalized composite was a three-layered nonwoven sandwich structure consisting layers of Polypropylene/Hemp/Polypropylene. Alkalization treatment has been found to result in a loss of basis weight and a decrease in air flow resistivity. Among treatment factors, only temperature was found to be a statistically-significant factor on air flow resistivity. Higher-temperature alkalization leads to higher air flow resistivity compared to the lower-temperature treatment. Alkalization at higher temperature and higher concentrations gives better results in normalized sound absorption performance compared to lower-temperature and lower-concentration treatments, respectively.  相似文献   

10.
This study takes polyacrylonitrile (PAN) as a raw material for PAN-based nanofiber nonwoven prepared using electrospinning. First we construct a thermal-stable process for the fabrication of oxidized nanofiber nonwovens as the precursor. A semi-open high-temperature erect furnace is then used with steam as the activator, through carbonization and activation processes to prepare carbon nanofiber absorbents continuously. The experiment varies the production rate and activator flow rate to prepare carbon nanofiber absorbents. Experimental results show that carbon nanofiber adsorbents are primarily made up of micropores and mesopores, averaging under 20 Å. Given a production rate of 10–20 cm/min with a matching activator feed rate of 120 ml/min, the specific surface area can reach about 1000 m2/g, producing an adsorption ratio of carbon tetrachloride over 200 %.  相似文献   

11.
Silver nanoparticles (AgNPs) were attached to glass fiber filters to improve their antibacterial properties using glycidyltrimethylammonium chloride (GTAC), a type of quaternary ammonium salt. The glass fiber filters treated with GTAC were placed into the Ag colloid and heat-treated at 43 °C for 90 min to attach AgNPs to the glass fiber filters. The glass fiber filters with the attached AgNPs were then analyzed by scanning electron microscopy and atomic force microscopy (AFM). The surface morphology of the glass fiber filters treated with GTAC and AgNPs was observed. The Ag atomic % of the glass fiber filters was analyzed according to the GTAC concentration, Ag colloid concentration, and AgNPs treatment temperature. The surface roughness of the glass fiber filters with the attached AgNPs was measured by AFM. The antibacterial tests of the GTAC and AgNP-treated glass fiber filters highlighted the sufficient antibacterial effects against E. coli, S. aureus, and P. aeruginosa. In particular, the antibacterial properties of glass fiber filters against S. aureus and P. aeruginosa were improved when the glass fiber filters were treated with both GTAC and AgNPs.  相似文献   

12.
Electrospinning is an efficient method to produce polymer fibers with a diameter range from nanometers to a few microns using an electrically driven jet. Electrospun nanofiber nonwoven fabrics can be applied into different areas with higher air volume fraction, especially applied into textile materials with good warmth retention property. In this article, the air volume fraction in nonwoven mats made of electrospun nanofibers was verified by studying fiber volume fraction in the mats. Then the relationship between fiber volume fraction and fiber diameter was derived, and the fiber volume fraction is in direct ratio to the square of fiber radius. By experimental verification, to get electrospun PAN nanofiber nonwoven mats with high air volume fraction about 99 %, it can fix the polymer concentration on 8 %. The voltage fixed on 20 kV, the tip-to-collector distance on 15 cm. The experiment is in accordance with the theory excellently.  相似文献   

13.
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   

14.
The perpendicular-laid nonwoven fabrics may show high loft performance because of the structure composition, which has much fiber oriented in the thickness direction. The ability to maintain the thickness after the cyclic loading is a basic requirement of good high lofts. When the perpendicular-laid nonwoven fabrics are put to practical use as a cushion material, the compressional properties of the cyclic loading should be significant. In this study, a compressional fatigue system has been developed and evaluated with two kinds of perpendicular-laid nonwoven fabrics with different manufacturing processes. The system equation developed provides a stress profile that can be used for analyzing the practical compressional fatigue. The fiber structure of the perpendicular-laid nonwoven fabrics was investigated by using the orientation distribution function (ODF).  相似文献   

15.
2021年7月18-21日河南省漯河地区连续4 d强降雨共计185.60 mm，正值当地夏玉米孕穗期。在渍涝发生后，在河南省漯河市的中国农业科学院作物科学研究所试验田，通过设置雨停后立即排水(T1)、雨停后立即排水+滴灌追氮肥(T2)、雨停后3 d排水(T3)、雨停后3 d排水+滴灌追氮肥(T4)共4个应对措施和不处理(CK)共5个处理，测定不同处理下关键生育期的地上与地下部生物量、叶面积指数及产量相关性状。结果表明，CK处理(5 d后田间无地表积水)绝产，其他4个处理获得平均产量6.98 t/hm2，其中，及时排水处理产量平均较3 d后排水处理提高21.28%，及时排水后施肥处理较不施肥处理产量提高8.07%，3 d后排水并施肥处理较仅排水不施肥处理产量提高15.33%，较及时排水处理低5.04%。及时排水、补充氮肥缓解了涝渍对根系生长、叶面积及地上部干物质积累的负面影响，从而降低产量损失，是应对玉米孕穗期渍涝的有效手段。  相似文献   

16.
In the first stage, polyethylene terephthalate (PET) fibers and Kevlar fibers are combined at a blending ratio of 80/ 20 wt% in order to form PET/Kevlar nonwoven fabrics. Two pieces of PET/Kevlar nonwoven fabrics that enclose a carbonfiber (CF) interlayer are then needle punched in order to form PET/Kevlar/CF (PKC) composites. In the second stage, the sandwiches compose PKC composites as the top and the bottom layers, as well as an interlayer that is composed of a spacer fabric and polyurethane (PU) foam. PU foams have different densities of 200, 210, 220, 230, and 240 kg/m3. These resulting nonwoven fabric/spacer fabric/PU foam sandwiches are then tested using a drop-weight impact test, a compression test, a bursting strength test, a sound absorption test, and a horizontal burning test. The test results indicate that the optimal properties of sandwiches occur with their corresponding PU foam density as follows: an optimal residual stress (240 kg/m3), an optimal compressive strength (240 kg/m3), and an optimal bursting strength (220 kg/m3). In addition, the sandwiches reach the HF1 level according to the horizontal burning test results. They also have an average electromagnetic interference shielding effectiveness of -48 dB, as well as a sound absorption coefficient of 0.5 in a frequency between 1500-2500 Hz, which indicates a satisfactory sound absorption effect. The nonwoven fabric/spacer fabric/PU foam sandwiches proposed in this study are mechanically strong, sound absorbent, and fire retardant, and can be used in construction material and electromagnetic shielding composites.  相似文献   

17.
不同耕作方式对瘠薄型黑土区土壤结构的影响   总被引：5，自引：0，他引：5  
通过深松和玉米秸秆粉碎直接覆盖、秸秆粉碎0～20 cm耕层混拌方式,分析深松和秸秆不同还田方式对土壤容重、孔隙度、三相比及硬度的影响,研究秸秆添加腐解剂快速腐解后土壤物理特性的变化。结果表明,通过深松和秸秆还田后土壤结构均较未深松对照(CK)明显改善,土壤三相比较试验播种前趋于合理,田间持水量和孔隙度较CK明显提高,田间持水量提高3.30～6.78个百分点,孔隙度提高2.90～5.63个百分点,其中秸秆粉碎耕层混拌+腐解剂处理表现最好;其次是秸秆粉碎覆盖+腐解剂。土壤硬度变化表明,收获期秸秆粉碎覆盖+腐解剂和秸秆粉碎耕层混拌+腐解剂处理土壤硬度在地表0～10 cm较CK降低74.4%和65.1%;11～20 cm土壤硬度较CK降低58.6%和56.1%;秸秆粉碎覆盖和秸秆粉碎耕层混拌处理土壤硬度在地表0～10 cm较CK降低80.3%和43.7%,11～20 cm土壤硬度分别较CK降低56.7%和15.5%。试验表明,深松+秸秆粉碎还田处理明显降低土壤硬度,改善土壤结构,腐解剂在雨水充沛时期发挥效果明显。  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.
In recent years, flexible, mechanically strong and environmental friendly thermal insulation materials have attracted considerable attention. In this work, silica aerogel/polyethylene terephthalate (PET) nonwoven fiber composite with desirable characteristics was prepared via a two-step sol-gel process followed by an ambient drying method through immersing the PET nonwoven fiber into silica sol. The silica aerogel particles were characterized by FTIR, FE-SEM, TGA and nitrogen adsorption analysis. The morphology and hydrophobic properties of neat PET nonwoven fiber and its silica aerogel composite were also investigated. For studying thermal protective properties, the thermal diffusivity was calculated from temperature distribution curves. The mean pore size of 11 nm, the surface area of 606 m2/g and the total pore volume of 1.77 cm3/g for the silica aerogel particles in the composite are obtained from nitrogen adsorption analysis, indicating the aerogel can maintain its high porosity in the nonwoven composite structure. Silica aerogel particles were efficiently covered the surface of the PET fibers and completely filled the micron size pores of the nonwoven fiber leading to a stronger hydrophobicity and higher thermal insulation performance in the aerogel composite samples compared to the neat PET nonwoven. In this regard, an almost 64 % decrease in the thermal diffusivity was achieved with 66 wt% silica aerogel.  相似文献   

20.
The thermal characteristics of hollow polyester fibers were compared with solid polyester fibers in order to study their processing behavior and performance characteristics. The effects of different processing and structural properties including fiber diameter, bulk density of layer, and surface pressure on layers of needle-punched nonwoven fabrics with hollow fibers on thermal resistance properties were also investigated. The results show that hollow fibers have a higher thermal resistance in comparison with solid ones. This is a consequence of air trapping inside the fibers, higher bulkiness, and higher surface area of hollow fibers. Furthermore, thermal resistance of microfibers is better than those of macrofibers in both hollow and solid fibers. The thermal resistance of nonwoven subjected to this study, have an inverted-U-shaped pattern versus the bulk density of the fabric. The results also showed that thermal resistance of needle-punched nonwoven fabrics can be affected by the range of heater temperature during the test, however considerably can be affected by fabric thickness as a main structural property of nonwoven fabrics.  相似文献   

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