polyvinyl chloride (PVC) | chemical compound | Britannica.com Polyvinyl chloride (PVC) matter Polyvinyl chloride (PVC), a synthetic resin made from the polymerization of vinyl chloride . Second only to polyethylene among the plastics in production and consumption , PVC is used in an enormous range of domestic and industrial products, from raincoats and shower curtains to window frames and indoor plumbing . A lightweight, rigid plastic in its pure form, it is also manufactured in a flexible “plasticized” form. Vinyl chloride is an organohalogen compound that has important industrial applications. When … Encyclopædia Britannica, Inc. Vinyl chloride (CH2=CHCl), also known as chloroethylene, is most often obtained by reacting ethylene with oxygen and hydrogen chloride over a copper catalyst . It is a toxic and carcinogenic gas that is handled under special protective procedures. PVC is made by subjecting vinyl chloride to highly reactive compounds known as free-radical initiators.

Under the action of the initiators, the double bond in the vinyl chloride monomers (single-unit molecules) is opened, and one of the resultant single bonds is used to link together thousands of vinyl chloride monomers to form the repeating units of polymers (large, multiple-unit molecules). The chemical structure of the vinyl chloride repeating units is: PVC was first prepared by the German chemist August Wilhelm von Hofmann in 1872, but it was not patented until 1912, when another German chemist, Friedrich Heinrich August Klatte, used sunlight to initiate the polymerization of vinyl chloride. Commercial application of the plastic was at first limited by its extreme rigidity; however, in 1926, while trying to dehydrohalogenate PVC in a high-boiling solvent in order to obtain an unsaturated polymer that might bond rubber to metal , Waldo Lunsbury Semon , working for the B.F. Goodrich Company in the United States , produced what is now called plasticized PVC. The discovery of this flexible, inert product was responsible for the commercial success of the polymer.

Under the trademark Koroseal, Goodrich made the plastic into shock-absorber seals, electric-wire insulation, and coated cloth products. One of the best-known applications of the plastic was initiated in 1930, when the Union Carbide and Carbon Corporation (later the Union Carbide Corporation ) introduced Vinylite, a copolymer of vinyl chloride and vinyl acetate that became the standard material of long-playing phonograph records. Similar Topics polyvinyl fluoride (PVF) Pure PVC finds application in the construction trades, where its rigidity, strength, and flame resistance are useful in pipes, conduits , siding , window frames, and door frames. It is also blow-molded into clear, transparent bottles. Because of its rigidity, it must be extruded or molded above 100 °C (212 °F)—a temperature high enough to initiate chemical decomposition (in particular, the emission of hydrogen chloride [HCl]). Decomposition can be reduced by the addition of stabilizers, which are mainly compounds of metals such as cadmium , zinc , tin , or lead .

major industrial polymers: Polyvinyl chloride (PVC) In order to arrive at a product that remains flexible, especially at low temperatures, most PVC is heated and mixed with plasticizers , which are sometimes added in concentrations as high as 50 percent. The most commonly used plasticizer is the compound di-2-ethylhexyl phthalate (DEHP), also known as dioctyl phthalate (DOP). Plasticized PVC is familiar to consumers as floor tile, garden hose, imitation leather upholstery, and shower curtains. Learn how tinsel evolved from a source of lead poisoning to its present polyvinyl chloride (PVC) … © American Chemical Society (A Britannica Publishing Partner) Very fine particles of PVC can be dispersed in plasticizer in excess of the amount used to make plasticized PVC (e.g., 50 percent or more), and this suspension can be heated until the polymer particles dissolve. The resultant fluid, called a plastisol, will remain liquid even after cooling but will solidify into a gel upon reheating. Plastisols can be made into products by being spread on fabric or cast into molds.

Flexible gloves can be made by dipping a hand-shaped form into plastisol, and hollow objects such as overshoes can be made by casting plastisol into a mold, pouring off the excess, and solidifying the material remaining on the walls of the mold. Britannica Stories vinyl chloride | chemical compound | Britannica.com chemical compound vinyl fluoride (H 2C=CHF) Vinyl chloride, also called chloroethylene, a colourless, flammable, toxic gas belonging to the family of organohalogen compounds and used principally in making polyvinyl chloride , or PVC, a widely used plastic with numerous applications. The major industrial preparation of vinyl chloride begins with ethylene and has two variants. In one, ethylene is converted to 1,2-dichloroethane ( ethylene chloride ) by reaction with chlorine . Heating 1,2-dichloroethane in the presence of a charcoal catalyst gives vinyl chloride. In the other process (called oxychlorination), ethylene, hydrogen chloride , and oxygen (or air) are heated in the presence of a copper catalyst to give vinyl chloride and water .

Typically, a vinyl chloride plant is designed to integrate the two processes so that the hydrogen chloride produced by heating 1,2-dichloroethane is used as a reactant in the oxychlorination method. Processes based on acetylene were developed in the 1930s and are more direct, but because acetylene is much more expensive than ethylene, these processes are used far less than ethylene-based ones. Vinyl chloride can cause liver damage, and it is classified as a known human carcinogen . organohalogen compound any of a class of organic compounds that contain at least one halogen (fluorine [F], chlorine [Cl], bromine [Br], or iodine [I]) bonded to carbon. They are subdivided into alkyl, vinylic, aryl, and acyl halides. In alkyl halides all four bonds to the carbon that bears the halogen are single bonds;... polyvinyl chloride (PVC) a synthetic resin made from the polymerization of vinyl chloride.

Second only to polyethylene among the plastics in production and consumption, PVC is used in an enormous range of domestic and industrial products, from raincoats and shower curtains to window frames and indoor plumbing. A... plastic polymeric material that has the capability of being molded or shaped, usually by the application of heat and pressure. This property of plasticity, often found in combination with other special properties such as low density, low electrical conductivity, transparency, and toughness, allows plastics... 3 References found in Britannica Articles Assorted References vinylic halides (in organohalogen compound: Reactions ) External Links Corrections? Updates? Help us improve this article! Contact our editors with your feedback. MEDIA FOR: You have successfully emailed this. Error when sending the email. Try again later. Edit Mode Submit Tips For Editing We welcome suggested improvements to any of our articles. You can make it easier for us to review and, hopefully, publish your contribution by keeping a few points in mind. Encyclopædia Britannica articles are written in a neutral objective tone for a general audience. You may find it helpful to search within the site to see how similar or related subjects are covered. Any text you add should be original, not copied from other sources.

At the bottom of the article, feel free to list any sources that support your changes, so that we can fully understand their context. (Internet URLs are the best.) Your contribution may be further edited by our staff, and its publication is subject to our final approval. Unfortunately, our editorial approach may not be able to accommodate all contributions. Submit Thank You for Your Contribution! Our editors will review what you've submitted, and if it meets our criteria, we'll add it to the article. Please note that our editors may make some formatting changes or correct spelling or grammatical errors, and may also contact you if any clarifications are needed. Uh Oh There was a problem with your submission. Please try again later. Close Date Published: July 22, 2008 URL: Access Date: January 05, 2017 Share What is Polyvinyl Chloride? (with pictures) What is Polyvinyl Chloride? Last Modified Date: 01 December 2016 Copyright Protected: Adorable animal families that will make you "aww" Polyvinyl chloride, better known as PVC or vinyl , is an inexpensive plastic so versatile it has become completely pervasive in modern society.

The list of products made from PVC is exhaustive, ranging from phonograph records to drainage and potable piping, water bottles, cling film, credit cards and toys. More uses include window frames, rain gutters, wall paneling, doors, wallpapers, flooring, garden furniture, binders and even pens. Even imitation leather is made of it. In fact, it's hard to turn anywhere without seeing some form of this plastic. In 1913, polyvinyl chloride became the first synthetic product ever patented. Its wide use is now in question, however, as it comes from a highly toxic production industry and potentially remains an environmental threat throughout all phases of its life. In addition to the toxic chemical processing required to make PVC, mounting research indicates a tendency for some products to leech harmful chemicals, with a possible link to health risks and environmental contamination. Additionally, PVC is not biodegradable, a fact that manufacturers promote as a plus, while environmentalists count it among many of the plastic's drawbacks. They point to the ever-growing amounts of discarded products and shrinking landfills, and the potential for long-term leeching that could lead to ground water contamination .

This material should not be burned, as it can release harmful gas, and recycling it is difficult because of the diverse additives used in various products. One of the byproducts of the polyvinyl chloride manufacturing process is organochlorine. Though chlorine is found naturally in the environment in minerals such as salt, this type is different. Highly reactive, its effect in concentrated form can be very destructive, as seen in other manufacturing industries. Some familiar forms of organochlorines include polychlorinated biphenyls (PCBs), banned in the 1970s; halon and CFCs, responsible for destroying the ozone ; and DDT. Purportedly, the production of PVC results in the generation of more organochlorines than any other material. Aside from the environment, human health is also a concern. Studies regarding initial outgassing of chemicals from plastics like those used in shower curtains, flooring and vinyl car interiors are ongoing. Leeching of a softening chemical called DEHP (di-2-ethyl hexyl phthalate ) in products like vinyl IV bags used in the neonatal wards of some hospitals has also been a concern. Alternate softening agents are reportedly under consideration by the industry but require further testing.

Though polyvinyl chloride products have been used without apparent problems to human health for many years, the concern is that growing toxic waste created by the process, possible leeching, and plastic's non-biodegradable status will eventually and inevitably lead to problems that could be catastrophic. The conservative trend is headed towards environmentally friendly, biodegradable alternatives. Among others, these include wood, paper, copper , steel, and clay. Chlorine-free plastics, such as polyethylene (PE), polypropylene (PP) and polyisobutylene, may also be preferred over PVC, although most of these are not biodegradable. Ad Does anybody know about dioxin and burning plastic? Does it cause petechiae? anon295233 Post 27 Dioxins are formed from the incomplete burning of plastic. I believe they are used in the casing of fridge freezers and if your freezer is charred I would advise you to remove it from the house. The mistake I made was getting rid of it. If I still had it environmental health could have checked for dioxins and other possible chemicals. If you do get it checked, could you post back with the results?

anon281649 Post 25 Can anybody tell me if pvc is used on the inside of white goods, e.g. fridges, washing machines, etc. I also have noticed a plastic burning smell inside my freezer and noticed it is charred. Does anybody know how dioxin is created and what the conditions for it to be formed are. anon276907 Post 24 PVC is terrible stuff. I think I have dioxin poisoning from an old fridge freezer which had burnt plastic from inside the freezer compartment. This had been going on for a long time before I realized it. There was a copper pipe inside the actual freezer which was supposed to melt the ice but instead accidentally the plastic guard pushed up against it and it had been melting for a long time. pvc Post 22 I think a big concern with PE products is their ability to degrade. I am not certain if this is as a result of UV radiation and thus only an outdoor concern, but I have never heard of PE replacing PVC in the home. PVC is incredibly easy to install for plumbing and is very resistant to temperature change.

anon230374 Post 21 That was the dumbest thing I have ever heard. You should probably do some more research before posting something as relevant and witless as that. PVC only gives off chloride and you can't get any more from PVC as you could from swimming in a pool that had chlorine in it, and the government doesn't control everything. anon227307 Post 20 Governments quickly lose their ability to care. Concentration camp officials spent the day torturing and killing people and then went home to an apparently 'normal' family life, without a trace of the inhumane treatment they practiced when eliminating the Jews and others they considered undesirables. It can take from five to 50 years for the results of populations being exposed to toxic substances. We are just part of very large experiments -- guinea pigs. anon220128 Post 19 We can't go a single day without coming in contact with something made of PVC. Let's be honest, if PVC were harmful or bad we all would have affects from it and they wouldn't use it in such a variety of products.

Flooring, window frames, door frames, pipes, cars, cords, kitchen appliances, kids toys, house siding, clothes. I mean think about it. Look them up. anon220124 Post 18 The reason this material is massively produced and is used in every day products is because it isn't a harmful plastic when it is processed. What other companies may do with this material can alter it though. Putting in additives, or people using them incorrectly. Burning a thermoset/non biodegradable plastic at a high enough temperature only puts the material back to its original state of carbon compound/soot. anon159836 Post 16 It's slowly taking us out. it's in our water delivery system. Affects male population most. Drink beer. anon132432 Is polyvinylchloride a good fire retardant? --NZMV anon118852 Post 13 This is absolutely crazy! I'd heard of plastic being bad for the environment, but never understood why. I'm currently reading "Hot, Flat, and Crowded", so it's scary how much this goes along with that.

We need some chemical engineers to come up with better materials, and to figure out how to clean up the current mess! Where there's a will, there's a way! anon76638 In response to #5. O.K. I checked your company out.Put down the Kool-Aid, pal. Your company has come up with a way to biodegrade the PVC quickly! Great we all humans love you for that! Thank You for accelerating the off-gassing of pcbs, dioxins, and genetic mutating chemicals by your company's fast degrading of PVC. Chlorine is not biodegradable. All you guys are doing is making it off gas faster to make it brittle and break it down faster. Gee, thanks. I will be sure to tell my sister who has terminal breast cancer from chlorine and dioxin poisoning through outgassing of the foam padding in bras that, through transdermal osmosis, transfer the chlorine dioxin directly into the fatty tissue of her breast. Again, thank you very much. ladies want more info about the REAL cause of breast cancer? write me.

Ill share anon74182 Post 11 I am not a chemist or anything like that but, as a concerned Grandmother, I would like to know why such products are sold as little children's belts, toys, etc. My daughter recently bought belts for her 1 1/2 year old daughter at WalMart and found a label saying it contained chemicals that are known to cause cancer. I think it is shameful to make money selling these products at the risk of our Children's health and lives!!! anon73848 Post 10 is vinyl chloride used in the processing in the photographic industry? please would be most grateful for an answer. anon62388 Post 9 In the 1970s i worked at a wallpaper warehouse in indianapolis, ind. for three years. they specialized in vinyl wallcovering for commercial and residential applications. this was a very large operation with truckloads of this stuff coming in weekly. as i recall most of my coworkers, including me, were sick a lot with chest colds, etc. After reading this article, i wonder if the wallpaper had anything to do with our aliments. m.

cooper Suevette Post 7 I work for a company that fabricates polyethylene foam cushioning. It is made from the resins at a facility I do not frequent. What are the health risks to an individual who is predisposed to health issues by being around the poly vinyl chloride used in manufacturing for the end result planks that are used at our facility? What information do you have regarding the time and proximity of being around the plank product? anon10983 Post 4 As a child I grew up seeing pvc everywhere but only now do I know the effects of this plastic.... I can't believe this! boa Post 3 I beg to differ with you. In the North East USA, PVC dominates commerce so we have little choice. When i was in Kuai (oldest Hawian island) i saw PE plastic pipe with all the usual fittings assemble very easily, in much the same way as PVC. People might not realize that so many products are made with PVCand then are thown out, very often ending up in loocal incinerators and creating poisons which can affect us or our budgets beyonde PVC puchase..

Please use a search engine with both terms: pvc + dioxin Also consider the impact of dioxin. It becomes difficult to appreciate why such harmful practices are so engrained in any good country. anon2312 Post 2 I am not a chemist, but I think a big concern with PE products is their ability to degrade. I am not certain if this is as a result of UV radiation and thus only an outdoor concern, but I have never heard of PE replacing PVC in the home. PVC is incredibly easy to install for plumbing and is very resistant to temperature change. I wish my copper water pipes were PVC since my winter hot water takes forever to warm up. I could easily cut and shape my pipes to add faucets etc, but I do not know how to braze copper pipes together. ANY idiot can put PVC together and so I will have a much harder time with my copper pipe instead of PVC. Burning the stuff is horrid... putting certain softeners with it to make squishy baby teething toys is also stupid, but in the home, PVC rules for a good reason. boa Post 1 I really like this short article as i have been concerned about PVC products.

Why does the NE USA flood the market with PVC?? I buy drain pipeand other building products and feel there is a monopoly with these products in the form of PVC. It is almost mafia like. I would much prefer PE products, knowing i am not stressing or harming future generations with ppolutants. I have seen equal products made with PE, but these are not sold in the NE USA. Why can't the PE industry advertise the benefits of PE over PVC? Post your comments Polyinyl_chloride_PVC Polyvinyl Chloride (PVC) What is Polyvinyl Chloride (PVC)? PVC is Polyvinyl Chloride. This is a plastic that has the following chemical formula: CH2=CHCl (see picture on the right). Plastic covers a wide rage of synthetic or semi-synthetic polymerization products (i.e. long-chain carbon-based "organic" molecules) which name refers to the fact that in their semi-liquid state they are malleable, or have the property of plasticity. PVC is a thermoplastic material. Thermoplastic materials are those that can be melted again and again. These materials can be heated to a certain temperature and will harden again as they cool.

After the First World War, there was a boom in new forms of plastics due to the improvements in the chemical technology sector, including "polystyrene (PS)" and "polyvinyl chloride (PVC)", developed by the I.G. Farben company of Germany. Nowadays, PVC is commonly used in the construction sector, for example in window frames and shutters, pipe cabling and coating, etc.. Vinyl is also used in gramophone records, and that is why we use the term vinyl records to refer to them. PVC can be used for tons of other applications from industrial ware and widely used in the healthcare sector, to car spare parts, toys factory, food packaging, raingear, etc. (This is described below). PVC can be clear or colored, rigid or flexible, depending on the added compounds and final application that needs to be achieved; For example there exists different PVC grades such as coast or blow film, high impact, wire and cable grade, thermoforming, injection molding, rotational molding, etc. How is it produced Inexpensive, inert materials that simply add bulk to the plastic Characteristics of Polyvinyl Chloride These are some of the properties that makes PVC appropriate for several applications: - Toughness, strength.

- Ease of blending, ease of processing - Flame resistant and fire prevention properties For example PVC is difficult to ignite and in the absence of a powerful external flame will not continue to burn. This is due to its chlorine compound. This makes it an ideal construction and cable material. - It is compatible with other additives that can provide PVC clear or colored, rigid or flexible, etc.. - Excellent electrical insulation properties. This makes it ideal to be use in cables. - Impact strength and resistant to bad weather conditions (i.e. it does not corrode and is very durable), appropriate to be used as a construction material - Resistance to grease, oil and chemicals - PVC is chemically stable and does not de-polymerize - Density: 1.32-1.42 g/cc Environmental impact and occupational health and safety aspects of PVC Manufacture of PVC The manufacturing plastics often creates large quantities of toxic chemical pollutants such as dioxin, hydrochloric acid, and vinyl chloride. This poses a severe health risks to humans during the PVC life cycle. These toxins can produce sever illness like cancer, diabetes, neurological damage, reproductive and birth defects.

Dioxin is a persistent Organic Pollutants (POPs), this are chemical substances that persist in the environment, bio-accumulate through the food chain, and pose a risk of causing adverse effects to human health and the environment. In addition, the chloro-ethene monomer is also a carcinogen released during PVC manufacture. This un-reacted monomer can also be present in the final PVC and released during its life cycle. Plasticizers added to make PVC flexible, may leach out (ex. group phthalates) which are also toxic. Disposal Plastic was almost too good, as it was durable and degraded very slowly. On the other hand this same properties is what makes plastic a dangerous material. Due to the quantity and different additives added to PVC (the PVC product may consist up to 60% of additives) and also due to its chlorine contain, the final disposal or recycling of PVC is a issue to be closely examine. The options for disposal are recycling, landfill or incineration: - Recycling Thermoplastics can be remelted and reused, although the purity of the material tends to degrade with each reuse cycle. Furthermore, the separation of the different additives and compounds forming the plastic makes recycle a difficult option.

The biggest problem with plastics recycling is that it is difficult to automate the sorting of plastic waste, and so it is labor-intensive (ex. a mobile might have many different spare parts made out of different plastic materials). Thus because the value of the material is low, recycling plastics is unprofitable. Products such as automobiles are now being designed to make recycling of their large plastic parts easier. The international standard for defining environmental claims on products or packaging can be found in ISO 14021: Environmental Labels and Declarations-Self-declared Environmental Claims. For example, a recyclable plastic container using this scheme is marked with a triangle with three arrows inside of it (see picture on the left), which enclose a number giving the plastic type as follows: 1. PETE or PET (i.e. polyethylene terepthalate: termoplastic material used in plastic soft drink and rigid containers) 2. HDPE (i.e. high density polyethylene: the plastic commonly used to make milk and water jugs and two liter soda bottle bases) 3. PVC (i.e. polyvinyl chloride) 4. LDPE (i.e.

low density polyethylene: the plastic used in cellophane wrap, diaper liners, and some squeeze bottles) 5. PP (i.e. a light, thermoplastic resin used in packaging, coating, pipes, and tubes) 6. PS (i.e. polystyrene) The incineration of PVC causes the release of dioxins and other toxic chemicals. - Landfill Landfill of PVC has other environmental and social impacts. This is due to the not biodegradability of PVC which stays in place indefinitely; besides, attention should be taken to the fact that PVC may leach out toxic chemicals and contaminate the soil and water. There are some "biodegradable" plastics that break down with exposure to sunlight but it still doesn't lead to complete breakdown of the plastic. In addition, some researchers have genetically engineered bacteria that synthesize a completely biodegradable plastic. Market applications Construction material Due to PVC properties, as described above, around 50% of PVC (or vinyl) manufactured is used in construction replacing other materials such as wood or glass. Cheap, resistant, good weatherabiligy, ect. PVC is strong, lightweight, durable and versatile. These characteristics make it ideal for window profiles.

PVC's inherent flame retardant and excellent electrical insulation properties make it ideal for cabling applications. It can be used for flooring, windows and door frames and shutters, water and waste pipes, electrical applications such as cable and wire insulation materials, architectural glazing systems, wallpaper, etc. Medical devices PVC has been widely used for surgery, pharmaceuticals, drug delivery and medical packaging. Some products include blood bags, medical containers, fluid bags, tubing, heart and lung bypass sets, masks, gloves, bottles and jars, drainage systems, ducting, etc. The reasons to use it in the medical sector is its safety and chemical stability and bio-compatibility, chemical resistant and low cost. In addition, it is usable inside the body and easy to be sterilized. Automotive Typical examples of PVC automotive components include: moldings, interior door panels and pockets, seat coverings, sun visors, seals, floor covering, wiring, exterior side molding and protective strips, anti-stone damage protection, etc. Brakes Other applications PVC can be used for manufacturing toys, packaging, electric and electronic equipment, household goods, coating, plastic parts in motor vehicles, office supplies, insulation and adhesive tapes, furniture, etc.

For consumers in shoe soles, children's toys, handbags, luggage, seat coverings, etc. Industrial sectors for conveyor belts, printing rollers. Electric and electronic equipment such as circuit boards, cables, electrical boxes, computer housing. Material notes What is PVC? - PVC PVC Need something specific ? Use Search #if you are a robot type something# Property Modification of PVC Products What is PVC? Plastics are also called synthetic resins and are broadly classified into two categories: thermosetting resins and thermoplastic resins. The thermosetting resins include phenolic resin and melamine resin, which are thermally hardened and never become soft again. Thermoplastic resins include PVC, polyethylene (PE), polystyrene (PS) and polypropylene (PP), which can be re-softened by heating. Usually, thermoplastics are supplied in the form of pelletised material (compounds) with additives (antioxidants, etc.) already blended in it. However, PVC resin is often supplied in powder form and long term storage is possible since the material is resistant to oxidation and degradation. Various additives and pigments are added to PVC during the processing stage, and the blend is then converted into PVC products.

PVC is sometimes known as ‘Vinyl’ in Europe and predominantly so in North America. In Europe, ‘Vinyl’ usually refers to certain specific flexible applications, such as flooring, decorative sheets and artificial leather. PVC is a thermoplastic made of 57% chlorine (derived from industrial grade salt) and 43% carbon (derived predominantly from oil / gas via ethylene). It is less dependent than other polymers on crude oil or natural gas, which are nonrenewable, and hence can be regarded as a natural resource saving plastic, in contrast to plastics such as PE, PP, PET and PS, which are totally dependent on oil or gas. This chlorine gives to PVC excellent fire resistance. Related Info Chemicals in Plastics Home > Clear Science > Breast Cancer & Our Environment > Plastics Chemicals in Plastics Plastic is everywhere—it's used in consumer products and packaging of all kinds. And while it solves a lot of problems for manufacturers and can seem convenient to consumers, there are also serious risks to human health and the environment from its widespread use.

Three plastics have been shown to leach toxic chemicals when heated, worn or put under pressure: polycarbonate, which leaches bisphenol A ; polystyrene, which leaches styrene ; and PVC, or polyvinyl chloride, which break down into vinyl chloride and sometimes contains phthalates that can leach. And for more specific information about these and other chemicals found in plastics, including what they do and why they're bad for you, look below. Bisphenol A (BPA) TIPS FOR PREVENTION Even though plastic is everywhere, there's a lot you can do to reduce your use of the most toxic plastics. Tips for protecting your family from plastics > Bisphenol A (BPA) is one of the most pervasive chemicals in modern life. It's a building block of polycarbonate (#7 is often polycarbonate) plastic and is used in thousands of consumer products, including food packaging . BPA exposure may disrupt normal breast development in ways that predispose women for later life breast cancer. Phthalates Phthalates are a group of endocrine-disrupting chemicals found in PVC or #3 plastic.

Phthalate exposure has been linked to early puberty in girls, a risk factor for later-life breast cancer. Some phthalates also act as weak estrogens in cell culture systems. Vinyl Chloride Vinyl chloride is formed in the manufacture of polyvinyl chloride (PVC) or #3 plastic. It was one of the first chemicals designated as a known human carcinogen by the National Toxicology Program (NTP) and the International Agency for Research on Cancer (IARC). It has also been linked to increased mortality from breast cancer among workers involved in its manufacture. Dioxin Dioxin is formed in the manufacture of polyvinyl chloride (PVC) or #3 plastic. Dioxin has been classified by the International Agency for Research on Cancer (IARC) and the Environmental Protection Agency (EPA) as a known human carcinogen, and is also an endocrine disruptor . Styrene Styrene can leach from polystyrene or #6 plastic and is found in Styrofoam food trays, egg cartons, disposable cups and bowls, carryout containers and opaque plastic cutlery. It has been classified by the International Agency for Research on Cancer (IARC) as a possible human carcinogen.

Chemical of the Week -- Polymers POLYMERS Polymers are substances whose molecules have high molar masses and are composed of a large number of repeating units. There are both naturally occurring and synthetic polymers. Among naturally occurring polymers are proteins, starches, cellulose, and latex. Synthetic polymers are produced commercially on a very large scale and have a wide range of properties and uses. The materials commonly called plastics are all synthetic polymers. Polymers are formed by chemical reactions in which a large number of molecules called monomers are joined sequentially, forming a chain. In many polymers, only one monomer is used. In others, two or three different monomers may be combined. Polymers are classified by the characteristics of the reactions by which they are formed. If all atoms in the monomers are incorporated into the polymer, the polymer is called an addition polymer. If some of the atoms of the monomers are released into small molecules, such as water, the polymer is called a condensation polymer. Most addition polymers are made from monomers containing a double bond between carbon atoms. Such monomers are called olefins, and most commercial addition polymers are polyolefins.

Condensation polymers are made from monomers that have two different groups of atoms which can join together to form, for example, ester or amide links. Polyesters are an important class of commercial polymers, as are polyamides (nylon). POLYETHYLENE TEREPHTHALATE Polyethylene terephthalate (PET), or polyethylene terephthalic ester (PETE), is a condensation polymer produced from the monomers ethylene glycol, HOCH2CH2OH, a dialcohol, and dimethyl terephthalate, CH3O2CC6H4CO2CH3, a diester. By the process of transesterification, these monomers form ester linkages between them, yielding a polyester. PETE fibers are manufactured under the trade names of Dacron and Fortrel. Pleats and creases can be permanently heat set in fabrics containing polyester fibers, so-called permanent press fabrics. PETE can also be formed into transparent sheets and castings. Mylar is a trade name for a PETE film. Transparent 2-liter carbonated beverage bottles are made from PETE.

(The opaque base on some bottles is generally made of HDPE.) One form of PETE is the hardest known polymer and is used in eyeglass lenses. POLYETHYLENE Polyethylene is perhaps the simplest polymer, composed of chains of repeating CH2 units. It is produced by the addition polymerization of ethylene, CH2=CH2 (ethene). The properties of polyethylene depend on the manner in which ethylene is polymerized. When catalyzed by organometallic com pounds at moderate pressure (15 to 30 atm), the product is high density polyethylene, HDPE. Under these conditions, the polymer chains grow to very great length, and molar masses average many hundred thousands. HDPE is hard, tough, and resilient. Most HDPE is used in the manufacture of containers, such as milk bottles and laundry detergent jugs. When ethylene is polymerized at high pressure (10002000 atm), elevated temperatures (190210°C), and catalyzed by peroxides, the product is low density polyethylene, LDPE.

This form of polyethylene has molar masses of 20,000 to 40,000 grams. LDPE is relatively soft, and most of it is used in the production of plastic films, such as those used in sandwich bags. POLYVINYL CHLORIDE Polymerization of vinyl chloride, CH2=CHCl (chloroethene), produces a polymer similar to polyethylene, but having chlorine atoms at alternate carbon atoms on the chain. Polyvinyl chloride (PVC) is rigid and somewhat brittle. About two-thirds of the PVC produced annually is used in the manufacture of pipe. It is also used in the production of vinyl siding for houses and clear plastic bottles. When it is blended with a plasticizer such as a phthalate ester, PVC becomes pliable and is used to form flexible articles such as raincoats and shower curtains. POLYPROPYLENE This polymer is produced by the addition polymerization of propylene, CH2=CHCH3 (propene). Its molecular structure is similar to that of polyethylene, but has a methyl group (CH3) on alternate carbon atoms of the chain.

Its molar masses falls in the range 50,000 to 200,000 grams. Polypropylene (PP) is slightly more brittle than polyethylene, but softens at a temperature about 40°C higher. Polypropylene is used extensively in the automotive industry for interior trim, such as instrument panels, and in food packaging, such as yogurt containers. It is formed into fibers of very low absorbance and high stain resistance, used in clothing and home furnishings, especially carpeting. POLYSTYRENE Styrene, CH2=CHC6H5, polymerizes readily to form polystyrene (PS), a hard, highly transparent polymer. The molecular structure is similar to that of polypropylene, but with the methyl groups of polypropylene replaced by phenyl groups (C6H5). A large portion of production goes into packaging. The thin, rigid, transparent containers in which fresh foods, such as salads, are packaged are made from polystyrene. Polystyrene is readily foamed or formed into beads. These foams and beads are excellent thermal insulators and are used to produce home insulation and containers for hot foods.

Styrofoam is a trade name for foamed polystyrene. When rubber is dissolved in styrene before it is polymerized, the polystyrene produced is much more impact resistant. This type of polystyrene is used extensively in home appliances, such as the interior of refrigerators and air conditioner housing. [For more information about this polymer, see Chemical Demonstrations: A Handbook for Teachers of Chemistry, by Bassam Z. Shakhashiri, Volume 1 (1983), page 241.] POLYTETRAFLUOROETHYLENE Teflon is a trade name of polytetrafluoroethylene, PTFE. It is formed by the addition polymerization of tetrafluoroethylene, CF2=CF2 (tetrafluoroethene). PTFE is distinguished by its complete resistance to attack by virtually all chemicals and by its slippery surface. It maintains its physical properties over a large temperature range, -270° to 385°C. These properties make it especially useful for components that must operate under harsh chemical conditions and at temperature extremes. Its most familiar household use is as a coating on cooking utensils.

POLYURETHANE This important class of polymers is formed by the addition polymerization of an diisocyanate (whose molecules contain two NCO groups) and a dialcohol (two OH groups). The polymer chain is linked by urethane groups (OCONH). The NH portion of the urethane group can react similarly to an OH group, producing cross-linking between polymer chains. Polyurethane is spun into elastic fibers, called spandex, and sold under the trade name Lycra. Polyurethane can also be foamed. Soft polyurethane foams are used in upholstery, and hard foams are used structurally in light aircraft wings and sail boards. The formation of some polyurethane (and polystyrene) foams exploits the exothermic nature of the polymerization reaction. A liquid with a low boiling point, called a blowing agent, is added to the monomers before the polymerization starts. As the polymerization proceeds, it releases enough heat to boil the liquid. The boiling liquid produces bubbles that create a foam.

In the past, the most commonly used low-boiling liquids were chlorofluorocarbons. However, the damaging effect of chlorofluorocarbons on the stratospheric ozone layer has eliminated their use. Other low-boiling liquids have other disadvantages, such as flammability. Therefore, most polyurethane and polystyrene foams are manufactured by forcing a pressurized gas, such as nitrogen or carbon dioxide, into the polymerizing mixture. [For more information about this polymer, see Ibid., Volume 1, page 216.] POLYAMIDE Polyamides are a group of condensation polymers commonly known as nylon. Nylon is made from two monomers, one a dichloride and the other a diamine. One particular nylon is made from 1,6-diaminohexane, NH2(CH2)6NH2 and sebacoyl chloride, ClCO(CH2)8COCl. When these polymerize, the resulting molecules contain repeating units of NH(CH2)6NHCO(CH2)8CO. Molecules of HCl are released during the polymerization.

This particular polymer is called nylon 6-10 because it contains alternating chains of 6 and 10 carbon atoms between nitrogen atoms. Nylon can be readily formed into fibers that are strong and long wearing, making them well suited for use in carpeting, upholstery fabric, tire cords, brushes, and turf for athletic fields. Nylon is also formed into rods, bars, and sheets that are easily formed and machined. In this form, nylon is used for gears and for automobile fuel tanks. [For more information about this polymer, see Ibid., Volume 1, page 213.] POLYACRYLAMIDE Polyacrylamide is a condensation polymer with an unusual and useful property. The structure of polyacrylamide is similar to that of polyethylene, but having a hydrogen on every other carbon replace by an amide group, CONH2. The molecule is composed of repeating CH2CH(CONH2) units. The amide groups allow for linking between polymer strands. The CONH2 group from one molecule can react with the same group of another molecule, forming a link between them with the structure CONHCO.

This produces a network of polymer chains, rather like a tiny sponge. The free, unlinked amide groups, because they contain NH2 groups, can form hydrogen bonds with water. This gives the tiny cross linked sponges a great affinity for water. Polyacrylamide can absorb many times its mass in water. This property is useful in a variety of applications, such as in diapers and in potting soil. The polyacrylamide will release the absorbed water if a substance that interferes with hydrogen bonding is added. Ionic substances, such as salt, cause polyacrylamide to release its absorbed water. [For more information about this polymer, see Ibid., Volume 3 (1989), page 368.] City of Madison Plastic Recycling Guidelines Over the past few decades, the use of polymers in disposable consumer goods has grown tremendously. This growth is proving to be taxing on the waste disposal system, consuming a large fraction of available landfill space. Furthermore, the raw materials for these polymers are obtained from petroleum, a limited, non-renewable resource. To reduce the demand for landfill space and the consumption of limited petroleum reserves, the recycling of polymers has become a subject of concern.

One of the problems faced in recycling polymers is the great variety of polymers in use. To help sort wastes by type of polymer, most disposable polymeric goods are labeled with a recycling code: three arrows around a number above the polymer's acronym. These are intended to help consumers separate the waste polymers according to type before disposing of them. In the city of Madison, currently only type 1 (PETE) polymers are being recycled – see below. The recycling of polymers is not a closed loop, where a material is reformed into new products repeatedly, such as in the case with aluminum. Most polymeric materials are recycled only once, and the product made of recycled polymer is discarded after use. To obtain the maximum benefit from recycled polymer, the products made from it generally are intended to have a relatively long useful life. Recycled polymers are used in products such as cafeteria trays, large plastic toys, impact absorbing highway pylons, and carpeting. Some recycled PETE is now used in 2-liter soft-drink containers. In general, products made from recycled polymers are more expensive than those made from virgin plastic. This is the case because current manufacturing facilities are geared to production from new materials.

As more factories capable of using recycled plastics are constricted, the costs of using recycled polymers will decline; however, more factories will be built only if we are willing to pay "up front" the costs of recycling (as higher prices of consumer goods),rather than delaying costs of disposal (in the form of increased taxes) No product causes more confusion for users of the Madisonpride recycling program than plastic. Because plastic is expensive to collect and sort, recycling the wrong kinds of plastic is a waste of tax dollars. The Madisonpride recycling program accepts only those plastic containers marked . Remove and discard all lids or caps. Rinse all containers. Remove and discard sprayer tops. CRUSH all plastic bottles to save space. No 5 gallon pails. No containers with metal handles. What can be Recycled?

Question: How is the chemical compound Polyvinyl Chloride better known?
Answer: PVC