Melt blowing is a conventional fabrication method of micro- and nanofibers where a polymer melt is extruded through small nozzles surrounded by high speed blowing gas. The randomly deposited fibers form a nonwoven sheet product applicable for filtration, sorbents, apparels and drug delivery systems. The substantial benefits of melt blowing are simplicity, high specific productivity and solvent-free operation. Choosing an appropriate combination of polymers with optimized

rheological Rheology (; ) is the study of the flow of matter, primarily in a fluid (liquid or gas) state, but also as "soft solids" or solids under conditions in which they respond with plastic flow rather than deforming elastically in response to an appli ...

and surface properties, scientists have been able to produce melt-blown fibers with an average diameter as small as 36 nm.

History

During volcanic activity a fibrous material may be drawn by vigorous wind from molten basaltic magma called Pele's hair. 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. Later on,

Exxon Corporation ExxonMobil Corporation (commonly shortened to Exxon) is an American multinational oil and gas corporation headquartered in Irving, Texas. It is the largest direct descendant of John D. Rockefeller's Standard Oil, and was formed on November 30 ...

developed the first industrial process based on the melt blowing principle with high throughput levels. China produces 40% of the non-woven fabric in the world with the majority produced in

Hebei Hebei or , (; alternately Hopeh) is a northern province of China. Hebei is China's sixth most populous province, with over 75 million people. Shijiazhuang is the capital city. The province is 96% Han Chinese, 3% Manchu, 0.8% Hui, an ...

province (2018).

Polymers

Polymers with thermoplastic behavior are applicable for melt blowing. The main polymer types commonly processed with melt blowing: *

Polypropylene Polypropylene (PP), also known as polypropene, is a thermoplastic polymer used in a wide variety of applications. It is produced via chain-growth polymerization from the monomer propylene. Polypropylene belongs to the group of polyolefins and ...

Polystyrene Polystyrene (PS) is a synthetic polymer made from monomers of the aromatic hydrocarbon styrene. Polystyrene can be solid or foamed. General-purpose polystyrene is clear, hard, and brittle. It is an inexpensive resin per unit weight. It is a ...

Polyesters Polyester is a category of polymers that contain the ester functional group in every repeat unit of their main chain. As a specific material, it most commonly refers to a type called polyethylene terephthalate (PET). Polyesters include natural ...

Polyurethane Polyurethane (; often abbreviated PUR and PU) refers to a class of polymers composed of organic chemistry, organic units joined by carbamate (urethane) links. In contrast to other common polymers such as polyethylene and polystyrene, polyurethan ...

Polyamides A polyamide is a polymer with repeating units linked by amide bonds. Polyamides occur both naturally and artificially. Examples of naturally occurring polyamides are proteins, such as wool and silk. Artificially made polyamides can be made throug ...

(

nylon Nylon is a generic designation for a family of synthetic polymers composed of polyamides ( repeating units linked by amide links).The polyamides may be aliphatic or semi-aromatic. Nylon is a silk-like thermoplastic, generally made from petro ...

s) *

Polyethylene Polyethylene or polythene (abbreviated PE; IUPAC name polyethene or poly(methylene)) is the most commonly produced plastic. It is a polymer, primarily used for packaging ( plastic bags, plastic films, geomembranes and containers including bo ...

Polycarbonate Polycarbonates (PC) are a group of thermoplastic polymers containing carbonate groups in their chemical structures. Polycarbonates used in engineering are strong, tough materials, and some grades are optically transparent. They are easily work ...

Uses

The main uses of melt-blown nonwovens and other innovative approaches are as follows.

Filtration

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.

Sorbents

Nonwoven materials can retain liquids several times their own weight. Thus, those made from polypropylene are ideal for collecting oil contamination.

Hygiene products

The high absorption of melt-blown fabrics is exploited in disposable diapers and feminine hygiene products.

Apparels

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

Drug delivery

Melt blowing can produce drug-loaded fibers for controlled

drug delivery Drug delivery refers to approaches, formulations, manufacturing techniques, storage systems, and technologies involved in transporting a pharmaceutical compound to its target site to achieve a desired therapeutic effect. Principles related to d ...

. 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.

References

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External links

What is Melt-Blown Extrusion and How is it Used for Making Masks?
Polymer physics Nanomaterials