PlasticPlastic is a term that covers a range of synthetic or semisynthetic polymerization products. They are composed of organic condensation or addition polymers and may contain other substances to improve performance or economics. There are few natural polymers generally considered to be "plastics". Plastics can be formed into objects or films or fibers. Their name is derived from the fact that many are malleable, having the property of plasticity. Plastics are designed with immense variation in properties such as heat tolerance, hardness, resiliency and many others. Combined with this adaptability, the general uniformity of composition and light weight of plastics ensures their use in almost all industrial segments. Plastic may also refer to any material characterized by deformation or failure under shear stress; see plasticity and ductility. Plastic can be classified in many ways but most commonly by their polymer backbone (polyvinyl chloride, polyethylene, acrylic, silicone, urethane, etc.). Other classifications include thermoplastic vs. thermoset, elastomer, engineering plastic, addition or condensation, and Glass transition temperature or Tg. Many plastics are partially crystalline and partially amorphous in molecular structure, giving them both a melting point (the temperature at which the covalent bonds dissolve) and one or more glass transitions (temperatures at which the degree of cross-linking is substantially reduced). Plastics are polymers: long chains of atoms bonded to one another. These chains are made up of many repeating molecular units, or "monomers". The vast majority of plastics are composed of polymers of carbon alone or with oxygen, nitrogen, chlorine or sulfur in the backbone. (Some of commercial interest are silicon based.) The backbone is that part of the chain on the main "path" linking the multitude of monomer units together. To customize the properties of a plastic, different molecular groups "hang" from the backbone (usually they are "hung" as part of the monomers before linking monomers together to form the polymer chain). This customization by pendant groups has allowed plastics to become such an indispensable part of twenty first-century life by fine tuning the properties of the polymer. People experimented with plastics based on natural polymers for centuries. In the nineteenth century the discovered plastics based on chemically modified natural polymers: Charles Goodyear discovered vulcanization of rubber (1839) and Alexander Parkes discovered cellulose-based plastics in 1860s. The first plastic based on a synthetic polymer was called Bakelite and was created by Leo Hendrik Baekeland in 1907. The development of plastics has come from the use of natural materials (e.g., chewing gum, shellac) to the use of chemically modified natural materials (e.g., natural rubber, nitrocellulose) and finally to completely manmade molecules (e.g., epoxy, polyvinyl chloride, polyethylene). Natural polymersPeople have been using natural organic polymers for centuries in the form of waxes and shellacs. A plant polymer named "cellulose" provides the structural strength for natural fibers and ropes, and by the early 19th century natural rubber, tapped from rubber trees, was widespread use. Eventually, inventors learned to improve the properties of natural polymers. Natural rubber was sensitive to temperature, becoming sticky and smelly in hot weather and brittle in cold weather. In 1834, two inventors, Friedrich Ludersdorf of Germany and Nathaniel Hayward of the U.S., independently discovered that adding sulfur to raw rubber helped prevent the material from becoming sticky. In 1839, the American inventor Charles Goodyear was experimenting with the sulfur treatment of natural rubber when, according to legend, he dropped a piece of sulfur-treated rubber on a stove. The rubber seemed to have improved properties; Goodyear followed up with further experiments, and developed a process known as "vulcanization" that involved cooking the rubber with sulfur. Compared to untreated natural rubber, Goodyear's "vulcanized rubber" was stronger, more resistant to abrasion, more elastic, much less sensitive to temperature, impermeable to gases, and highly resistant to chemicals and electric current. Vulcanization remains an important industrial process for the manufacture of rubber in both natural and artificial forms. Natural rubber is composed of an organic polymer named "isoprene". Vulcanization creates sulfur bonds that link separate isoprene polymers together, improving the material's structural integrity and its other properties. Cellulose-based plastics: celluloid and rayonAll Goodyear had done with vulcanization was improve the properties of a natural polymer. The next logical step was to use a natural polymer, cellulose, as the basis for a new material. Inventors were particularly interested in developing synthetic substitutes for those natural materials that were expensive and in short supply, since that meant a profitable market to exploit. Ivory was a particularly attractive target for a synthetic replacement. An Englishman from Birmingham named Alexander Parkes developed a "synthetic ivory" named "pyroxlin", which he marketed under the trade name "Parkesine", and which won a bronze medal at the 1862 World's fair in London. Parkesine was made from cellulose treated with nitric acid and a solvent. The output of the process hardened into a hard, ivory-like material that could be molded when heated. However, Parkes was not able to scale up the process to an industrial level, and products made from Parkesine quickly warped and cracked after a short period of use. An American printer and amateur inventor named John Wesley Hyatt took up where Parkes left off. Parkes had failed for lack of a proper softener, but Hyatt discovered that camphor would do the job very nicely. Hyatt was something of an industrial genius who understood what could be done with such a shapeable, or "plastic", material, and proceeded to design much of the basic industrial machinery needed to produce good-quality plastic materials in quantity. Since cellulose was the main constituent used in the synthesis of his new material, Hyatt named it "celluloid". It was introduced in 1863. One of the first products were dental pieces, and sets of false teeth built around celluloid proved cheaper than existing rubber dentures. However, celluloid dentures tended to soften when hot, making tea drinking tricky, and the camphor taste tended to be difficult to suppress. Celluloid's real breakthrough products were waterproof shirt collars, cuffs, and the false shirtfronts known as "dickies", whose unmanageable nature later became a stock joke in silent-movie comedies. They did not wilt and did not stain easily, and Hyatt sold them by trainloads. Corsets made with celluloid stays also proved popular, since perspiration did not rust the stays, as it would if they had been made of metal. Celluloid proved extremely versatile in its field of application, providing a cheap and attractive replacement for ivory, tortoiseshell, and bone, and traditional products that had used these materials were much easier to fabricate with plastics. Some of the items made with cellulose in the nineteenth century were beautifully designed and implemented. For example, celluloid combs made to tie up the long tresses of hair fashionable at the time are now jewellike museum pieces. Such pretty trinkets were no longer only for the rich. Celluloid could also be used in entirely new applications. Hyatt figured out how to fabricate the material in a strip format for movie film. By the year 1900, movie film was a major market for celluloid. However, celluloid still tended to yellow and crack over time, and it had another more dangerous defect: it burned very easily and spectacularly, unsurprising given that mixtures of nitric acid and cellulose are also used to synthesize smokeless powder. Ping-pong balls, one of the few products still made with celluloid, sizzle and burn if set on fire, and Hyatt liked to tell stories about celluloid billiard balls exploding when struck very hard. These stories might have had a basis in fact, since the billiard balls were often celluloid covered with paints based on another, even more flammable, nitrocellulose product known as "collodion". If the balls had been imperfectly manufactured, the paints might have acted as primer to set the rest of the ball off with a bang. Cellulose was also used to produce cloth. While the men who developed celluloid were interested in replacing ivory, those who developed the new fibers were interested in replacing another expensive material, silk. In 1884, a French chemist, the Comte de Chardonnay, introduced a cellulose-based fabric that became known as "Chardonnay silk". It was an attractive cloth, but like celluloid it was very flammable, a property completely unacceptable in clothing. After some ghastly accidents, Chardonnay silk was taken off the market. In 1894, three British inventors, Charles Cross, Edward Bevan, and Clayton Beadle, patented a new "artificial silk" or "art silk" that was much safer. The three men sold the rights for the new fabric to the French Courtauld company, a major manufacturer of silk, which put it into production in 1905, using cellulose from wood pulp as the "feedstock" material. Art silk became well known under the trade name "rayon", and was produced in great quantities through the 1930s, when it was supplanted by better artificial fabrics. It still remains in production today, often in blends with other natural and artificial fibers. It is cheap and feels smooth on the skin, though it is weak when wet and creases easily. It could also be produced in a transparent sheet form known as "cellophane". Bakelite (phenolic)The limitations of celluloid led to the next major advance, known as "phenolic" or "phenol-formaldehyde" plastics. A chemist named Leo Hendrik Baekeland, a Belgian-born American living in New York state, was searching for an insulating shellac to coat wires in electric motors and generators. Baekeland found that mixtures of phenol (C6H5OH) and formaldehyde (HCOH) formed a sticky mass when mixed together and heated, and the mass became extremely hard if allowed to cool and dry. He continued his investigations and found that the material could be mixed with wood flour, asbestos, or slate dust to create "composite" materials with different properties. Most of these compositions were strong and fire resistant. The only problem was that the material tended to foam during synthesis, and the resulting product was of unacceptable quality. Baekeland built pressure vessels to force out the bubbles and provide a smooth, uniform product. He publicly announced his discovery in 1909, naming it "bakelite". It was originally used for electrical and mechanical parts, finally coming into widespread use in consumer goods in the 1920s. When the Bakelite patent expired in 1927, the Catalin Corporation acquired the patent and began manufacturing Catalin plastic using a different process that allowed a wider range of coloring. Bakelite was the first true plastic. It was a purely synthetic material, not based on any material or even molecule found in nature. It was also the first "thermoset" plastic. Conventional "thermoplastics" can be molded and then melted again, but thermoset plastics form bonds between polymers strands when "cured", creating a tangled matrix that cannot be undone without destroying the plastic. Thermoset plastics are tough and temperature resistant. Bakelite was cheap, strong, and durable. It was molded into thousands of forms, such as radios, telephones, clocks, and, of course, billiard balls. The U.S. government even considered making one-cent coins out of it when World War II caused a copper shortage. Phenolic plastics have been largely replaced by cheaper and less brittle plastics, but they are still used in applications requiring its insulating and heat-resistant properties. For example, some electronic circuit boards are made of sheets of paper or cloth impregnated with phenolic resin. Polystyrene and PVCAfter the First World War, improvements in chemical technology led to an explosion in new forms of plastics. Among the earliest examples in the wave of new plastics were "polystyrene" (PS) and "polyvinyl chloride" (PVC), developed by IG Farben of Germany. Polystyrene is a rigid, brittle plastic that is now used to make plastic model kits, disposable eating utensils, and similar knickknacks. It would also be the basis for one of the most popular "foamed" plastics, under the name "styrene foam" or "Styrofoam". Foam plastics can be synthesized in an "open cell" form, in which the foam bubbles are interconnected, as in an absorbent sponge, and "closed cell", in which all the bubbles are distinct, like tiny balloons, as in gas-filled foam insulation and floatation devices. H H H H H H / | | | | C==C -> -- C -- C -- C -- C -- / | | | | H R R H R H styrene monomer polystyrene polymer (R is a phenyl (benzene) group) PVC has side chains incorporating chlorine atoms, which form strong bonds. PVC in its normal form is stiff, strong, heat and weather resistant, and is now used for making plumbing, gutters, house siding, enclosures for computers and other electronics gear. PVC can also be softened with chemical processing, and in this form it is now used for shrink-wrap, food packaging, and raingear. H H H H H H / | | | | C==C -> -- C -- C -- C -- C -- / | | | | H Cl H Cl H Cl vinyl chloride monomer polyvinyl chloride polymer NylonThe real star of the plastics industry in the 1930s was "polyamide" (PA), far better known by its trade name, "nylon". Nylon was the first purely synthetic fiber, introduced by Du Pont Corporation at the 1939 World's Fair in New York City. In 1927, Du Pont had begun a secret development project designated "Fiber66", under the direction of a Harvard chemists Wallace Carothers and Chemistry Department director E.K. Bolton. Carothers had been hired to perform pure research, and not only investigated new materials, but worked to understand their molecular structure and how it related to material properties. He took some of the first steps on the road to "molecular design" of materials. His work led to the discovery of synthetic nylon fiber, which was very strong but also very flexible. The first application was for bristles for toothbrushes. However, Du Pont's real target was silk, particularly silk stockings. General condensation polymerization reaction for nylonIt took Du Pont twelve years and US$27 million to refine nylon and develop the industrial processes for bulk manufacture. With such a major investment, it was no surprise that Du Pont spared little expense to promote nylon after its introduction, creating a public sensation, or "nylon mania". Nylon mania came to an abrupt stop at the end of 1941 when the USA entered World War II. The production capacity that had been built up to produce nylon stockings, or just "nylons", for American women was taken over to manufacture vast numbers of parachutes for fliers and paratroopers. After the war ended, Du Pont went back to selling nylon to the public, engaging in another promotional campaign in 1946 that resulted in an even bigger craze, triggering off "nylon riots". Nylon still remains an important plastic, and not just for use in fabrics. In its bulk form it is very wear resistant, and so is used to build gears, bearings, bushings, and other mechanical parts. Synthetic rubberAnother plastic that was critical to the war effort was "synthetic rubber", which was produced in a variety of forms. The first synthetic rubber polymer was obtained by Lebedev in 1910. Practical synthetic rubber grew out of studies published in 1930 written independently by American Wallace Carothers, Russian scientist Lebedev and the German scientist Hermann Staudinger. These studies led in 1931 to one of the first successful synthetic rubbers, known as "neoprene", which was developed at DuPont under the direction of E.K. Bolton. Neoprene is highly resistant to heat and chemicals such as oil and gasoline, and is used in fuel hoses and as an insulating material in machinery. In 1935, German chemists synthesized the first of a series of synthetic rubbers known as "Buna rubbers". These were "copolymers", meaning that their polymers were made up from not one but two monomers, in alternating sequence. One such Buna rubber, known as "GR-S" ("Government Rubber Styrene), is a copolymer of butadiene and styrene, became the basis for U.S. synthetic rubber production during World War II. Worldwide natural rubber supplies were limited, and by mid-1942 most of the rubber-producing regions were under Japanese control. Military trucks needed rubber for tires, and rubber was used in almost every other war machine. The U.S. government launched a major (and largely secret) effort to develop and refine synthetic rubber. A principal scientist involved with the effort was Edward Robbins. By 1944 a total of 50 factories were manufacturing it, pouring out a volume of the material twice that of the world's natural rubber production before the beginning of the war. After the war, natural rubber plantations no longer had a stranglehold on rubber supplies, particularly after chemists learned to synthesize isoprene. GR-S remains the primary synthetic rubber for the manufacture of tires. Synthetic rubber would also play an important part in the space race and nuclear arms race. Solid rockets used during World War II used nitrocellulose explosives for propellants, but it was impractical and dangerous to make such rockets very big. During the war, California Institute of Technology (Caltech) researchers came up with a new solid fuel, based on asphalt fuel mixed with an oxidizer, such as potassium or ammonium percholorate, plus aluminium powder, which burns very hot. This new solid fuel burned more slowly and evenly than nitrocellulose explosives, and was much less dangerous to store and use, though it tended to flow slowly out of the rocket in storage and the rockets using it had to be stockpiled nose down. After the war, the Caltech researchers began to investigate the use of synthetic rubbers instead of asphalt as the fuel in the mixture. By the mid-1950s, large missiles were being built using solid fuels based on synthetic rubber, mixed with ammonium perchlorate and high proportions of aluminium powder. Such solid fuels could be cast into large, uniform blocks that had no cracks or other defects that would cause nonuniform burning. Ultimately, all large military rockets and missiles would use synthetic rubber based solid fuels, and they would also play a significant part in the civilian space effort. Plastics explosion: acrylic, polyethylene, etc.Other plastics emerged in the prewar period, though some would not come into widespread use until after the war. By 1936, American, British, and German companies were producing polymethyl methacrylate (PMMA), better known as "acrylic". Although acrylics are now well known for their use in paints and synthetic fibers, such as "fake furs", in their bulk form they are actually very hard and more transparent than glass, and are sold as glass replacements under trade names such as "Plexiglas" and "Lucite". Plexiglas was used to build aircraft canopies during the war, and it is also now used as a marble replacement for countertops. Another important plastic, "polyethylene" (PE), sometimes known as "polythene", was discovered in 1933 by Reginald Gibson and Eric Fawcett at the British industrial giant Imperial Chemical Industries (ICI). This material evolved into two forms, "low density polyethylene" (LDPE), and "high density polyethylene" (HDPE). H H H H H / | | | C==C -> -- C -- C -- C -- / | | | H H H H H ethylene monomer polyethylene polymer
Polyethylene would lead after the war to an improved material, "polypropylene" (PP), which was discovered in the early 1950s by Giulio Natta. It is common in modern science and technology that the growth of the general body of knowledge can lead to the same inventions in different places at about the same time, but polypropylene was an extreme case of this phenomenon, being separately invented about nine times. It was a patent attorney's dream scenario, and litigation was not resolved until 1989. Polypropylene managed to survive the legal process, and two American chemists working for Phillips Petroleum, J. Paul Hogan and Robert Banks, are now generally credited as the "official" inventors of the material. Polypropylene is similar to its ancestor, polyethylene, and shares polyethylene's low cost, but it is much more robust. It is used in everything from plastic bottles to carpets to plastic furniture, and is very heavily used in automobiles. CH3 H CH3 H CH3 H / | | | | C==C -> -- C -- C -- C -- C -- / | | | | H H H H H H propylene monomer polypropylene polymer
In 1939, IG Farben filed a patent for "polyepoxide" or "epoxy". Epoxies are a class of thermoset plastic that form cross-links and "cure" when a catalyzing agent, or "hardener", is added. After the war they would come into wide use for coatings, "adhesives", and composite materials. Composites using epoxy as a matrix include glass-reinforced plastic, where the structural element is glass fiber, and "carbon-epoxy composites", in which the structural element is carbon fiber. Fiberglass is now often used to build sport boats, and carbon-epoxy composites are an increasingly important structural element in aircraft, as they are lightweight, strong, and heat resistant. Two chemists named Rex Whinfield and James Dickson, working at a small English company with the quaint name of the "Calico Printer's Association" in Manchester, developed "polyethylene terephthalate" (PET or PETE) in 1941, and it would be used for synthetic fibers in the postwar era, with names such as "polyester", "dacron", and "terylene". PET is more impermeable than other low-cost plastics and so is a popular material for making bottles for Coca-Cola and other "fizzy drinks", since carbonation tends to attack other plastics, and for acidic drinks such as fruit or vegetable juices. PET is also strong and abrasion resistant, and is used for making mechanical parts, food trays, and other items that have to endure abuse. PET films, trade named "Mylar®", are used to make recording tape. One of the most impressive plastics used in the war, and a top secret, was "polytetrafluoroethylene" (PTFE), better known as "Teflon", which could be deposited on metal surfaces as a scratchproof and corrosion-resistant, low-friction protective coating. The polyfluoroethylene surface layer created by exposing a polyethylene container to fluorine gas is very similar to Teflon. A Du Pont chemist named Roy Plunkett discovered Teflon by accident in 1938. During the war, it was used in gaseous-diffusion processes to refine uranium for the atomic bomb, as the process was highly corrosive. By the early 1960s, Teflon "nonstick" frying pans were a hot consumer item. F F F F F / | | | C==C -> -- C -- C -- C -- / | | | F F F F F tetrafluoroethylene monomer teflon polymer
After the war, the new plastics that had been developed entered the consumer mainstream in a flood. New manufacturing were developed, using various forming, molding, casting, and extrusion processes, to churn out plastic products in vast quantities. American consumers enthusiastically adopted the endless range of colorful, cheap, and durable plastic gimmicks being produced for new suburban home life. One of the most visible parts of this plastics invasion was Earl Tupper's "Tupperware", a complete line of sealable polyethylene food containers that Tupper cleverly promoted through a network of housewives who sold Tupperware as a means of bringing in some money. The Tupperware line of products was well thought out and highly effective, greatly reducing spoilage of foods in storage. Thin-film "plastic wrap" that could be purchased in rolls also helped keep food fresh. Another prominent element in 1950s homes was "Formica®", a plastic laminate that was used to surface furniture and cabinetry. Formica was durable and attractive. It was particularly useful in kitchens, as it did not absorb, and could be easily cleaned of stains from food preparation, such as blood or grease. With Formica, a very attractive and well-built table could be built using low-cost and lightweight plywood with Formica covering, rather than expensive and heavy hardwoods like oak or mahogany. Composite materials like fiberglass came into use for building boats and, in some cases, cars. Polyurethane foam was used to fill mattresses, and Styrofoam was used to line ice coolers and make float toys. Plastics continue to be improved. General Electric introduced "lexan", a high-impact "polycarbonate" plastic, in the 1970s. Du Pont developed "Kevlar", an extremely strong synthetic fiber that was best known for its use in bullet-proof vests and combat helmets. Kevlar was so remarkable that Du Pont officials actually had to release statements to deny rumors that the company had received the recipe for it from space aliens. The environmentAlthough plastics have had a remarkable impact globally, it has become increasingly obvious that there is a price to be paid for their use. Plastics are almost too good, as they are durable and degrade very slowly. In some cases, burning plastic can release toxic fumes. Also, the manufacturing of plastics often creates large quantities of chemical pollutants, and requires use of the Earth's limited supply of fossil fuels. However, it should be noted that plastics only consume 4% of the world's oil production. Furthermore, it can be claimed that the use of plastics helps the environment by saving water and oil. For example, plastics make cars lighter, thus saving oil and reducing CO2 emissions. By the 1990s, plastic recycling programs were common in the United States and elsewhere. Thermoplastics can be remelted and reused, and thermoset plastics can be ground up and used as filler, though the purity of the material tends to degrade with each reuse cycle. There are methods by which plastics can be broken back down to a feedstock state. To assist recycling of disposable items, the Plastic Bottle Institute of the Society of the Plastics Industry devised a now-familiar scheme to mark plastic bottles by plastic type. A recyclable plastic container using this scheme is marked with a triangle of three "chasing arrows", which enclose a number giving the plastic type: Plastics type marks: the resin identification code
Unfortunately, recycling plastics has proven difficult. The biggest problem with plastics recycling is that it is difficult to automate the sorting of plastic waste, and so it is labor intensive. Typically, workers sort the plastic by looking at the resin identification code, though common containers like soda bottles can be sorted from memory. Other recyclable materials, such as metals, are easier to process mechanically. While containers are usually made from a single type and color of plastic, making them relatively easy to sort out, a consumer product like a cellular phone may have many small parts consisting of over a dozen different types and colors of plastics. In a case like this, the resources it would take to separate the plastics far exceed their value, though complex items made of many types of plastics are not disposed of frequently. Recycling certain types of plastics can be unprofitable, as well. For example, polystyrene is rarely recycled because it is usually not cost effective. These unrecyclable wastes can be disposed of in landfills, incinerated or used to produce electricity at waste-to-energy plants. Currently, the percentage of plastics recycled in the U.S. is very small, somewhere around 5%. Even so the American Plastics Council spends about US$20 million a year on an ad campaign that tries to convince the public to recycle. Biodegradable PlasticsResearch has been done on biodegradable plastics that break down with exposure to sunlight. Starch can be mixed with plastic to allow it to degrade more easily, but it still does not lead to complete breakdown of the plastic. Some researchers have actually genetically engineered bacteria that synthesize a completely biodegradable plastic, but this material is expensive at present. BASF make Ecoflex, a fully biodegradable polyester for food packaging applications. The disadvantage of biodegradable plastics is that the carbon that is locked up in them is released into the atmosphere as the greenhouse gas carbon dioxide when they degrade, though if they are made from organic material there is no net gain in emissions. So far, these plastics have proven too costly and limited for general use, and critics have pointed out that the only real problem they address is roadside litter, which is regarded as a secondary issue. When such plastic materials are dumped into landfills, they can become "mummified" and persist for decades even if they are supposed to be biodegradable. In this regard, though, plastics are no worse than food or paper, which also fail to degrade in landfills. There have been some success stories. The Courtauld concern, the original producer of rayon, came up with a revised process for the material in the mid-1980s to produce "Tencel". Tencel has many superior properties over rayon, but is still produced from "biomass" feedstocks, and its manufacture is extraordinarily clean by the standards of plastic production. Price and the futureOne of the great appeals of plastics have been their low price as compared to other materials. However, in recent years the cost of plastics has been rising dramatically. The cause of the increase is the sharply rising cost of petroleum, the raw material that is chemically altered to form commercial plastics. As the cost of plastic hinges on the cost of petroleum, should petroleum prices continue to rise, so will the cost of plastic. In 2004, the higher price of plastic drove a number of plastic-toy manufacturers out of business. Fears of dwindling petroleum supplies are becoming very real, with publications such as USA Today reporting that current oil reserves will only last 40 years. Alternate reserves such as oil shale and tar oil (tar sand) do exist, but the cost of production is much higher than with current sources. Thus, even if alternative sources are used, costs will continue to rise. Scientists are seeking cheaper alternatives to plastic. Some plastic alternatives are: graphite, fiberglass, carbon fiber, graphene, carbon nanotubes, diamond, aerogel, carbon nanofoam, cellulose soybean plastic (bioplastic), and other carbon-based, non-petroleum materials. Some of these alternatives are too expensive or not malleable enough, but can be used in some plastic applications. Some are many times stronger than plastic, but crack if made thin like cellophane. The most promising alternatives to plastic are graphene, carbon nanotube, and carbon nanofoam. All three of these are made of nanocarbons, products of the new nanotechnology. Nanocarbons are very cheap, 100 times stronger than steel, slicker than Teflon, lightweight, and can be made very thin, made to stretch, and built into any shape—all the things plastic can do. In addition, nanocarbon manufacturing is low to nonpolluting. Already, bowling balls, golf balls, sports equipment, and waterproof cotton balls have been made of nanocarbons. Common plastics and their typical uses
Special purpose plastics
This page about Plastic includes information from a Wikipedia article. Additional articles about Plastic News stories about Plastic External links for Plastic Videos for Plastic Wikis about Plastic Discussion Groups about Plastic Blogs about Plastic Images of Plastic |
|
Already, bowling balls, golf balls, sports equipment, and waterproof cotton balls have been made of nanocarbons. See List of Power Rangers characters for more extensive listings. In addition, nanocarbon manufacturing is low to nonpolluting. Rangers | Villains | Enemy Grunts | Monsters |. Nanocarbons are very cheap, 100 times stronger than steel, slicker than Teflon, lightweight, and can be made very thin, made to stretch, and built into any shape—all the things plastic can do. The current Power Rangers DVD titles are:. All three of these are made of nanocarbons, products of the new nanotechnology. The ongoing concern over Power Rangers as a whole not being released on DVD Box sets has led to continued debate and frequent petitions. The most promising alternatives to plastic are graphene, carbon nanotube, and carbon nanofoam. There has been much criticism over the releases of these DVDs; only five volumes per season are distributed, which does not amount to the full length run, and so viewers have to rely on reruns to see any other episodes not currently available. Some are many times stronger than plastic, but crack if made thin like cellophane. Buena Vista Home Entertainment is scheduled to release five new volumes of the upcoming season, Power Rangers: Mystic Force in 2006. Some of these alternatives are too expensive or not malleable enough, but can be used in some plastic applications. Internationally, however there have been additional DVD releases (such as Time Force and Wild Force in Germany) and as free DVDs attached to Jetix Magazine UK. Some plastic alternatives are: graphite, fiberglass, carbon fiber, graphene, carbon nanotubes, diamond, aerogel, carbon nanofoam, cellulose soybean plastic (bioplastic), and other carbon-based, non-petroleum materials. Currently, there are only 18 DVD releases of Power Rangers in the USA (as listed below). Scientists are seeking cheaper alternatives to plastic. Contrary to wild Internet speculation, there have never been plans for a third Power Rangers movie. Thus, even if alternative sources are used, costs will continue to rise. The Power Rangers series have also brought forth two movies. Alternate reserves such as oil shale and tar oil (tar sand) do exist, but the cost of production is much higher than with current sources. This fad-like popularization of martial arts in mainstream youth culture is often looked at as one of the reasons the McDojo has become somewhat of a prevalent phenomenon. Fears of dwindling petroleum supplies are becoming very real, with publications such as USA Today reporting that current oil reserves will only last 40 years. Many also credit Power Rangers for an increased interest in the martial arts by suburban America. In 2004, the higher price of plastic drove a number of plastic-toy manufacturers out of business. It would also cause them to lose revenue in toy and merchandising sales, which finance the shows. As the cost of plastic hinges on the cost of petroleum, should petroleum prices continue to rise, so will the cost of plastic. However, whereas Power Rangers still appeals to older viewers, the show's producers feel that a more mature show might alienate their largest demographic—children. The cause of the increase is the sharply rising cost of petroleum, the raw material that is chemically altered to form commercial plastics. This has led to some fans requesting that the tone and format of the show be changed in order to better suit its more mature audience. However, in recent years the cost of plastics has been rising dramatically. However, since its release, the show has continued to evolve into a program that is enjoyed by more mature audiences, partly due to its aging original fans. One of the great appeals of plastics have been their low price as compared to other materials. When Power Rangers was first released it was classified as children's programming. Tencel has many superior properties over rayon, but is still produced from "biomass" feedstocks, and its manufacture is extraordinarily clean by the standards of plastic production. However, Jetix in its British incarnation still issues a generic warning for the entire series that was used since the beginning of Power Rangers: In Space. The Courtauld concern, the original producer of rayon, came up with a revised process for the material in the mid-1980s to produce "Tencel". As a result, GMTV (who is still the analogue host in the UK) had to issue a warning at the end of an episode stating, "The Power Rangers are specially trained martial arts experts, so don't you copy them!" GMTV no longer issues this warning. There have been some success stories. In the UK, the first incarnation sparked fears that kids would hurt themselves by recreating the moves in the series. In this regard, though, plastics are no worse than food or paper, which also fail to degrade in landfills. Team-ups between a current cast and the one before it occur almost annually now, but are generally superfluous to the larger storylines and are sometimes even considered out of continuity. When such plastic materials are dumped into landfills, they can become "mummified" and persist for decades even if they are supposed to be biodegradable. Subsequent series are able to start with new Rangers and villains annually without having to incorporate unresolved plot points from the previous season. So far, these plastics have proven too costly and limited for general use, and critics have pointed out that the only real problem they address is roadside litter, which is regarded as a secondary issue. Space's finale, "Countdown to Destruction," acted as Power Rangers' version of Crisis on Infinite Earths, killing off or redeeming all of the older villains and largely cleaning up the existing continuity. The disadvantage of biodegradable plastics is that the carbon that is locked up in them is released into the atmosphere as the greenhouse gas carbon dioxide when they degrade, though if they are made from organic material there is no net gain in emissions. Veteran Rangers and villains also occasionally appeared after their stories had run through, most notably in Power Rangers: In Space, in which the central plot involved an attack on the entire universe. BASF make Ecoflex, a fully biodegradable polyester for food packaging applications. The first five years of the series featured ongoing storylines that carried through the different seasons, and retained most of its castmembers for several years. Some researchers have actually genetically engineered bacteria that synthesize a completely biodegradable plastic, but this material is expensive at present. The few-and-far-between links between the later series of Power Rangers are often resented by older fans of the show. Starch can be mixed with plastic to allow it to degrade more easily, but it still does not lead to complete breakdown of the plastic. Since then, no Asian-American actor or actress has played the Yellow Ranger, and no African-American has played the Black Ranger. Research has been done on biodegradable plastics that break down with exposure to sunlight. Amy Jo Johnson and Walter Emmanuel Jones appeared in the "1993" episode. Even so the American Plastics Council spends about US$20 million a year on an ad campaign that tries to convince the public to recycle. This was mentioned on VH1's I Love the 90s. is very small, somewhere around 5%. This criticism was rendered moot when the two actors left the show halfway through Season Two and were replaced with an Asian American male as the Black Ranger, and an African American woman as the Yellow Ranger. Currently, the percentage of plastics recycled in the U.S. The first season of Power Rangers also drew criticism from some groups claiming that the Ranger colors were racist, specifically referring to Zack, the Black Ranger (played by African American actor Walter Emmanuel Jones) and Trini, the Yellow Ranger (played by Asian American actress Thuy Trang). These unrecyclable wastes can be disposed of in landfills, incinerated or used to produce electricity at waste-to-energy plants. For a time Power Rangers was pulled from Malaysian television screens as the word "morphin" (in the phrase "It's Morphin Time!") sounded similar to the drug morphine, which is banned in Malaysia. For example, polystyrene is rarely recycled because it is usually not cost effective. Norway pulled the series as they believed that the series caused two boys to beat up a girl in 1993 (it was eventually found that the murder was unconnected to the series). Recycling certain types of plastics can be unprofitable, as well. Later incarnations of Power Rangers often attempt to explain the actions of the Power Rangers, but many still believe that Power Rangers remains a series too violent for young children. In a case like this, the resources it would take to separate the plastics far exceed their value, though complex items made of many types of plastics are not disposed of frequently. In some cases, networks pulled Power Rangers from its lineup, citing such concerns. While containers are usually made from a single type and color of plastic, making them relatively easy to sort out, a consumer product like a cellular phone may have many small parts consisting of over a dozen different types and colors of plastics. Many critics of the early Power Rangers series claimed that the Power Rangers use unnecessary force to destroy their monsters, and often get into fights when better alternatives were available. Other recyclable materials, such as metals, are easier to process mechanically. They were immediately replaced, to a negative effect on the show's ratings. Typically, workers sort the plastic by looking at the resin identification code, though common containers like soda bottles can be sorted from memory. John, Walter Emmanuel Jones and Thuy Trang left the series when none of their demands were met. The biggest problem with plastics recycling is that it is difficult to automate the sorting of plastic waste, and so it is labor intensive. When the series hit big time, Fox signed the show to a two-picture deal, and actors Austin St. Unfortunately, recycling plastics has proven difficult. The "Mighty Morphin" cast was bound to five-year contracts with no benefits and insultingly low pay (reportedly $500 US per week), which were non-negotiable. A recyclable plastic container using this scheme is marked with a triangle of three "chasing arrows", which enclose a number giving the plastic type:. Original Executive Producer Haim Saban was criticized heavily for his use of non-SAG actors, and the one-sided contracts that the actors were bound to for appearing on the show. To assist recycling of disposable items, the Plastic Bottle Institute of the Society of the Plastics Industry devised a now-familiar scheme to mark plastic bottles by plastic type. In Power Rangers: Wild Force, the tenth incarnation of Power Rangers, this is taken to the next level, as ten Red Rangers teamed up in the episode "Forever Red." The only season not to feature this is Power Rangers: Ninja Storm, due to a shift back to non-SAG talent when production was moved to New Zealand. There are methods by which plastics can be broken back down to a feedstock state. A tradition in later incarnations is for two teams of Power Rangers to team up and take on a villain. Thermoplastics can be remelted and reused, and thermoset plastics can be ground up and used as filler, though the purity of the material tends to degrade with each reuse cycle. In incarnations following Power Rangers: In Space, it is common for each incarnation to be separate, storywise, from previous incarnations. By the 1990s, plastic recycling programs were common in the United States and elsewhere. Although much of the arsenal can also be found in Super Sentai, there are usually at least some that are not, generally added for the express purpose of marketing toys designed and sold by Bandai. For example, plastics make cars lighter, thus saving oil and reducing CO2 emissions. In some cases one Ranger may receive something that other Rangers may not have; an example of this is the Battlizer given to the Red Ranger of each series since Power Rangers: In Space. Furthermore, it can be claimed that the use of plastics helps the environment by saving water and oil. In many series, a Ranger is also given additional Zords or weapons. However, it should be noted that plastics only consume 4% of the world's oil production. As the series progresses, one or more of the Rangers are also usually given a motorcycle for long-distance travel, as well as individual Zords. Also, the manufacturing of plastics often creates large quantities of chemical pollutants, and requires use of the Earth's limited supply of fossil fuels. Each Ranger also has a secondary set of weapons that can often combine to form a larger weapon (usually a cannon). In some cases, burning plastic can release toxic fumes. The arsenal available to the Power Rangers is also somewhat standardized: each Ranger is generally armed with a weapon such as a laser gun or a sword. Plastics are almost too good, as they are durable and degrade very slowly. The penalty for disobeying these rules, at least in Mighty Morphin Power Rangers, would be the loss of their power. Although plastics have had a remarkable impact globally, it has become increasingly obvious that there is a price to be paid for their use. The Power Rangers are also forbidden to disclose their identities to the general public, barring extenuating circumstances (although this rule was disregarded in Power Rangers: Lightspeed Rescue and Power Rangers: SPD). Kevlar was so remarkable that Du Pont officials actually had to release statements to deny rumors that the company had received the recipe for it from space aliens. These include the Power Rangers being forbidden to use their Ranger powers for personal gain or for escalating a fight, explaining why the Rangers don't just step on the small monsters with their Megazord. Du Pont developed "Kevlar", an extremely strong synthetic fiber that was best known for its use in bullet-proof vests and combat helmets. Each team of Power Rangers, with few exceptions, obey a general set of conventions, outlined at the beginning of Mighty Morphin Power Rangers and implied, though not stated explicitly, throughout many of the other incarnations. General Electric introduced "lexan", a high-impact "polycarbonate" plastic, in the 1970s. The plot sequence is generally as follows:. Plastics continue to be improved. A normal Power Rangers episode can be broken down into an everyplot. Polyurethane foam was used to fill mattresses, and Styrofoam was used to line ice coolers and make float toys. The team's costumes are nearly identical aside from color and perhaps a number designation; any additional Rangers will regularly have additional costume modifications. Composite materials like fiberglass came into use for building boats and, in some cases, cars. There is usually no more than one Ranger of a given color on a team, but exceptions of this rule are generally given alternate names. With Formica, a very attractive and well-built table could be built using low-cost and lightweight plywood with Formica covering, rather than expensive and heavy hardwoods like oak or mahogany. Rangers may be named after their respective colors, such as Red Ranger, Blue Ranger, etc., but numbers or other names may also be used. It was particularly useful in kitchens, as it did not absorb, and could be easily cleaned of stains from food preparation, such as blood or grease. Each Ranger's suit and energy spectrum will match a specific color, with red, yellow, and blue being joined by some combination of pink, green, black, or white. Formica was durable and attractive. Rangers regularly operate in teams of five, with a special sixth Ranger frequently rounding out the bunch; sometimes a core team of three will later be joined by additional Rangers. Another prominent element in 1950s homes was "Formica®", a plastic laminate that was used to surface furniture and cabinetry. Rangers are known to "demorph" involuntarily due to powerful physical attacks. Thin-film "plastic wrap" that could be purchased in rolls also helped keep food fresh. Helmets aside, the suits are donned and removed nearly instantaneously with a glow of light or some other effect. The Tupperware line of products was well thought out and highly effective, greatly reducing spoilage of foods in storage. Rangers appear to retain their original physiology beneath their suits when in morphed form, as Rangers' helmets have been seen removed or broken on numerous occasions, revealing his or her natural form underneath. One of the most visible parts of this plastics invasion was Earl Tupper's "Tupperware", a complete line of sealable polyethylene food containers that Tupper cleverly promoted through a network of housewives who sold Tupperware as a means of bringing in some money. A morphed Ranger generally possesses superhuman strength, durability, and hand-to-hand combat ability; unmorphed Rangers may possess other innate abilities (such as telepathy, superspeed, invisibility, etc.) which are usually not directly related to his or her Ranger powers. American consumers enthusiastically adopted the endless range of colorful, cheap, and durable plastic gimmicks being produced for new suburban home life. A Power Ranger is a person who "morphs" from a natural, unpowered form into a warrior clad in full-body, form-fitting spandex, as well as a plastic helmet with an opaque visor, which in many cases serves to protect his or her identity. New manufacturing were developed, using various forming, molding, casting, and extrusion processes, to churn out plastic products in vast quantities. Some seasons feature extremely large combinations of Zords known as "Ultrazords.". After the war, the new plastics that had been developed entered the consumer mainstream in a flood. Often before a monster is defeated, it will grow into gigantic proportions, forcing the Power Rangers to use gigantic (bio)mechanical machines known as "Zords." In many cases, these can be combined to form a more advanced humanoid machines, known as a "Megazord." Because of the way Zords are combined, the Power Rangers may also use interchangeable parts to enhance their fighting power, or combine Megazords together to form larger Megazords. GoreTex is also used for surgical implants; Teflon strand is used to make dental floss; and Teflon mixed with fluorine compounds is used to make "decoy" flares dropped by aircraft to distract heat-seeking missiles. To activate these powers, the Power Rangers, "morph" by performing a standard action and reciting a "morphing call." Throughout the series, the Power Rangers learn the importance of teamwork and perseverance as they battle progressively more difficult monsters. During the war, it was used in gaseous-diffusion processes to refine uranium for the atomic bomb, as the process was highly corrosive. Power Rangers was officially purchased by Disney in 2001. A Du Pont chemist named Roy Plunkett discovered Teflon by accident in 1938. Power Rangers was distributed by Saban Entertainment from 1993 until the end of 2001 and was broadcast on the Fox network. The polyfluoroethylene surface layer created by exposing a polyethylene container to fluorine gas is very similar to Teflon. Due to the very Japanese nature of many of Sentai's stories and design, the American shows are always at least slightly changed to fit a Western audience. One of the most impressive plastics used in the war, and a top secret, was "polytetrafluoroethylene" (PTFE), better known as "Teflon", which could be deposited on metal surfaces as a scratchproof and corrosion-resistant, low-friction protective coating. While the concept is based on the Super Sentai series of yearly serials, it is not an English dub of the original, but rather a 'new' production with English-speaking actors spliced in with the original Japanese footage to varying ratios. PET films, trade named "Mylar®", are used to make recording tape. The show is directly tied into a vast merchandising empire largely owned by Japanese toy company Bandai. PET is also strong and abrasion resistant, and is used for making mechanical parts, food trays, and other items that have to endure abuse. Power Rangers is an ongoing saga of television series about the epic adventures teenagers or 20-somethings who transform into the titular superheroes. PET is more impermeable than other low-cost plastics and so is a popular material for making bottles for Coca-Cola and other "fizzy drinks", since carbonation tends to attack other plastics, and for acidic drinks such as fruit or vegetable juices. There have been rare exceptions to this rule. Two chemists named Rex Whinfield and James Dickson, working at a small English company with the quaint name of the "Calico Printer's Association" in Manchester, developed "polyethylene terephthalate" (PET or PETE) in 1941, and it would be used for synthetic fibers in the postwar era, with names such as "polyester", "dacron", and "terylene". Vice versa, Rangers cannot shoot at a growing monster. Fiberglass is now often used to build sport boats, and carbon-epoxy composites are an increasingly important structural element in aircraft, as they are lightweight, strong, and heat resistant. Power Rangers follows a few unofficial anime conventions, namely that a villain cannot shoot while Rangers are morphing or while a Megazord is forming. Composites using epoxy as a matrix include glass-reinforced plastic, where the structural element is glass fiber, and "carbon-epoxy composites", in which the structural element is carbon fiber. His colors were Green, White (Mighty Morphin' Power Rangers, Red Power Rangers Zeo and Power Rangers: Turbo, and his latest and presumably final color, Black Power Rangers: Dino Thunder.). After the war they would come into wide use for coatings, "adhesives", and composite materials. Frank, who appeared in more episodes of the series than any other actor, is the only one to have appeared in five incarnations in the same role, and he has shared screen time with Rangers of each of the first thirteen different seasons. Epoxies are a class of thermoset plastic that form cross-links and "cure" when a catalyzing agent, or "hardener", is added. Tommy Oliver (Jason David Frank) is the only character to have worn four different colors as a Ranger. In 1939, IG Farben filed a patent for "polyepoxide" or "epoxy". Kendrix appeared periodically to assist her replacement Karone, and was returned to life in the season finale of Lost Galaxy. It is also one of the components (in non-blown form) of the fiber spandex. Valerie Vernon, who played the character, collapsed on set and was diagnosed with leukemia, forcing her to leave the show. It is used in everything from plastic bottles to carpets to plastic furniture, and is very heavily used in automobiles. Ninja Storm would be the first full Power Rangers season to feature a male Yellow Ranger and a female Blue Ranger, though the Alien Rangers miniseries had earlier featured a White female Ranger and a male Yellow Ranger. Polypropylene is similar to its ancestor, polyethylene, and shares polyethylene's low cost, but it is much more robust. Stock footage of the Japanese series became confusing to even casual viewers, but was considered acceptable because the Yellow Ranger would be so inconspicuous among five or more Rangers. Paul Hogan and Robert Banks, are now generally credited as the "official" inventors of the material. The Japanese Sentai series regularly switch between male and female Yellow Rangers, but as yellow is considered feminine in Western cultures, women were traditionally cast in the part for the Power Rangers adaptations regardless. Polypropylene managed to survive the legal process, and two American chemists working for Phillips Petroleum, J. Red, Blue, and Yellow are the only colors that have been a part of every Power Rangers team. It was a patent attorney's dream scenario, and litigation was not resolved until 1989. 2002 episode "Forever Red" gathered many different cast members from the show to commemorate the tenth anniversary of the franchise. It is common in modern science and technology that the growth of the general body of knowledge can lead to the same inventions in different places at about the same time, but polypropylene was an extreme case of this phenomenon, being separately invented about nine times. Power Rangers SPD Volumes 1 - 5, 2005, BVHE. Polyethylene would lead after the war to an improved material, "polypropylene" (PP), which was discovered in the early 1950s by Giulio Natta. Power Rangers Dino Thunder Volumes 1 - 5, 2004; BVHE. While PE has low resistance to chemical attack, it was found later that a PE container could be made much more robust by exposing it to fluorine gas, which modified the surface layer of the container into the much tougher "polyfluoroethylene". Power Rangers Ninja Storm Volumes 1 - 5, 2003; BVHE. LDPE is used to make films and packaging materials, while HDPE is used for containers, plumbing, and automotive fittings. The Best of the Power Rangers: The Ultimate Rangers, 2003; BVHE. Another important plastic, "polyethylene" (PE), sometimes known as "polythene", was discovered in 1933 by Reginald Gibson and Eric Fawcett at the British industrial giant Imperial Chemical Industries (ICI). Rangers fight and defeat said giant minion, usually using a flashy trademark move. Plexiglas was used to build aircraft canopies during the war, and it is also now used as a marble replacement for countertops. Optional: Rangers find that their current powers are insufficient to defeat monster and discover a new power, such as a Battlizer armor for the Red Ranger, a sixth Ranger, or a new Megazord. Although acrylics are now well known for their use in paints and synthetic fibers, such as "fake furs", in their bulk form they are actually very hard and more transparent than glass, and are sold as glass replacements under trade names such as "Plexiglas" and "Lucite". Evil enemy revives minion and makes minion grow to gigantic proportions, followed by Rangers summoning giant machines known as Zords and/or their combined form, the Megazord. By 1936, American, British, and German companies were producing polymethyl methacrylate (PMMA), better known as "acrylic". Rangers defeat minions/footsoldiers. Other plastics emerged in the prewar period, though some would not come into widespread use until after the war. Rangers morph. Ultimately, all large military rockets and missiles would use synthetic rubber based solid fuels, and they would also play a significant part in the civilian space effort. Rangers fight minions/footsoldiers. Such solid fuels could be cast into large, uniform blocks that had no cracks or other defects that would cause nonuniform burning. Rangers are attacked by evil enemy's minions/footsoldiers. By the mid-1950s, large missiles were being built using solid fuels based on synthetic rubber, mixed with ammonium perchlorate and high proportions of aluminium powder. Rangers are seen in everyday life with a dispute to resolve. After the war, the Caltech researchers began to investigate the use of synthetic rubbers instead of asphalt as the fuel in the mixture. This new solid fuel burned more slowly and evenly than nitrocellulose explosives, and was much less dangerous to store and use, though it tended to flow slowly out of the rocket in storage and the rockets using it had to be stockpiled nose down. During the war, California Institute of Technology (Caltech) researchers came up with a new solid fuel, based on asphalt fuel mixed with an oxidizer, such as potassium or ammonium percholorate, plus aluminium powder, which burns very hot. Solid rockets used during World War II used nitrocellulose explosives for propellants, but it was impractical and dangerous to make such rockets very big. Synthetic rubber would also play an important part in the space race and nuclear arms race. GR-S remains the primary synthetic rubber for the manufacture of tires. After the war, natural rubber plantations no longer had a stranglehold on rubber supplies, particularly after chemists learned to synthesize isoprene. By 1944 a total of 50 factories were manufacturing it, pouring out a volume of the material twice that of the world's natural rubber production before the beginning of the war. A principal scientist involved with the effort was Edward Robbins. government launched a major (and largely secret) effort to develop and refine synthetic rubber. The U.S. Military trucks needed rubber for tires, and rubber was used in almost every other war machine. Worldwide natural rubber supplies were limited, and by mid-1942 most of the rubber-producing regions were under Japanese control. synthetic rubber production during World War II. One such Buna rubber, known as "GR-S" ("Government Rubber Styrene), is a copolymer of butadiene and styrene, became the basis for U.S. These were "copolymers", meaning that their polymers were made up from not one but two monomers, in alternating sequence. In 1935, German chemists synthesized the first of a series of synthetic rubbers known as "Buna rubbers". Neoprene is highly resistant to heat and chemicals such as oil and gasoline, and is used in fuel hoses and as an insulating material in machinery. Bolton. These studies led in 1931 to one of the first successful synthetic rubbers, known as "neoprene", which was developed at DuPont under the direction of E.K. Practical synthetic rubber grew out of studies published in 1930 written independently by American Wallace Carothers, Russian scientist Lebedev and the German scientist Hermann Staudinger. The first synthetic rubber polymer was obtained by Lebedev in 1910. Another plastic that was critical to the war effort was "synthetic rubber", which was produced in a variety of forms. In its bulk form it is very wear resistant, and so is used to build gears, bearings, bushings, and other mechanical parts. Nylon still remains an important plastic, and not just for use in fabrics. After the war ended, Du Pont went back to selling nylon to the public, engaging in another promotional campaign in 1946 that resulted in an even bigger craze, triggering off "nylon riots". The production capacity that had been built up to produce nylon stockings, or just "nylons", for American women was taken over to manufacture vast numbers of parachutes for fliers and paratroopers. Nylon mania came to an abrupt stop at the end of 1941 when the USA entered World War II. With such a major investment, it was no surprise that Du Pont spared little expense to promote nylon after its introduction, creating a public sensation, or "nylon mania". It took Du Pont twelve years and US$27 million to refine nylon and develop the industrial processes for bulk manufacture. However, Du Pont's real target was silk, particularly silk stockings. The first application was for bristles for toothbrushes. His work led to the discovery of synthetic nylon fiber, which was very strong but also very flexible. He took some of the first steps on the road to "molecular design" of materials. Carothers had been hired to perform pure research, and not only investigated new materials, but worked to understand their molecular structure and how it related to material properties. Bolton. In 1927, Du Pont had begun a secret development project designated "Fiber66", under the direction of a Harvard chemists Wallace Carothers and Chemistry Department director E.K. Nylon was the first purely synthetic fiber, introduced by Du Pont Corporation at the 1939 World's Fair in New York City. The real star of the plastics industry in the 1930s was "polyamide" (PA), far better known by its trade name, "nylon". PVC can also be softened with chemical processing, and in this form it is now used for shrink-wrap, food packaging, and raingear. PVC in its normal form is stiff, strong, heat and weather resistant, and is now used for making plumbing, gutters, house siding, enclosures for computers and other electronics gear. PVC has side chains incorporating chlorine atoms, which form strong bonds. It would also be the basis for one of the most popular "foamed" plastics, under the name "styrene foam" or "Styrofoam". Polystyrene is a rigid, brittle plastic that is now used to make plastic model kits, disposable eating utensils, and similar knickknacks. Among the earliest examples in the wave of new plastics were "polystyrene" (PS) and "polyvinyl chloride" (PVC), developed by IG Farben of Germany. After the First World War, improvements in chemical technology led to an explosion in new forms of plastics. For example, some electronic circuit boards are made of sheets of paper or cloth impregnated with phenolic resin. Phenolic plastics have been largely replaced by cheaper and less brittle plastics, but they are still used in applications requiring its insulating and heat-resistant properties. government even considered making one-cent coins out of it when World War II caused a copper shortage. The U.S. It was molded into thousands of forms, such as radios, telephones, clocks, and, of course, billiard balls. Bakelite was cheap, strong, and durable. Thermoset plastics are tough and temperature resistant. Conventional "thermoplastics" can be molded and then melted again, but thermoset plastics form bonds between polymers strands when "cured", creating a tangled matrix that cannot be undone without destroying the plastic. It was also the first "thermoset" plastic. It was a purely synthetic material, not based on any material or even molecule found in nature. Bakelite was the first true plastic. When the Bakelite patent expired in 1927, the Catalin Corporation acquired the patent and began manufacturing Catalin plastic using a different process that allowed a wider range of coloring. It was originally used for electrical and mechanical parts, finally coming into widespread use in consumer goods in the 1920s. He publicly announced his discovery in 1909, naming it "bakelite". Baekeland built pressure vessels to force out the bubbles and provide a smooth, uniform product. The only problem was that the material tended to foam during synthesis, and the resulting product was of unacceptable quality. Most of these compositions were strong and fire resistant. He continued his investigations and found that the material could be mixed with wood flour, asbestos, or slate dust to create "composite" materials with different properties. Baekeland found that mixtures of phenol (C6H5OH) and formaldehyde (HCOH) formed a sticky mass when mixed together and heated, and the mass became extremely hard if allowed to cool and dry. A chemist named Leo Hendrik Baekeland, a Belgian-born American living in New York state, was searching for an insulating shellac to coat wires in electric motors and generators. The limitations of celluloid led to the next major advance, known as "phenolic" or "phenol-formaldehyde" plastics. It could also be produced in a transparent sheet form known as "cellophane". It is cheap and feels smooth on the skin, though it is weak when wet and creases easily. It still remains in production today, often in blends with other natural and artificial fibers. Art silk became well known under the trade name "rayon", and was produced in great quantities through the 1930s, when it was supplanted by better artificial fabrics. The three men sold the rights for the new fabric to the French Courtauld company, a major manufacturer of silk, which put it into production in 1905, using cellulose from wood pulp as the "feedstock" material. In 1894, three British inventors, Charles Cross, Edward Bevan, and Clayton Beadle, patented a new "artificial silk" or "art silk" that was much safer. After some ghastly accidents, Chardonnay silk was taken off the market. It was an attractive cloth, but like celluloid it was very flammable, a property completely unacceptable in clothing. In 1884, a French chemist, the Comte de Chardonnay, introduced a cellulose-based fabric that became known as "Chardonnay silk". While the men who developed celluloid were interested in replacing ivory, those who developed the new fibers were interested in replacing another expensive material, silk. Cellulose was also used to produce cloth. If the balls had been imperfectly manufactured, the paints might have acted as primer to set the rest of the ball off with a bang. These stories might have had a basis in fact, since the billiard balls were often celluloid covered with paints based on another, even more flammable, nitrocellulose product known as "collodion". Ping-pong balls, one of the few products still made with celluloid, sizzle and burn if set on fire, and Hyatt liked to tell stories about celluloid billiard balls exploding when struck very hard. However, celluloid still tended to yellow and crack over time, and it had another more dangerous defect: it burned very easily and spectacularly, unsurprising given that mixtures of nitric acid and cellulose are also used to synthesize smokeless powder. By the year 1900, movie film was a major market for celluloid. Hyatt figured out how to fabricate the material in a strip format for movie film. Celluloid could also be used in entirely new applications. Such pretty trinkets were no longer only for the rich. For example, celluloid combs made to tie up the long tresses of hair fashionable at the time are now jewellike museum pieces. Some of the items made with cellulose in the nineteenth century were beautifully designed and implemented. Celluloid proved extremely versatile in its field of application, providing a cheap and attractive replacement for ivory, tortoiseshell, and bone, and traditional products that had used these materials were much easier to fabricate with plastics. Corsets made with celluloid stays also proved popular, since perspiration did not rust the stays, as it would if they had been made of metal. They did not wilt and did not stain easily, and Hyatt sold them by trainloads. Celluloid's real breakthrough products were waterproof shirt collars, cuffs, and the false shirtfronts known as "dickies", whose unmanageable nature later became a stock joke in silent-movie comedies. However, celluloid dentures tended to soften when hot, making tea drinking tricky, and the camphor taste tended to be difficult to suppress. One of the first products were dental pieces, and sets of false teeth built around celluloid proved cheaper than existing rubber dentures. It was introduced in 1863. Since cellulose was the main constituent used in the synthesis of his new material, Hyatt named it "celluloid". Hyatt was something of an industrial genius who understood what could be done with such a shapeable, or "plastic", material, and proceeded to design much of the basic industrial machinery needed to produce good-quality plastic materials in quantity. Parkes had failed for lack of a proper softener, but Hyatt discovered that camphor would do the job very nicely. An American printer and amateur inventor named John Wesley Hyatt took up where Parkes left off. However, Parkes was not able to scale up the process to an industrial level, and products made from Parkesine quickly warped and cracked after a short period of use. The output of the process hardened into a hard, ivory-like material that could be molded when heated. Parkesine was made from cellulose treated with nitric acid and a solvent. An Englishman from Birmingham named Alexander Parkes developed a "synthetic ivory" named "pyroxlin", which he marketed under the trade name "Parkesine", and which won a bronze medal at the 1862 World's fair in London. Ivory was a particularly attractive target for a synthetic replacement. Inventors were particularly interested in developing synthetic substitutes for those natural materials that were expensive and in short supply, since that meant a profitable market to exploit. The next logical step was to use a natural polymer, cellulose, as the basis for a new material. All Goodyear had done with vulcanization was improve the properties of a natural polymer. Vulcanization creates sulfur bonds that link separate isoprene polymers together, improving the material's structural integrity and its other properties. Natural rubber is composed of an organic polymer named "isoprene". Vulcanization remains an important industrial process for the manufacture of rubber in both natural and artificial forms. Compared to untreated natural rubber, Goodyear's "vulcanized rubber" was stronger, more resistant to abrasion, more elastic, much less sensitive to temperature, impermeable to gases, and highly resistant to chemicals and electric current. The rubber seemed to have improved properties; Goodyear followed up with further experiments, and developed a process known as "vulcanization" that involved cooking the rubber with sulfur. In 1839, the American inventor Charles Goodyear was experimenting with the sulfur treatment of natural rubber when, according to legend, he dropped a piece of sulfur-treated rubber on a stove. In 1834, two inventors, Friedrich Ludersdorf of Germany and Nathaniel Hayward of the U.S., independently discovered that adding sulfur to raw rubber helped prevent the material from becoming sticky. Natural rubber was sensitive to temperature, becoming sticky and smelly in hot weather and brittle in cold weather. Eventually, inventors learned to improve the properties of natural polymers. A plant polymer named "cellulose" provides the structural strength for natural fibers and ropes, and by the early 19th century natural rubber, tapped from rubber trees, was widespread use. People have been using natural organic polymers for centuries in the form of waxes and shellacs. . The development of plastics has come from the use of natural materials (e.g., chewing gum, shellac) to the use of chemically modified natural materials (e.g., natural rubber, nitrocellulose) and finally to completely manmade molecules (e.g., epoxy, polyvinyl chloride, polyethylene). The first plastic based on a synthetic polymer was called Bakelite and was created by Leo Hendrik Baekeland in 1907. In the nineteenth century the discovered plastics based on chemically modified natural polymers: Charles Goodyear discovered vulcanization of rubber (1839) and Alexander Parkes discovered cellulose-based plastics in 1860s. People experimented with plastics based on natural polymers for centuries. This customization by pendant groups has allowed plastics to become such an indispensable part of twenty first-century life by fine tuning the properties of the polymer. To customize the properties of a plastic, different molecular groups "hang" from the backbone (usually they are "hung" as part of the monomers before linking monomers together to form the polymer chain). (Some of commercial interest are silicon based.) The backbone is that part of the chain on the main "path" linking the multitude of monomer units together. The vast majority of plastics are composed of polymers of carbon alone or with oxygen, nitrogen, chlorine or sulfur in the backbone. These chains are made up of many repeating molecular units, or "monomers". Plastics are polymers: long chains of atoms bonded to one another. Many plastics are partially crystalline and partially amorphous in molecular structure, giving them both a melting point (the temperature at which the covalent bonds dissolve) and one or more glass transitions (temperatures at which the degree of cross-linking is substantially reduced). thermoset, elastomer, engineering plastic, addition or condensation, and Glass transition temperature or Tg. Other classifications include thermoplastic vs. Plastic can be classified in many ways but most commonly by their polymer backbone (polyvinyl chloride, polyethylene, acrylic, silicone, urethane, etc.). Plastic may also refer to any material characterized by deformation or failure under shear stress; see plasticity and ductility. Combined with this adaptability, the general uniformity of composition and light weight of plastics ensures their use in almost all industrial segments. Plastics are designed with immense variation in properties such as heat tolerance, hardness, resiliency and many others. Their name is derived from the fact that many are malleable, having the property of plasticity. Plastics can be formed into objects or films or fibers. There are few natural polymers generally considered to be "plastics". They are composed of organic condensation or addition polymers and may contain other substances to improve performance or economics. Plastic is a term that covers a range of synthetic or semisynthetic polymerization products. OTHER: Other - This plastic category, as its name of "other" implies, is any plastic other than the named #1–#6, Commonly found on: certain kinds of food containers and Tupperware. PS: Polystyrene - Commonly found on: packaging pellets or "Styrofoam peanuts," cups, plastic tableware, meat trays, take-away food clamshell containers. PP: Polypropylene - Commonly found on: bottle caps, drinking straws. LDPE: Low Density Polyethylene - Commonly found on: dry-cleaning bags, produce bags, trash can liners, food storage containers. PVC: Polyvinyl Chloride - Commonly found on: plastic pipes, outdoor furniture, shrink-wrap, water bottles, salad dressing and liquid detergent containers. HDPE: High Density Polyethylene - Commonly found on: detergent bottles, milk jugs. PETE: Polyethylene Terephthalate - Commonly found on: 2-litre soft drink bottles, cooking oil bottles, peanut butter jars. |