Melt blowing

During volcanic activity a fibrous material may be drawn by vigorous wind from molten basaltic magma called Pele's hair.{{cite journal|author=Shimozuru, D.|title=Physical parameters governing the formation of Pele's hair and tears|journal=Bulletin of Volcanology|year=1994|volume=56|issue=3|pages=217–219|doi=10.1007/s004450050030|bibcode=1994BVol...56..217S}} The same phenomenon applies for melt blowing of polymers. The first research on melt blowing was a naval attempt in the US to produce fine filtration materials for radiation measurements on drone aircraft in the 1950s.{{cite journal|author=Shaumbaugh, R.L.|title=A macroscopic view of the melt-blowing process for producing microfibers|journal=Ind. Eng. Chem. Res.|year=1988|volume=27|issue=12|pages=2363–2372|doi=10.1021/ie00084a021}} Later on, Exxon Corporation developed the first industrial process based on the melt blowing principle with high throughput levels.{{cite journal|vauthors=Ellison CJ, Phatak A, Giles DW, Macosko CW, Bates FS|title=Melt blown nanofibers: Fiber diameter distributions and onset of fiber breakup|journal=Polymer|year=2007|volume=48|issue=11|pages=3306–3316|doi=10.1016/j.polymer.2007.04.005}} China produces 40% of the non-woven fabric in the world with the majority produced in Hebei province (2018).{{Cite web|first= |last= |authorlink= |title=China export credit insurance company releases domestic mask supply and demand risk analysis and outlook |website= Textile Net China|date=February 17, 2020 |url=http://info.texnet.com.cn/detail-791310.html |accessdate=}}

Polymers with thermoplastic behavior are applicable for melt blowing. The main polymer types commonly processed with melt blowing:{{cite journal|last=Dutton|first=Kathryn C.|title=Overview and analysis of the meltblown process and parameters|journal=Journal of Textile and Apparel, Technology and Management|year=2008|volume=6|url=https://ojs.cnr.ncsu.edu/index.php/JTATM/article/view/342}}

• Polypropylene
• Polystyrene
• Polyesters
• Polyurethane
• Polyamides (nylons)
• Polyethylene
• Polycarbonate

Melt blowing is a manufacturing process used to create nonwoven fabrics and materials. It is particularly known for its ability to produce fine fibers, which can be used in various applications. Here's an overview of how melt blowing works:[https://www.nwfabric.com/ask/meltblown-nonwoven-manufacturing-process/ melt blown nonwoven process] Retrieved 7 June 2016.

• Melt Extrusion: The process begins with a polymer resin being melted and extruded through a spinneret, which is a device with tiny holes.
• High-Speed Airflow: Simultaneously, high-speed hot air or gas is blown onto the extruded polymer streams.
• Fiber Formation: The force of the air stretches and elongates the molten polymer into very fine fibers, which are then collected on a moving conveyor belt or drum.

File:Внешний слой медицинской маски (поляризация).jpg

The main uses of melt-blown nonwovens and other innovative approaches are as follows.{{cite journal|last=McCulloch|first=John G.|title=The history of the development of melt blowing technology|journal=International Nonwovens Journal|year=1999|volume=8|pages=1558925099OS–80|doi=10.1177/1558925099os-800123|doi-access=free}}

Nonwoven melt-blown fabrics are porous. As a result, they can filter liquids and gases. Their applications include water treatment, masks, and air-conditioning filters. During the COVID-19 pandemic, the price of meltblown spiked from few thousand USD per ton to approximately 100 thousand USD per ton.

Nonwoven materials can retain liquids several times their own weight. Thus, those made from polypropylene are ideal for collecting oil contamination.{{cite journal|author=Wei, Q. F.|author2=Mather, R. R.|author3=Fotheringham, A. F.|author4=Yang, R. D.|name-list-style=amp|title=Evaluation of nonwoven polypropylene oil sorbents in marine oil-spill recovery|journal=Marine Pollution Bulletin|year=2003|volume=46|issue=6|pages=780–783|doi=10.1016/s0025-326x(03)00042-0|pmid=12787586}}{{cite journal|author= Sarbatly R.|author2=Kamin, Z.|author3=Krishnaiah D.|name-list-style=amp|title=A review of polymer nanofibres by electrospinning and their application in oil-water separation for cleaning up marine oil spills|journal=Marine Pollution Bulletin|year=2016|volume=106|issue=1–2|pages=8–16|doi=10.1016/j.marpolbul.2016.03.037|pmid=27016959}}

The high absorption of melt-blown fabrics is exploited in disposable diapers and feminine hygiene products.{{cite book|last1=Wehmann|first1=Michael|last2=McCulloch|first2=W. John G.|editor-last=Karger-Kocsis|editor-first=J.|chapter=Melt blowing technology|title=Polypropylene: an A-Z reference|series=Polymer Science and Technology Series|date=2012|volume=2|pages=415–420|publisher=Springer Science & Business Media|doi=10.1007/978-94-011-4421-6_58|isbn=978-94-010-5899-5}}

Melt-blown fabrics have three qualities that help make them useful for clothing, especially in harsh environments: thermal insulation, relative moisture resistance and breathability.

Melt blowing can produce drug-loaded fibers for controlled drug delivery.{{cite journal|author=Balogh, A.|author2=Farkas, B.|author3=Faragó, K.|author4=Farkas, A.|author5=Wagner, I.|author6=Van Assche, I.|display-authors=etal|title=Melt-blown and electrospun drug-loaded polymer fiber mats for dissolution enhancement: A comparative study|journal=Journal of Pharmaceutical Sciences|year=2015|volume=104|issue=5|pages=1767–1776|doi=10.1002/jps.24399|pmid=25761776|url=http://real.mtak.hu/28275/1/Final_MB_MES_ES_2015_JPS.pdf}} The high drug throughput rate (extrusion feeding), solvent-free operation and increased surface area of the product make melt blowing a promising new formulation technique.

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• [https://www.thomasnet.com/articles/machinery-tools-supplies/what-is-melt-blown-extrusion/ What is Melt-Blown Extrusion and How is it Used for Making Masks?]

Category:Polymer physics

Category:Nanomaterials