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Encyclopedia > Polypropylene
Polypropylene
IUPAC name poly(1-methylethylene)
Other names Polypropylene; Polypropene;
Polipropene 25 [USAN];Propene polymers;
Propylene polymers; 1-Propene homopolymer
Identifiers
CAS number 9003-07-0
Properties
Molecular formula (C3H6)x
Density Amorphous: 0.85 g/cm3

Crystalline: 0.95 g/cm3 Image File history File links No higher resolution available. ... IUPAC nomenclature is a system of naming chemical compounds and of describing the science of chemistry in general. ... CAS registry numbers are unique numerical identifiers for chemical compounds, polymers, biological sequences, mixtures and alloys. ... A chemical formula is a concise way of expressing information about the atoms that constitute a particular chemical compound. ... For other uses, see Density (disambiguation). ...

Melting point

~ 165 °C The melting point of a crystalline solid is the temperature range at which it changes state from solid to liquid. ...

Except where noted otherwise, data are given for
materials in their standard state
(at 25 °C, 100 kPa)

Infobox disclaimer and references
Polypropylene lid of a Tic Tacs box, with a living hinge and the resin identification code under its flap
Micrograph of polypropylene

Polypropylene or polypropene (PP) is a thermoplastic polymer, made by the chemical industry and used in a wide variety of applications, including food packaging, ropes, textiles, stationery, plastic parts and reusable containers of various types, laboratory equipment, loudspeakers, automotive components, and polymer banknotes. Additionally it is used commonly in New Zealand and by the US Military as Thermal Underwear. An addition polymer made from the monomer propylene, it is rugged and unusually resistant to many chemical solvents, bases and acids. Its resin identification code is . The plimsoll symbol as used in shipping In chemistry, the standard state of a material is its state at 1 bar (100 kilopascals exactly). ... Image File history File links Download high resolution version (736x1020, 28 KB) Empty Tic Tacs box. ... Image File history File links Download high resolution version (736x1020, 28 KB) Empty Tic Tacs box. ... A couple of boxes of Australian Peppermint-flavored Tic Tacs Polypropylene lid of a Tic Tacs box, with a living hinge and the resin identification code under its flap Two US Cinnamon flavored Tic Tacs on a Tic Tac box This article describes a brand of mints. ... A living hinge on the lid of a Tic Tacs box A living hinge is a hinge with no moving parts. ... Sorted household plastic waiting to be hauled away for reprocessing. ... Image File history File links Size of this preview: 786 × 600 pixel Image in higher resolution (2192 × 1672 pixel, file size: 1. ... Image File history File links Size of this preview: 786 × 600 pixel Image in higher resolution (2192 × 1672 pixel, file size: 1. ... For other uses, see Plastic (disambiguation). ... A polymer (from Greek: πολυ, polu, many; and μέρος, meros, part) is a substance composed of molecules with large molecular mass composed of repeating structural units, or monomers, connected by covalent chemical bonds. ... The chemical industry comprises the companies that produce industrial chemicals. ... It has been suggested that this article or section be merged with Packaging and labelling. ... Coils of rope used for long-line fishing A rope (IPA: ) is a length of fibers, twisted or braided together to improve strength for pulling and connecting. ... For other uses, see Textile (disambiguation). ... Stationery is a general name given to paper and office supplies such as envelopes, notepads, pens, pencils, erasers, paper clips, staples, etc. ... A loudspeaker is a device which converts an electrical signal into sound. ... The first Guardian polymer banknote in circulation. ... An addition polymer is a polymer which is formed by an addition reaction, where many monomers bond together via rearrangement of bonds without the loss of any atom or molecule. ... Propylene, also known by its IUPAC name propene, is an organic compound having the chemical formula C3H6. ... Sorted household plastic waiting to be hauled away for reprocessing. ... Image File history File links Resin-identification-code-5-PP.svg‎ Self made from PNG. File historyClick on a date/time to view the file as it appeared at that time. ...

Contents

Chemical and physical properties

Most commercial polypropylene has an intermediate level of crystallinity between that of low density polyethylene (LDPE) and high density polyethylene (HDPE); its Young's modulus is also intermediate. Although it is less tough than HDPE and less flexible than LDPE, it is much less brittle than HDPE. This allows polypropylene to be used as a replacement for engineering plastics, such as ABS. Polypropylene is rugged, often somewhat stiffer than some other plastics, reasonably economical, and can be made translucent when uncolored but not completely transparent as polystyrene, acrylic or certain other plastics can be made. It can also be made opaque and/or have many kinds of colors. Polypropylene has very good resistance to fatigue, so that most plastic living hinges, such as those on flip-top bottles, are made from this material. Very thin sheets of polypropylene are used as a dielectric within certain high performance pulse and low loss RF capacitors. For other uses, see Crystal (disambiguation). ... This article does not cite any references or sources. ... Polyethylene or polyethene is one of the simplest and most inexpensive polymers. ... Polyethylene or polyethene is one of the simplest and most inexpensive polymers. ... In solid mechanics, Youngs modulus (E) is a measure of the stiffness of a given material. ... Engineering plastics are a group of plastic materials that exhibit superior mechanical and thermal properties in a wide range of conditions over and above more commonly used ‘commodity’ plastics. ... Monomers in ABS polymer Acrylonitrile butadiene styrene, or ABS, (chemical formula (C8H8· C4H6·C3H3N)n is a common thermoplastic used to make light, rigid, molded products such as piping, golf club heads (used for its good shock absorbance), automotive body parts, wheel covers, enclosures, protective head gear, and toys including... In optics, transparency is the property of being transparent, or allowing light to pass. ... Polystyrene (IPA: ) is a polymer made from the monomer styrene, a liquid hydrocarbon that is commercially manufactured from petroleum by the chemical industry. ... Polymethyl methacrylate (PMMA) or poly (methyl 2-methylpropenoate) is the synthetic polymer of methyl methacrylate. ... A substance or object that is opaque is neither transparent nor translucent. ... In materials science, fatigue is the progressive, localised, and permanent structural damage that occurs when a material is subjected to cyclic or fluctuating strains at nominal stresses that have maximum values less than (often much less than) the static yield strength of the material. ... A living hinge on the lid of a Tic Tacs box A living hinge is a hinge with no moving parts. ... A dielectric is a physical model commonly used to describe how an electric field behaves inside a material. ... Pulsed power is the science and technology of accumulating energy over a relatively long period of time and releasing it very quickly. ... It has been suggested that this article or section be merged with Radio waves. ... Various types of capacitors A capacitor is a device that stores energy in the electric field created between a pair of conductors on which equal but opposite electric charges have been placed. ...


Polypropylene has a melting point of 320 °F (160 °C). Many plastic items for medical or laboratory use can be made from polypropylene because it can withstand the heat in an autoclave. Food containers made from it will not melt in the dishwasher, and do not melt during industrial hot filling processes. For this reason, most plastic tubs for dairy products are polypropylene sealed with aluminium foil (both heat-resistant materials). After the product has cooled, the tubs are often given lids of a cheaper (and less heat-resistant) material, such as LDPE or polystyrene. Such containers provide a good hands-on example of the difference in modulus, since the rubbery (softer, more flexible) feeling of LDPE with respect to PP of the same thickness is readily apparent. Rugged, translucent, reusable plastic containers made in a wide variety of shapes and sizes for consumers from various companies such as Rubbermaid and Sterilite are commonly made of polypropylene, although the lids are often made of somewhat more flexible LDPE so they can snap on to the container to close it. When liquid, powdered, or similar consumer products come in disposable plastic bottles which do not need the improved properties of polypropylene, the containers are often made of slightly more economical polyethylene, although transparent plastics such as polyethylene terephthalate are also used for appearance. Plastic pails, car batteries, wastebaskets, cooler containers, dishes and pitchers are often made of polypropylene or HDPE, both of which commonly have rather similar appearance, feel, and properties at ambient temperature. Front loading autoclaves are common Stovetop autoclaves need to be monitored carefully and are the simplest of all autoclaves Multiple large autoclaves are used for processing substantial quantities of laboratory equipment prior to reuse, and infectious material prior to disposal. ... Polystyrene (IPA: ) is a polymer made from the monomer styrene, a liquid hydrocarbon that is commercially manufactured from petroleum by the chemical industry. ... This article does not cite any references or sources. ... See: transparency (optics) alpha compositing GIF#Transparency transparency (overhead projector) market transparency transparency (telecommunication) transparency (computing) For X11 pseudo-transparency, see pseudo-transparency. ... Polyethylene terephthalate (aka PET, PETE or the obsolete PETP or PET-P) is a thermoplastic polymer resin of the polyester family and is used in synthetic fibers; beverage, food and other liquid containers; thermoforming applications; and engineering resins often in combination with glass fiber. ...


MFI (Melt Flow Index) identifies the flow speed of the raw material in the process. It helps to fill the plastic mold during the production process. The higher MFI increases, the weaker the raw material gets. Melt Flow Rate is a measure of the ease of flow of the melt of a thermoplastic polymer. ...


It also has Copolymer and Random Copolymer. Copolymer helps stiffness of the PP (Polypropylene). Random Copolymer helps transparent look.


Copolymer is more expensive than Homopolypropylene. Random Copolymer is even higher than copolymer PP.


A rubbery PP can also be made by a specialized synthesis process, as discussed below. Unlike traditional rubber, it can be melted and recycled, making it a thermoplastic. This does not cite any references or sources. ...


Synthesis

Short segments of polypropylene, showing examples of isotactic (above) and syndiotactic (below) tacticity.

An important concept in understanding the link between the structure of polypropylene and its properties is tacticity. The relative orientation of each methyl group (CH3 in the figure at left) relative to the methyl groups on neighboring monomers has a strong effect on the finished polymer's ability to form crystals, because each methyl group takes up space and constrains backbone bending. Image File history File links Short segments of polypropylene, showing examples of isotactic (above) and syndiotatctic (below) tacticity. ... Image File history File links Short segments of polypropylene, showing examples of isotactic (above) and syndiotatctic (below) tacticity. ... Tacticity (from Greek taktikos: of or relating to arrangement or order) is the relative stereochemistry of adjacent chiral centers within a macromolecule. ... Tacticity (from Greek taktikos: of or relating to arrangement or order) is the relative stereochemistry of adjacent chiral centers within a macromolecule. ... Methyl group In chemistry, a methyl group is a hydrophobic alkyl functional group derived from methane (CH4). ...


Like most other vinyl polymers, useful polypropylene cannot be made by radical polymerization due to the higher reactivity of the allylic hydrogen (leading to dimerization)with respect to polymerization. Moreover, the material that would result from such a process would have methyl groups arranged randomly, so called atactic. The material that results from such a process has methyl groups arranged randomly, and so is called atactic. The lack of long-range order prevents any crystallinity in such a material, giving an amorphous material with very little strength and few redeeming qualities. Chemical structure of the vinyl functional group. ... Radical polymerization is a type of polymerization in which the propagation head of a polymer chain consists of a radical. ... Wax and paraffin are amorphous. ...


A Ziegler-Natta catalyst seems to be able to limit incoming monomers to a specific orientation, only adding them to the polymer chain if they face the right direction. Most commercially available polypropylene is made with titanium chloride catalysts, which produce mostly isotactic polypropylene (the upper chain in the figure above). With the methyl group consistently on one side, such molecules tend to coil into a helical shape; these helices then line up next to one another to form the crystals that give commercial polypropylene its strength. A Ziegler-Natta catalyst is a reagent used in the production of unbranched, stereoregular vinyl polymers. ... Isotactic polymers refer to those polymers formed by branched monomers that have the characteristic of having all the branch groups on the same side of the polymeric chain. ...

A ball-and-stick model of syndiotactic polypropylene.

More precisely-engineered Kaminsky catalysts have been made, which offer a much greater level of control. Based on metallocene molecules, these catalysts use organic groups to control the monomers being added, so that a proper choice of catalyst can produce isotactic, syndiotactic, or atactic polypropylene, or even a combination of these. Aside from this qualitative control, they allow better quantitative control, with a much greater ratio of the desired tacticity than previous Ziegler-Natta techniques. They also produce higher molecular weights than traditional catalysts, which can further improve properties. Image File history File links Download high resolution version (741x741, 287 KB) Summary A ball and stick model of syndiotactic polypropene. ... Image File history File links Download high resolution version (741x741, 287 KB) Summary A ball and stick model of syndiotactic polypropene. ... A syndiotactic macromolecule in polymer chemistry is a tactic macromolecule essentially comprising alternating enantiomeric configurational base units which have chiral or prochiral atoms in the main chain in a unique arrangement with respect to their adjacent constitutional units. ... A Kaminsky catalyst is a catalytic system for olefin polymerization discovered by Walter Kaminsky and coworkers in 1980. ... In chemistry, and in particular, in organometallic chemistry, a metallocene is a compound consisting of an aromatic organic ligand bound to a metal. ... A syndiotactic macromolecule in polymer chemistry is a tactic macromolecule essentially comprising alternating enantiomeric configurational base units which have chiral or prochiral atoms in the main chain in a unique arrangement with respect to their adjacent constitutional units. ...


To produce a rubbery polypropylene, a catalyst can be made which yields isotactic polypropylene, but with the organic groups that influence tacticity held in place by a relatively weak bond. After the catalyst has produced a short length of polymer which is capable of crystallization, light of the proper frequency is used to break this weak bond, and remove the selectivity of the catalyst so that the remaining length of the chain is atactic. The result is a mostly amorphous material with small crystals embedded in it. Since each chain has one end in a crystal but most of its length in the soft, amorphous bulk, the crystalline regions serve the same purpose as vulcanization. Vulcanization refers to a specific curing process of rubber involving high heat and the addition of sulfur. ...


History

Polypropylene was first introduced in 1957. It was the Italian company Montecatini that succeeded in this polymerization. At first it was thought that it would be cheaper than polyethylene.[1] Montecatini is the name of several locations in Tuscany, Italy. ... This article does not cite any references or sources. ...


Practical applications

In New Zealand and also in the US military, polypropylene, or 'polypro' (New Zealand 'polyprops'), is the material used for the fabrication of cold-weather gear, such as a long-sleeve shirt or long underwear, in addition to warm-weather gear such as Under Armor clothing, which can easily wick away sweat. These polypro clothes are not easily flammable, however, they can melt, which may result in severe burns if the service member is involved in an explosion or fire of any kind.[2] Polypropylene is also used as an alternative to polyvinyl chloride (PVC) as insulation for electrical cables for LSZH cable in low-ventilation environments, primarily tunnels. This is because it emits less smoke and no toxic halogens, which may lead to production of acid in high temperature conditions. There are very few or no other articles that link to this one. ...


Polypropylene is also used in particular roofing membranes as the waterproofing top layer of single ply systems as opposed to modified bit systems. Its most common medical use is in the synthetic, nonabsorbable suture Prolene, manufactured by Ethicon Inc. For other uses, see Suture (disambiguation). ... Prolene is a synthetic, nonabsorable polypropylene suture. ... Ethicon, Inc. ...


Polypropylene is most commonly used for plastic mouldings where it is injected into a mould while molten, forming complex shapes at relatively low cost and high volume, examples include bottle tops, bottles and fittings.


Recently it has been produced in sheet form and this has been widely used for the production of stationary folders, packaging and storage boxes. The wide colour range, durability and resistance to dirt make it ideal as a protective cover for papers and other materials. It is used in Rubik's cube stickers because of these characteristics. Variations of Rubiks Cubes (from left to right: Rubiks Revenge, Rubiks Cube, Professors Cube, & Pocket Cube). ...


The availability of sheet polypropylene has provided an opportunity for the use of the material by designers. The light weight, durable and colourful plastic makes an ideal medium for the creation of light shades and a number of designs have been developed using interlocking sections to create elaborate designs.


The material has recently been introduced into the fashion industry through the work of designers such as Anoush Waddington who have developed specialist techniques to create jewellery and wearable items from polypropylene. Anoush Waddington is a leading designer in Art jewelry. ...


PP-R stands for Polypropene-Random, and is a plastic that is used for food containers than need to stand 120 °C, when used with microwave ovens or dishwashers. Polypropylene is a thermoplastic polymer, used in a wide variety of applications, including Australian banknotes. ... Microwave oven A microwave oven, or microwave, is a kitchen appliance employing microwave radiation primarily to cook or heat food. ... A Dishwasher A two drawer DishDrawer dishwasher. ...


Expanded Polypropylene: EPP


References

  1. ^ This week 50 years ago in New Scientist, 28 April, 2007, p. 15
  2. ^ USAF Flying Magazine. Safety. Nov. 2002.

New Scientist is a weekly international science magazine covering recent developments in science and technology for a general English-speaking audience. ...

External links


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