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Wikipedia[note 3] is a free content online encyclopedia written and maintained by a community of volunteers, known as Wikipedians, through open collaboration and the use of the wiki-based editing system MediaWiki. Wikipedia is the largest and most-read reference work in history.[3][4] It is consistently ranked as one of the ten most popular ...
The first set of data on the left columns of the table includes estimates for the year 2023 made for each economy of the 196 economies (189 U.N. member states and 7 areas of Aruba, Hong Kong, Kosovo, Macau, Palestine, Puerto Rico, and Taiwan) covered by the International Monetary Fund (IMF)'s International Financial Statistics (IFS) database.
- History
- Chemical and Physical Properties
- Production
- Manufacturing from Polypropylene
- Applications
- Repairing
- Health Concerns
- Combustibility
- External Links
Phillips Petroleum chemists J. Paul Hogan and Robert Banks first demonstrated the polymerization of propylene in 1951. The stereoselective polymerization to the isotactic was discovered by Giulio Natta and Karl Rehn in March 1954. This pioneering discovery led to large-scale commercial production of isotactic polypropylene by the Italian firm Monte...
Polypropylene is in little aspects similar to polyethylene, especially in solution behavior and electrical properties. The methyl group improves mechanical properties and thermal resistance, although the chemical resistance decreases.: 19 The properties of polypropylene depend on the molecular weight and molecular weight distribution, crystallinity...
Polypropylene is produced by the chain-growth polymerization of propene: The industrial production processes can be grouped into gas phase polymerization, bulk polymerization and slurrypolymerization. All state-of-the-art processes use either gas-phase or bulk reactor systems. 1. In gas-phase and slurry-reactors, the polymer is formed around hetero...
Melting process of polypropylene can be achieved via extrusion and molding. Common extrusion methods include production of melt-blown and spun-bond fibers to form long rolls for future conversion into a wide range of useful products, such as face masks, filters, diapers and wipes. The most common shaping technique is injection molding, which is use...
As polypropylene is resistant to fatigue, most plastic living hinges, such as those on flip-top bottles, are made from this material. However, it is important to ensure that chain molecules are oriented across the hinge to maximise strength. Polypropylene is used in the manufacturing of piping systems, both ones concerned with high purity and ones ...
PP objects can be joined with a two-part epoxyglue or using hot-glue guns. PP can be melted using a speed tip weldingtechnique. With speed welding, the plastic welder, similar to a soldering iron in appearance and wattage, is fitted with a feed tube for the plastic weld rod. The speed tip heats the rod and the substrate, while at the same time it p...
The advocacy organization Environmental Working Group classifies PP as of low to moderate hazard.[why?]PP is dope-dyed; no water is used in its dyeing, in contrast with cotton.
Like all organic compounds, polypropylene is combustible. The flash point of a typical composition is 260 °C; autoignition temperatureis 388 °C.
Mexico,[a][b] officially the United Mexican States,[c] is a country in the southern portion of North America. It covers 1,972,550 km2 (761,610 sq mi),[11] making it the world's 13th-largest country by area; with a population of almost 130 million, it is the 10th-most-populous country and the most populous Spanish-speaking country.[12] Mexico ...
