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Nanotextiles and Recent Developments
Published in Asis Patnaik, Sweta Patnaik, Fibres to Smart Textiles, 2019
Rajkishore Nayak, Asimananda Khandual
Melt blowing is a simple, versatile and one-step process to produce materials in micrometre and smaller scale (Nayak 2012). The technology of melt blowing was first developed in 1950s at the Naval Research Laboratory of United States. In melt-blowing process, a molten polymer is extruded through the orifice of a die. The fibres are formed by the elongation of the polymer streams coming out of the orifice by air drag and are collected on the surface of a suitable collector in the form of web (Nayak 2017). The average fibre diameter mainly depends on the throughput rate, melt viscosity, melt temperature, air temperature and air velocity (Nayak et al. 2013). A brief review of the melt-blowing process and the factors affecting the properties of the web have been reported by various researchers. The schematic of the melt-blowing equipment has been shown in Figure 18.10.
Nanofibers: General Aspects and Applications
Published in Raj K. Keservani, Anil K. Sharma, Rajesh K. Kesharwani, Drug Delivery Approaches and Nanosystems, 2017
Raghavendra Ramalingam, Kantha Deivi Arunachalam
Melt blowing (MB) is a simple, versatile and one step process for the production of materials in micrometer and nanometer range. A typical MB process involves following components: extruder, metering pumps, die assembly, web formation, and winding. A molten polymer is extruded through the orifice of a die. Figure 8.6 represents the schematic illustration of melt blowing system. The fibers are formed by the elongation of the polymer streams coming out of the orifice by air-drag and are collected on the surface of a suitable collector in the form of a web. The average fiber diameter mainly depends on the throughput rate, melt viscosity, melt temperature, air temperature and air velocity (Nayak et al., 2011). The difficulty in fabricating nanofibers in melt blowing is due to the inability to design sufficiently small orifice in the die and the high viscosity of the polymeric melt. Nanofibers can be fabricated by special die designs with a small orifice, reducing the viscosity of the polymeric melt and suitable modification of the melt blowing setup. For example, Ellison et al. (2007) produced melt blown nanofibers of different polymers by a special designed single-hole die with small orifice. The use of small orifices made by an electric discharge machine for the production of super-hydrophobic nanofibers and microfibers has been reported.
Control of Occupational Risks
Published in Małgorzata Pośniak, Emerging Chemical Risks in the Work Environment, 2020
Pneumothermic fabrics obtained by the melt-blown method, also known as the technique of molten polymer blowing, allow producing filter materials from fibers with submicron diameters. If it is assumed that they have a circular cross section, then the average diameter of fibers, in the case of fabrics with high aerosol filtration efficiency, is in the range of 0.3–0.7 μm. Fabrics are also produced from fibers with a diameter distribution from 1 to several micrometers. The greater the differences in fiber sizes, the less uniform the structure of these fabrics. The melt-blown method allows producing fabrics with very high filtration properties.
Recycled cotton/polyester and polypropylene nonwoven hybrid composite materials for house hold applications
Published in The Journal of The Textile Institute, 2022
Santhanam Sakthivel, Fasika Abedom Tesfamicael, Seblework Mekonnen, Eshetu Solomon, Mekdes Gedilu, Selvaraj Senthil Kumar, Boominathan SenthilKumar
The relationship between static bonding strength and the mean fiber diameter is shown in Figure 1. With the enhancement of the static bonding strength, the mean of the fiber diameter decreased. As is shown in the data, increased static strength leads to finer fibers and narrower diameter distribution. The static bonding-assisted melt-blown nonwoven fabric has more fine fibers, especially at 0.6–0.9µm, and the fiber diameter distribution of static-assisted melt-blown fabric is concentrated at 0–4µm, which leads to a decrease in mean diameter. By introducing the static melt-blown process, the mean diameter of the fabric is decreased from 1.69 to 0.96µm, which is about a 40% reduction in fiber diameter. The figure shows the static bonding of nonwoven composites was strongly influenced by air-laid nonwoven composites. The values significantly increased for all air-laid nonwoven composite materials in comparison to melt bellowing nonwoven composites. The results revealed that the high modulus of elasticity of the air laid nonwoven composites, by their thickness and also their location of the nonwoven composites. The same finding was observed by Sanadi et al. (1999); Abdellaoui et al. (2015); Santhanam et al. (2018).
Comparison of the relative performance efficiencies of melt-blown and glass fiber filter media for managing fine particles
Published in Aerosol Science and Technology, 2018
Sungho Hwang, Jaehoon Roh, Wha Me Park
Melt blowing is a process for producing fibrous nonwovens or articles directly from polymers or resins using high-velocity air or other appropriate forces to attenuate the filaments. Melt-blown (MB) fabrics generally have the same applications as other nonwoven products such as sorbents (Wei et al. 2003), hygiene products (Wehmann et al. 2012), and drug delivery (Balogh et al. 2015). Porous nonwoven MB fabrics can also be used for filtration of gaseous and liquid materials. Their applications include water treatment, respiratory protective devices, and air conditioning filters (Dutton 2008). The use of HEPA filters in ventilation systems depends on the design of the filter and its protection class. However, MB nonwoven fabrics have not been used in negative pressure systems for controlling asbestos particles in South Korea when removing asbestos from indoor environments.
Numerical modelling of microfibers formation and motion during melt blowing
Published in The Journal of The Textile Institute, 2018
G. W. Sun, J. Song, L. Xu, X. H. Wang
Melt blowing (MB) is a one-step process where the molten polymer is issued through an orifice with fine tube into a high-speed subsonic hot air jet. The polymer jet is stretched and accelerated by the air jet, meanwhile, a drastic deformation and whipping take place. Expansion of the air jet under the nozzle also leads to a drop in the air temperature which helps to cool the molten polymer. Then the polymer solidifies gradually and is deposited onto a moving collection screen, forming nonwoven web. It is usually used to manufacture nonwoven webs composed of microfibers with diameter less than 10 μm and even 1 μm, though nanometer fibers was also reported. The nonwoven products can be used for air purification, liquid filtration, oil absorption, and face mask, etc. MB fiber properties have a strong impact on the MB products. For example, the filter performance of MB products with fine fiber is better than those with thick fiber. MB theoretical model become increasingly important for fabricating fibers with expected properties.