polypropylene


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polypropylene

(pŏl'ēprō`pəlēn), plasticplastic,
any organic material with the ability to flow into a desired shape when heat and pressure are applied to it and to retain the shape when they are withdrawn. Composition and Types of Plastic
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 noted for its light weight, being less dense than water; it is a polymerpolymer
, chemical compound with high molecular weight consisting of a number of structural units linked together by covalent bonds (see chemical bond). The simple molecules that may become structural units are themselves called monomers; two monomers combine to form a dimer,
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 of propylene. It resists moisture, oils, and solvents. Since its melting point is 121°C; (250°F;), it is used in the manufacture of objects that are sterilized in the course of their use. Polypropylene is also used to make textiles, ropes that float, packaging material, and luggage.
The Columbia Electronic Encyclopedia™ Copyright © 2013, Columbia University Press. Licensed from Columbia University Press. All rights reserved. www.cc.columbia.edu/cu/cup/

Polypropylene

A common flexible plastic usually spun into fiber for rope and woven goods.
Illustrated Dictionary of Architecture Copyright © 2012, 2002, 1998 by The McGraw-Hill Companies, Inc. All rights reserved
The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.

Polypropylene

 

a thermoplastic polymer of propylene, [—CH2—CH(CH3)—]n; a colorlesscrystalline substance of iso-tactic structure. Molecular weight M̅w, 300,000–700,000; maximum crystallinity, 73–75 percent; density, 0.92–0.93 g/cm3 at 20°C; melting point, 172°C. Polypropylene has high impact strength (impact strength, notched 5–12 kilojoules per sq m, or kilograms-force · cm per sq cm), high resistance to multiple bending, and low vapor and gas permeability; its durability is comparable to that of the polyamides.

Polypropylene is a good dielectric (power factor, 0.0003–0.0005 at 1 megahertz) and a poor heat conductor. It is insoluble in organic solvents and resistant to boiling water and alkalies, but darkens and decomposes under the influence of HNO3, H2SO4, and chromium mixtures. Since polypropylene has low heat and light resistance, special additives called polymer stabilizers are introduced into the mixture.

Polypropylene is produced by solution or bulk polymerization of a monomer. It is processed by injection molding and extrusion. Polypropylene is used to manufacture fibers and films that retain their ductility at 100°-130°C, as well as expanded plastics, machine parts, shaped products, pipes (for aggressive liquids), various fittings, containers, and household goods.

The amorphous phase, in a 3–7 percent quantity formed during polypropylene synthesis, is isolated from the basic crystalline product and used in the manufacture of rubber household goods and additives for lubricating and motor oils. Polypropylene is produced in the USSR, Italy (Moplen), Great Britain (Propa-thene), the Federal Republic of Germany (Hostalen), and the USA (Poly-pro, Pro-fax). The 1973 world production of polypropylene was estimated at 2.4 million tons.

REFERENCES

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O. N. PIROGOV

The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.

polypropylene

[‚päl·ə′prō·pə‚lēn]
(organic chemistry)
(C3H6)x A crystalline, thermoplastic resin made by the polymerization of propylene, C3H6; the product is hard and tough, resists moisture, oils, and solvents, and withstands temperatures up to 170°C; used to make molded articles, fibers, film, rope, printing plates, and toys.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.

polypropylene

A plastic polymer of propylene; a tough material having good resistance to heat and chemical action.
McGraw-Hill Dictionary of Architecture and Construction. Copyright © 2003 by McGraw-Hill Companies, Inc.
References in periodicals archive ?
The latest report published by QY Research has been analyzed for the global BOPP (bi-axially oriented polypropylene) market for the forecast period of 2018-2023.
Dayanand Kharade, oil and gas analyst at GlobalData, said: "Increasing polypropylene demand mainly from packaging, due to urbanisation and growing income levels, are contributing to large capacity additions in China and India."
Because of its diverse properties, polypropylene lends itself well to a large number of end-use applications.
The key end-user segments covered in this research are bi-axially-oriented polypropylene films, casted polypropylene films, carpet yarns, nonwovens, geotextiles, woven bags, injection molding grade and polypropylene in tje automotive sector.
The largest market for spunmelt polypropylene is hygiene, which commands about two-thirds of the total worldwide capacity of Fine and coarse denier spunmelt polypropylene nonwovens.
Khalid Al Gaithi, Operation Engineer at the polypropylene plant said; "This was a proud moment for all in the polypropylene plant as it achieves the main aim behind the economic ventures; thanks to the team spirit by all employees".
The green polypropylene, says Braskem, will have the same technical, processability and performance properties as polypropylene made using traditional production routes, but with a green ticket.
Compared to global standards the amount of polypropylene used in Indian passenger vehicles is low.
It was found that HMS-PP could be manufactured in several ways, one of which [1] is to improve the melt strength of polypropylene, by broadening its MWD from a combination of more than three polymerizing groups, using Methalosen catalyst or Ziegler-Natta catalyst.
A new polypropylene copolymer is said to provide the toughness and stiffness required for returnable containers, trays, nestable totes, and pallets.
The line at the Kashima factory will manufacture types of polypropylene that are more impact-resistant than other polypropylenes, according to the Mitsubishi Chemical Holdings Corp.