Pearl

According to Rebbenu Bachya, the word "Yahalom" in the verse Exodus 28:18 means "Pearl" and was the stone on the Ephod representing the tribe of Zebulun. Already, bowling balls, golf balls, sports equipment, and waterproof cotton balls have been made of nanocarbons. Necklaces can also be classified as uniform, where all the pearls are the same size, graduated, where the pearls are arranged in size from large in the centre to smaller at the ends, or tin cup, where pearls are generally the same size, but separated by lengths of chain. In addition, nanocarbon manufacturing is low to nonpolluting. An opera will be long enough to reach the breastbone or sternum of the wearer, and longer still, a pearl rope is any length that falls down further than an opera. 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. A matinee of pearls falls just above the breasts. All three of these are made of nanocarbons, products of the new nanotechnology.

The size called a princess comes down to or just below the collarbone. The most promising alternatives to plastic are graphene, carbon nanotube, and carbon nanofoam. Pearl chokers nestle just at the base of the neck. Some are many times stronger than plastic, but crack if made thin like cellophane. A collar will sit directly against the throat and not hang down the neck at all, they are often made up of multiple strands of pearls. Some of these alternatives are too expensive or not malleable enough, but can be used in some plastic applications. While most other necklaces are simply referred to by their physical measurement, strings of pearls have their own set of names that characterize the pearls based on where they hang when worn around the neck. 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.

There is also a unique way of naming pearl necklaces. Scientists are seeking cheaper alternatives to plastic. Although imitation pearls look the part, they do not have the same weight or smoothness as real pearls, and their luster will also dim greatly. Thus, even if alternative sources are used, costs will continue to rise. Some imitation pearls are simply made of mother-of-pearl, coral or conch, while others are made from glass and are coated with a solution containing fish scales called essence d'Orient. 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. Imitation pearls are much easier to identify by jewellers. 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.

If the centre is not perfectly round, the jeweller recognises that it is genuine, and gives it a higher value. In 2004, the higher price of plastic drove a number of plastic-toy manufacturers out of business. This is because when the cultivators insert the grit, (usually a polished piece of mussel shell), it is always pefectly round, so as to produce a more expensive, perfectly round pearl. As the cost of plastic hinges on the cost of petroleum, should petroleum prices continue to rise, so will the cost of plastic. If the grit in the centre of the pearl is a perfect sphere, then the jeweller knows it is cultivated. The cause of the increase is the sharply rising cost of petroleum, the raw material that is chemically altered to form commercial plastics. One way that jewellers can determine whether a pearl is cultivated or natural is by x-raying the pearl. However, in recent years the cost of plastics has been rising dramatically.

In general, cultivated pearls are less valuable than natural pearls, and imitation pearls are the least expensive. One of the great appeals of plastics have been their low price as compared to other materials. Ringed pearls are characterized by concentric ridges, or rings, around the body of the pearl. 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. They are also commonly seen in necklaces. The Courtauld concern, the original producer of rayon, came up with a revised process for the material in the mid-1980s to produce "Tencel". Baroque pearls have a different appeal to them than more standard shapes because they are often highly irregular and make unique and interesting shapes. There have been some success stories.

Drop and pear shaped pearls are sometimes referred to as teardrop pearls and are most often seen in earrings, pendants, or as a center pearl in a necklace. In this regard, though, plastics are no worse than food or paper, which also fail to degrade in landfills. Button pearls are like a slightly flattened round pearl and can also make a necklace, but are more often used in single pendants or earrings where the back half of the pearl is covered, making it look like a larger, round pearl. When such plastic materials are dumped into landfills, they can become "mummified" and persist for decades even if they are supposed to be biodegradable. Semi-rounds are also used in necklaces or in pieces where the shape of the pearl can be disguised to look like it is a perfectly round pearl. 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. Perfectly round pearls are the rarest and most expensive, and are generally used in necklaces, or strings of pearls. 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.

Pearls come in eight basic shapes: round, semi-round, button, drop, pear, oval, baroque, and ringed. BASF make Ecoflex, a fully biodegradable polyester for food packaging applications. Irregular shaped pearls are often used in necklaces. Some researchers have actually genetically engineered bacteria that synthesize a completely biodegradable plastic, but this material is expensive at present. Teardrop-shaped pearls are often used in pendants. 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. Large, perfectly round pearls are rare and highly valued. Research has been done on biodegradable plastics that break down with exposure to sunlight.

All factors being equal, however, the larger the pearl the more valuable it is. 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. Among those attributes, luster is the most important differentiator of pearl quality according to jewelers. is very small, somewhere around 5%. The value of the pearls in jewelry is determined by a combination of the luster, color, size, lack of surface flaw and symmetry that are appropriate for the type of pearl under consideration. Currently, the percentage of plastics recycled in the U.S. Cultured pearls are also produced using abalone. These unrecyclable wastes can be disposed of in landfills, incinerated or used to produce electricity at waste-to-energy plants.

Freshwater pearls are characterized by the reflection of rainbow colors in the luster. For example, polystyrene is rarely recycled because it is usually not cost effective. In the 1990s, Japanese pearl producers also invested in producing cultured pearls with freshwater mussels in the region of Shanghai, China, and in Fiji. Recycling certain types of plastics can be unprofitable, as well. Japanese pearl farmers now culture a hybrid pearl mussel—a cross between the last remaining Biwa Pearl Mussels and a closely related species from China—in other Japanese lakes. 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. Since the time of peak production in 1971, when Biwa pearl farmers produced six tons of cultured pearls, pollution and overharvesting have caused the virtual extinction of this animal. 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.

The extensive and successful use of the Biwa Pearl Mussel is reflected in the name "Biwa pearls," a phrase nearly synonymous with freshwater pearls in general. Other recyclable materials, such as metals, are easier to process mechanically. This lake, the largest and most ancient in Japan, lies near the city of Kyoto. Typically, workers sort the plastic by looking at the resin identification code, though common containers like soda bottles can be sorted from memory. In 1914 pearl farmers began culturing freshwater pearls using the pearl mussels native to Lake Biwa. The biggest problem with plastics recycling is that it is difficult to automate the sorting of plastic waste, and so it is labor intensive. Tahitian pearls (also referred to as Titian pearls) are also another South Sea pearl. Unfortunately, recycling plastics has proven difficult.

Australia is one of the most important sources of South Sea pearls. A recyclable plastic container using this scheme is marked with a triangle of three "chasing arrows", which enclose a number giving the plastic type:. Sizes up to 14 mm in diameter are not uncommon. 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. South Sea pearls are characterized by their large size and silvery color. There are methods by which plastics can be broken back down to a feedstock state. One of the largest pearl-bearing oysters is the Pinctada maxima, which is roughly the size of a dinner plate. 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 the past couple of decades, cultured pearls have been produced with larger oysters in the south Pacific and Indian Ocean. By the 1990s, plastic recycling programs were common in the United States and elsewhere. The original Japanese cultured pearls, known as Akoya pearls, are produced by a species of small oysters no bigger than 6 to 7 cm in size, hence Japanese pearls larger than 10 mm in diameter are extremely rare and highly priced. For example, plastics make cars lighter, thus saving oil and reducing CO₂ emissions. Oysters which survive the subsequent surgery to remove the finished pearl are often implanted with a new, larger nucleus as part of the same procedure and then returned to the water for another three years of growth. Furthermore, it can be claimed that the use of plastics helps the environment by saving water and oil. Along with a small scrap of mantle tissue from another oyster to serve as an irritant, it is surgically implanted near the oyster's genitals. However, it should be noted that plastics only consume 4% of the world's oil production.

The nucleus is generally a polished bead made from mussel shell. Also, the manufacturing of plastics often creates large quantities of chemical pollutants, and requires use of the Earth's limited supply of fossil fuels. This mariculture process was first developed by Kokichi Mikimoto in Japan, who was granted a patent for the process in 1896. In some cases, burning plastic can release toxic fumes. The pearls are usually harvested three years after the planting, but it can take up to as long as six years before a pearl is produced. Plastics are almost too good, as they are durable and degrade very slowly. Now, however, almost all pearls used for jewelry are cultured by planting a core or nucleus into pearl oysters. Although plastics have had a remarkable impact globally, it has become increasingly obvious that there is a price to be paid for their use.

In fact, in a haul of three tonnes, only three or four oysters will produce perfect pearls. 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. Not all natural oysters produce pearls, however. Du Pont developed "Kevlar", an extremely strong synthetic fiber that was best known for its use in bullet-proof vests and combat helmets. Divers manually pulled oysters from ocean floors and river bottoms and checked them individually for pearls. General Electric introduced "lexan", a high-impact "polycarbonate" plastic, in the 1970s. Before the beginning of the 20th Century, pearl hunting was the most common way of harvesting pearls. Plastics continue to be improved.

. Polyurethane foam was used to fill mattresses, and Styrofoam was used to line ice coolers and make float toys. Black pearls, frequently refered to as Black Tahitian Pearls are highly valued because of their rarity; the culturing process for them dictates a smaller volume output due to rejection by the oysters. Composite materials like fiberglass came into use for building boats and, in some cases, cars. Pearls are usually white, sometimes with a creamy or pinkish tinge, but may be tinted with yellow, green, blue, brown, purple, or black. 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. The iridescence that some pearls display is caused by the overlapping of successive layers, which breaks up light falling on the surface. 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.

The unique luster of pearls depends upon the reflection and refraction of light from the translucent layers and is finer in proportion as the layers become thinner and more numerous. Formica was durable and attractive. This combination of calcium carbonate and conchiolin is called nacre, or as most know it, mother-of-pearl. Another prominent element in 1950s homes was "Formica®", a plastic laminate that was used to surface furniture and cabinetry. As a response to an irritating object inside its shell, the mollusk will deposit layers of calcium carbonate (CaCO₃) in the form of the minerals aragonite or calcite (both crystalline forms of calcium carbonate) held together by an organic horn-like compound called conchiolin. Thin-film "plastic wrap" that could be purchased in rolls also helped keep food fresh. Pearls are formed inside the shell of certain bivalve mollusks. The Tupperware line of products was well thought out and highly effective, greatly reducing spoilage of foods in storage.

Pearl is valued as a gemstone and is cultivated or harvested for jewellery. 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 pearl is a hard, rounded object produced by certain mollusks, primarily oysters. American consumers enthusiastically adopted the endless range of colorful, cheap, and durable plastic gimmicks being produced for new suburban home life. New manufacturing were developed, using various forming, molding, casting, and extrusion processes, to churn out plastic products in vast quantities. After the war, the new plastics that had been developed entered the consumer mainstream in a flood.

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.
Teflon was later used to synthesize the breathable fabric "Gore-Tex", which can be used to build raingear that in principle "breathes" to keep the wearer's moisture from building up.
. By the early 1960s, Teflon "nonstick" frying pans were a hot consumer item.

During the war, it was used in gaseous-diffusion processes to refine uranium for the atomic bomb, as the process was highly corrosive. A Du Pont chemist named Roy Plunkett discovered Teflon by accident in 1938. The polyfluoroethylene surface layer created by exposing a polyethylene container to fluorine gas is very similar to Teflon. 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.

PET films, trade named "Mylar®", are used to make recording tape. 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 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. 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".

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. 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. After the war they would come into wide use for coatings, "adhesives", and composite materials. Epoxies are a class of thermoset plastic that form cross-links and "cure" when a catalyzing agent, or "hardener", is added.

In 1939, IG Farben filed a patent for "polyepoxide" or "epoxy". It is also one of the components (in non-blown form) of the fiber spandex.
Polyurethane was invented by Friedrich Bayer & Company in 1937, and would come into use after the war, in blown form for mattresses, furniture padding, and thermal insulation.
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It is used in everything from plastic bottles to carpets to plastic furniture, and is very heavily used in automobiles. Polypropylene is similar to its ancestor, polyethylene, and shares polyethylene's low cost, but it is much more robust. Paul Hogan and Robert Banks, are now generally credited as the "official" inventors of the material. Polypropylene managed to survive the legal process, and two American chemists working for Phillips Petroleum, J.

It was a patent attorney's dream scenario, and litigation was not resolved until 1989. 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. Polyethylene would lead after the war to an improved material, "polypropylene" (PP), which was discovered in the early 1950s by Giulio Natta. 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".

LDPE is used to make films and packaging materials, while HDPE is used for containers, plumbing, and automotive fittings.
PEs are cheap, flexible, durable, and chemically resistant.
. This material evolved into two forms, "low density polyethylene" (LDPE), and "high density polyethylene" (HDPE).

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). Plexiglas was used to build aircraft canopies during the war, and it is also now used as a marble replacement for countertops. 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". By 1936, American, British, and German companies were producing polymethyl methacrylate (PMMA), better known as "acrylic".

Other plastics emerged in the prewar period, though some would not come into widespread use until after the war. 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. Such solid fuels could be cast into large, uniform blocks that had no cracks or other defects that would cause nonuniform burning. 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.

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.
. 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.

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 T_g. 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.