This is made to lend a much better understanding concerning how plastics are produced, the several types of plastic and their numerous properties and applications.
A plastic is a type of synthetic or man-made polymer; similar often to natural resins found in trees along with other plants. Webster’s Dictionary defines polymers as: any kind of various complex organic compounds made by polymerization, competent at being molded, extruded, cast into various shapes and films, or drawn into filaments and after that used as textile fibers.
Just A Little HistoryThe background of manufactured plastics dates back over a hundred years; however, when compared with many other materials, plastics are relatively modern. Their usage during the last century has allowed society to create huge technological advances. Although plastics are looked at as a modern day invention, there have always been “natural polymers” for example amber, tortoise shells and animal horns. These materials behaved similar to today’s manufactured plastics and were often used just like the way manufactured plastics are presently applied. For example, before the sixteenth century, animal horns, which become transparent and pale yellow when heated, were sometimes accustomed to replace glass.
Alexander Parkes unveiled the initial man-made plastic with the 1862 Great International Exhibition in London. This product-which had been dubbed Parkesine, now called celluloid-was an organic material derived from cellulose that when heated may be molded but retained its shape when cooled. Parkes claimed that the new material could a single thing that rubber was effective at, yet at a lower price. He had discovered a material that could be transparent along with carved into 1000s of different shapes.
In 1907, chemist Leo Hendrik Baekland, while striving to make a synthetic varnish, came across the formula for a new synthetic polymer caused by coal tar. He subsequently named the new substance “Bakelite.” Bakelite, once formed, could not really melted. Due to the properties as being an electrical insulator, Bakelite was adopted in the creation of high-tech objects including cameras and telephones. It had been also utilized in producing ashtrays and as a substitute for jade, marble and amber. By 1909, Baekland had coined “plastics” because the term to clarify this completely new category of materials.
The first patent for pvc pellet, a substance now used widely in vinyl siding and water pipes, was registered in 1914. Cellophane had also been discovered during this time.
Plastics failed to really pull off until once the First World War, by using petroleum, a substance much easier to process than coal into raw materials. Plastics served as substitutes for wood, glass and metal in the hardship times during the World War’s I & II. After World War 2, newer plastics, for example polyurethane, polyester, silicones, polypropylene, and polycarbonate joined polymethyl methacrylate and polystyrene and PVC in widespread applications. More would follow and by the 1960s, plastics were within everyone’s reach because of the inexpensive cost. Plastics had thus come to be considered ‘common’-a symbol of your consumer society.
Because the 1970s, we certainly have witnessed the advent of ‘high-tech’ plastics used in demanding fields including health insurance and technology. New types and types of plastics with new or improved performance characteristics continue being developed.
From daily tasks to your most unusual needs, plastics have increasingly provided the performance characteristics that fulfill consumer needs by any means levels. Plastics are utilized such a wide array of applications as they are uniquely competent at offering a number of properties that provide consumer benefits unsurpassed by many other materials. Also, they are unique for the reason that their properties might be customized for every individual end use application.
Oil and natural gas are the major raw materials utilized to manufacture plastics. The plastics production process often begins by treating components of crude oil or natural gas inside a “cracking process.” This method results in the conversion of the components into hydrocarbon monomers like ethylene and propylene. Further processing results in a wider array of monomers for example styrene, upvc compound, ethylene glycol, terephthalic acid and others. These monomers are then chemically bonded into chains called polymers. The various mixtures of monomers yield plastics with an array of properties and characteristics.
PlasticsMany common plastics are made from hydrocarbon monomers. These plastics are made by linking many monomers together into long chains to create a polymer backbone. Polyethylene, polypropylene and polystyrene are the most common samples of these. Below can be a diagram of polyethylene, the best plastic structure.
Whilst the basic makeup of several plastics is carbon and hydrogen, other elements may also be involved. Oxygen, chlorine, fluorine and nitrogen will also be found in the molecular makeup of countless plastics. Polyvinyl chloride (PVC) contains chlorine. Nylon contains nitrogen. Teflon contains fluorine. Polyester and polycarbonates contain oxygen.
Characteristics of Plastics Plastics are split up into two distinct groups: thermoplastics and thermosets. The majority of plastics are thermoplastic, meaning that as soon as the plastic is actually created it may be heated and reformed repeatedly. Celluloid is a thermoplastic. This property allows for easy processing and facilitates recycling. One other group, the thermosets, can not be remelted. Once these plastics are formed, reheating can cause the material to decompose as an alternative to melt. Bakelite, poly phenol formaldehyde, is actually a thermoset.
Each plastic has very distinct characteristics, but a majority of plastics have the following general attributes.
Plastics can be quite proof against chemicals. Consider all of the cleaning fluids in your house that are packaged in plastic. The warning labels describing what will happen when the chemical comes into connection with skin or eyes or maybe ingested, emphasizes the chemical resistance of the materials. While solvents easily dissolve some plastics, other plastics provide safe, non-breakable packages for aggressive solvents.
Plastics might be both thermal and electrical insulators. A stroll by your house will reinforce this idea. Consider each of the electrical appliances, cords, outlets and wiring that are made or engrossed in plastics. Thermal resistance is evident in the kitchen area with plastic pot and pan handles, coffee pot handles, the foam core of refrigerators and freezers, insulated cups, coolers and microwave cookware. The thermal underwear that a great many skiers wear consists of polypropylene and also the fiberfill in several winter jackets is acrylic or polyester.
Generally, plastics are really lightweight with varying levels of strength. Consider all the different applications, from toys towards the frame structure of space stations, or from delicate nylon fiber in pantyhose to Kevlar®, which is used in bulletproof vests. Some polymers float in water while some sink. But, when compared to the density of stone, concrete, steel, copper, or aluminum, all plastics are lightweight materials.
Plastics may be processed in a variety of ways to produce thin fibers or very intricate parts. Plastics might be molded into bottles or aspects of cars, including dashboards and fenders. Some pvcppellet stretch and are very flexible. Other plastics, for example polyethylene, polystyrene (Styrofoam™) and polyurethane, can be foamed. Plastics can be molded into drums or even be mixed with solvents to get adhesives or paints. Elastomers and several plastics stretch and so are very flexible.
Polymers are materials with a seemingly limitless array of characteristics and colours. Polymers have several inherent properties that may be further enhanced by a wide range of additives to broaden their uses and applications. Polymers can be made to mimic cotton, silk, and wool fibers; porcelain and marble; and aluminum and zinc. Polymers could also make possible products which do not readily range from natural world, like clear sheets, foamed insulation board, and versatile films. Plastics may be molded or formed to create many kinds of merchandise with application in several major markets.
Polymers are often made of petroleum, yet not always. Many polymers are made from repeat units produced by natural gas or coal or crude oil. But foundation repeat units can sometimes be made out of renewable materials such as polylactic acid from corn or cellulosics from cotton linters. Some plastics have been made out of renewable materials for example cellulose acetate useful for screwdriver handles and gift ribbon. If the foundations can be produced more economically from renewable materials than from non-renewable fuels, either old plastics find new raw materials or new plastics are introduced.
Many plastics are combined with additives because they are processed into finished products. The additives are incorporated into plastics to change and enhance their basic mechanical, physical, or chemical properties. Additives are utilized to protect plastics from your degrading outcomes of light, heat, or bacteria; to improve such plastic properties, for example melt flow; to supply color; to deliver foamed structure; to offer flame retardancy; as well as provide special characteristics for example improved surface appearance or reduced tack/friction.
Plasticizers are materials included in certain plastics to improve flexibility and workability. Plasticizers can be found in several plastic film wraps as well as in flexible plastic tubing, each of which are typically utilized in food packaging or processing. All plastics utilized in food contact, like the additives and plasticizers, are regulated by the U.S. Food and Drug Administration (FDA) to make sure that these materials are secure.
Processing MethodsThere are many different processing methods employed to make plastic products. Here are the four main methods through which plastics are processed to produce the merchandise that consumers use, such as plastic film, bottles, bags as well as other containers.
Extrusion-Plastic pellets or granules are first loaded into a hopper, then fed into an extruder, and that is a long heated chamber, through which it is actually moved by the act of a continuously revolving screw. The plastic is melted by a mixture of heat from your mechanical work done and also by the sidewall metal. After the extruder, the molten plastic is forced out through a small opening or die to shape the finished product. As being the plastic product extrudes in the die, it is cooled by air or water. Plastic films and bags are made by extrusion processing.
Injection molding-Injection molding, plastic pellets or granules are fed from the hopper in a heating chamber. An extrusion screw pushes the plastic through the heating chamber, where material is softened into a fluid state. Again, mechanical work and hot sidewalls melt the plastic. Following this chamber, the resin is forced at high-pressure into a cooled, closed mold. As soon as the plastic cools to your solid state, the mold opens along with the finished part is ejected. This procedure can be used to create products including butter tubs, yogurt containers, closures and fittings.
Blow molding-Blow molding is actually a process used along with extrusion or injection molding. In a single form, extrusion blow molding, the die forms a continuous semi-molten tube of thermoplastic material. A chilled mold is clamped round the tube and compressed air is going to be blown to the tube to conform the tube for the interior of the mold and to solidify the stretched tube. Overall, the target is to generate a uniform melt, form it in a tube together with the desired cross section and blow it to the exact shape of the item. This procedure is utilized to manufacture hollow plastic products as well as its principal advantage is its ability to produce hollow shapes while not having to join 2 or more separately injection molded parts. This process is utilized to make items like commercial drums and milk bottles. Another blow molding method is to injection mold an intermediate shape termed as a preform then to heat the preform and blow the temperature-softened plastic in to the final shape in a chilled mold. This is basically the process to help make carbonated soft drink bottles.
Rotational Molding-Rotational molding includes closed mold installed on a piece of equipment capable of rotation on two axes simultaneously. Plastic granules are put within the mold, which can be then heated inside an oven to melt the plastic Rotation around both axes distributes the molten plastic into a uniform coating on the inside of the mold till the part is placed by cooling. This procedure is commonly used to help make hollow products, by way of example large toys or kayaks.
Durables vs. Non-DurablesAll types of plastic products are classified inside the plastic industry to be either a durable or non-durable plastic good. These classifications are utilized to make reference to a product’s expected life.
Products using a useful life of three years or even more are called durables. They include appliances, furniture, electronic products, automobiles, and building and construction materials.
Products having a useful life of under three years are typically called non-durables. Common applications include packaging, trash bags, cups, eating utensils, sporting and recreational equipment, toys, medical devices and disposable diapers.
Polyethylene Terephthalate (PET or PETE) is obvious, tough and has good gas and moisture barrier properties so that it is well suited for carbonated beverage applications along with other food containers. The fact that it has high use temperature allows that it is found in applications like heatable pre-prepared food trays. Its heat resistance and microwave transparency ensure it is an ideal heatable film. Additionally, it finds applications in these diverse end uses as fibers for clothing and carpets, bottles, food containers, strapping, and engineering plastics for precision-molded parts.
High Density Polyethylene (HDPE) is used for most packaging applications mainly because it provides excellent moisture barrier properties and chemical resistance. However, HDPE, like all sorts of polyethylene, has limitations to the people food packaging applications which do not require an oxygen or CO2 barrier. In film form, HDPE is used in snack food packages and cereal box liners; in blow-molded bottle form, for milk and non-carbonated beverage bottles; and also in injection-molded tub form, for packaging margarine, whipped toppings and deli foods. Because HDPE has good chemical resistance, it is employed for packaging many household in addition to industrial chemicals like detergents, bleach and acids. General uses of HDPE include injection-molded beverage cases, bread trays and also films for grocery sacks and bottles for beverages and household chemicals.
Polyvinyl Chloride (PVC) has excellent transparency, chemical resistance, long-term stability, good weatherability and stable electrical properties. Vinyl products can be broadly split into rigid and flexible materials. Rigid applications are concentrated in construction markets, including pipe and fittings, siding, rigid flooring and windows. PVC’s success in pipe and fittings could be attributed to its resistance to most chemicals, imperviousness to attack by bacteria or micro-organisms, corrosion resistance and strength. Flexible vinyl can be used in wire and cable sheathing, insulation, film and sheet, flexible floor coverings, synthetic leather products, coatings, blood bags, and medical tubing.
Low Density Polyethylene (LDPE) is predominantly used in film applications because of its toughness, flexibility and transparency. LDPE features a low melting point which makes it popular for usage in applications where heat sealing is important. Typically, LDPE can be used to manufacture flexible films for example those utilized for dry cleaned garment bags and produce bags. LDPE can also be used to manufacture some flexible lids and bottles, in fact it is widely used in wire and cable applications for its stable electrical properties and processing characteristics.
Polypropylene (PP) has excellent chemical resistance and it is widely used in packaging. It possesses a high melting point, so that it is suitable for hot fill liquids. Polypropylene can be found in anything from flexible and rigid packaging to fibers for fabrics and carpets and big molded parts for automotive and consumer products. Like other plastics, polypropylene has excellent resistance to water as well as salt and acid solutions that are destructive to metals. Typical applications include ketchup bottles, yogurt containers, medicine bottles, pancake syrup bottles and automobile battery casings.
Polystyrene (PS) is really a versatile plastic that may be rigid or foamed. General purpose polystyrene is clear, hard and brittle. Its clarity allows it to be used when transparency is very important, like medical and food packaging, in laboratory ware, as well as in certain electronic uses. Expandable Polystyrene (EPS) is commonly extruded into sheet for thermoforming into trays for meats, fish and cheeses and into containers like egg crates. EPS is also directly formed into cups and tubs for dry foods for example dehydrated soups. Both foamed sheet and molded tubs are employed extensively in take-out restaurants with regard to their lightweight, stiffness and excellent thermal insulation.
If you are aware of it or otherwise, plastics play a significant part in your life. Plastics’ versatility permit them to be used in anything from car parts to doll parts, from soft drink bottles to the refrigerators they can be kept in. Through the car you drive to operate in to the television you watch in the home, plastics make your life easier and better. So how will it be that plastics have grown to be so commonly used? How did plastics become the material preferred by countless varied applications?
The basic response is that plastics offers the points consumers want and desire at economical costs. Plastics hold the unique capacity to be manufactured to fulfill very specific functional needs for consumers. So maybe there’s another question that’s relevant: Precisely what do I want? Regardless how you answer this, plastics can probably satisfy your needs.
If your product is made from plastic, there’s reasons. And odds are the key reason why has everything related to assisting you, the consumer, get what you wish: Health. Safety. Performance. and Value. Plastics Make It Possible.
Just consider the changes we’ve seen in the food market lately: plastic wrap assists in keeping meat fresh while protecting it from the poking and prodding fingers of your own fellow shoppers; plastic bottles mean it is possible to lift an economy-size bottle of juice and ought to you accidentally drop that bottle, it really is shatter-resistant. In each case, plastics make your life easier, healthier and safer.
Plastics also help you to get maximum value from some of the big-ticket items you buy. Plastics help make portable phones and computers that basically are portable. They guide major appliances-like refrigerators or dishwashers-resist corrosion, last longer and operate more efficiently. Plastic car fenders and body panels resist dings, so you can cruise the food store car park with confidence.
Modern packaging-including heat-sealed plastic pouches and wraps-helps keep food fresh and free from contamination. Which means the resources that went into producing that food aren’t wasted. It’s the same after you get the food home: plastic wraps and resealable containers keep the leftovers protected-much towards the chagrin of kids everywhere. The truth is, packaging experts have estimated that every pound of plastic packaging helps to reduce food waste by as much as 1.7 pounds.
Plastics can also help you bring home more product with less packaging. By way of example, just 2 pounds of plastic can deliver 1,300 ounces-roughly 10 gallons-of any beverage for example juice, soda or water. You’d need 3 pounds of aluminum to take home the equivalent amount of product, 8 pounds of steel or older 40 pounds of glass. In addition plastic bags require less total energy to generate than paper bags, they conserve fuel in shipping. It will require seven trucks to handle the identical quantity of paper bags as fits in one truckload of plastic bags. Plastics make packaging more efficient, which ultimately conserves resources.
LightweightingPlastics engineers are always working to do more with less material. Since 1977, the 2-liter plastic soft drink bottle went from weighing 68 grams to simply 47 grams today, representing a 31 percent reduction per bottle. That saved more than 180 million pounds of packaging in 2006 for only 2-liter soft drink bottles. The 1-gallon plastic milk jug has undergone a similar reduction, weighing 30 percent under just what it did twenty years ago.
Doing more with less helps conserve resources in another way. It will help save energy. Actually, plastics can enjoy an important role in energy conservation. Just consider the decision you’re asked to make in the food market checkout: “Paper or plastic?” Plastic bag manufacture generates less greenhouse gas and uses less freshwater than does paper bag manufacture. Not only do plastic bags require less total production energy to create than paper bags, they conserve fuel in shipping. It requires seven trucks to hold exactly the same amount of paper bags as suits one truckload of plastic bags.
Plastics also assist to conserve energy in your home. Vinyl siding and windows help cut energy consumption and reduce heating and air conditioning bills. Furthermore, the Usa Department of Energy estimates designed to use of plastic foam insulation in homes and buildings each year could save over 60 million barrels of oil over other kinds of insulation.
A similar principles apply in appliances like refrigerators and air conditioners. Plastic parts and insulation have helped to improve their energy efficiency by 30 to 50 % ever since the early 1970s. Again, this energy savings helps reduce your heating and air conditioning bills. And appliances run more quietly than earlier designs that used other materials.
Recycling of post-consumer plastics packaging began in early 1980s as a result of state level bottle deposit programs, which produced a regular source of returned PETE bottles. With adding HDPE milk jug recycling within the late 1980s, plastics recycling continues to grow steadily but in accordance with competing packaging materials.
Roughly 60 % of the U.S. population-about 148 million people-get access to a plastics recycling program. Both the common kinds of collection are: curbside collection-where consumers place designated plastics in the special bin to be picked up with a public or private hauling company (approximately 8,550 communities be involved in curbside recycling) and drop-off centers-where consumers get their recyclables to your centrally located facility (12,000). Most curbside programs collect more than one form of plastic resin; usually both PETE and HDPE. Once collected, the plastics are transported to a material recovery facility (MRF) or handler for sorting into single resin streams to boost product value. The sorted plastics are then baled to lower shipping costs to reclaimers.
Reclamation is the next step in which the plastics are chopped into flakes, washed to get rid of contaminants and sold to finish users to produce new products such as bottles, containers, clothing, carpet, transparent pvc compound, etc. The amount of companies handling and reclaiming post-consumer plastics today is over 5 times in excess of in 1986, growing from 310 companies to 1,677 in 1999. The quantity of end ways to use recycled plastics keeps growing. The government and state government along with many major corporations now support market growth through purchasing preference policies.
At the outset of the 1990s, concern within the perceived reduction of landfill capacity spurred efforts by legislators to mandate using recycled materials. Mandates, as a method of expanding markets, may be troubling. Mandates may fail to take health, safety and gratification attributes into consideration. Mandates distort the economic decisions and can cause sub optimal financial results. Moreover, they are not able to acknowledge the life cycle benefits associated with alternatives to the environment, for example the efficient utilization of energy and natural resources.
Pyrolysis involves heating plastics within the absence or near shortage of oxygen to get rid of along the long polymer chains into small molecules. Under mild conditions polyolefins can yield a petroleum-like oil. Special conditions can yield monomers for example ethylene and propylene. Some gasification processes yield syngas (mixtures of hydrogen and deadly carbon monoxide are known as synthesis gas, or syngas). Contrary to pyrolysis, combustion is definitely an oxidative process that generates heat, carbon dioxide, and water.
Chemical recycling is a special case where condensation polymers for example PET or nylon are chemically reacted to produce starting materials.
Source ReductionSource reduction is gaining more attention as an important resource conservation and solid waste management option. Source reduction, known as “waste prevention” is defined as “activities to lower the amount of material in products and packaging before that material enters the municipal solid waste management system.”