This is made to lend an improved understanding concerning how plastics are produced, the different kinds of plastic and their numerous properties and applications.
A plastic is a form of synthetic or man-made polymer; similar in many ways to natural resins found in trees along with other plants. Webster’s Dictionary defines polymers as: any kind of various complex organic compounds produced 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 past of manufactured plastics dates back more than a hundred years; however, when compared with other materials, plastics are relatively modern. Their usage in the last century has enabled society to make huge technological advances. Although plastics are looked at as an advanced invention, there have invariably been “natural polymers” like amber, tortoise shells and animal horns. These materials behaved like today’s manufactured plastics and were often used like the way manufactured plastics are now applied. As an example, ahead of the sixteenth century, animal horns, which become transparent and pale yellow when heated, were sometimes utilized to replace glass.
Alexander Parkes unveiled the very first man-made plastic in the 1862 Great International Exhibition inside london. This product-that was dubbed Parkesine, now called celluloid-was an organic material produced by cellulose that when heated might be molded but retained its shape when cooled. Parkes claimed that it new material could do anything that rubber was effective at, yet for less money. He had discovered a material that might be transparent in addition to carved into a large number of different shapes.
In 1907, chemist Leo Hendrik Baekland, while striving to generate a synthetic varnish, came across the formula for the new synthetic polymer caused by coal tar. He subsequently named the newest substance “Bakelite.” Bakelite, once formed, could stop being melted. Due to its properties being an electrical insulator, Bakelite was utilized in producing high-tech objects including cameras and telephones. It was also found in producing ashtrays and as an alternative for jade, marble and amber. By 1909, Baekland had coined “plastics” because the term to explain this completely new class of materials.
The 1st patent for pvc granule, a substance now used widely in vinyl siding and water pipes, was registered in 1914. Cellophane had also been discovered during this period.
Plastics did not really pull off until right after the First World War, with the aid of petroleum, a substance much easier to process than coal into raw materials. Plastics served as substitutes for wood, glass and metal through the hardship times during the World War’s I & II. After World War II, newer plastics, like polyurethane, polyester, silicones, polypropylene, and polycarbonate joined polymethyl methacrylate and polystyrene and PVC in widespread applications. More would follow and also the 1960s, plastics were within everyone’s reach because of the inexpensive cost. Plastics had thus come to be considered ‘common’-an expression in the consumer society.
Considering that the 1970s, we have now witnessed the advent of ‘high-tech’ plastics used in demanding fields such as health 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 at all levels. Plastics are used in such a variety of applications since they are uniquely capable of offering numerous properties that offer consumer benefits unsurpassed by other materials. They are also unique because their properties can be customized for each individual end use application.
Oil and gas are the major raw materials utilized to manufacture plastics. The plastics production process often begins by treating parts of oil or natural gas in the “cracking process.” This method contributes to the conversion of those components into hydrocarbon monomers such as ethylene and propylene. Further processing results in a wider selection of monomers such as styrene, rigid pvc compound, ethylene glycol, terephthalic acid and many others. These monomers are then chemically bonded into chains called polymers. The numerous mixtures of monomers yield plastics with a wide range of properties and characteristics.
PlasticsMany common plastics are manufactured 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 frequent instances of these. Below is actually a diagram of polyethylene, the easiest plastic structure.
Even though the basic makeup of several plastics is carbon and hydrogen, other elements can be involved. Oxygen, chlorine, fluorine and nitrogen may also be located 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 separated into two distinct groups: thermoplastics and thermosets. The vast majority of plastics are thermoplastic, meaning that after the plastic is formed it may be heated and reformed repeatedly. Celluloid is really a thermoplastic. This property permits easy processing and facilitates recycling. Another group, the thermosets, cannot be remelted. Once these plastics are formed, reheating will cause the fabric to decompose rather than melt. Bakelite, poly phenol formaldehyde, is a thermoset.
Each plastic has very distinct characteristics, but many plastics get the following general attributes.
Plastics can be very resistant against chemicals. Consider every one of the cleaning fluids in your home that happen to be packaged in plastic. The warning labels describing what goes on when the chemical enters into experience of skin or eyes or is 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 may be both thermal and electrical insulators. A stroll via your house will reinforce this concept. Consider each of the electrical appliances, cords, outlets and wiring which can be made or engrossed in plastics. Thermal resistance is evident in the kitchen 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 is made of polypropylene as well as the fiberfill in several winter jackets is acrylic or polyester.
Generally, plastics are extremely light in weight 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 others sink. But, when compared to density of stone, concrete, steel, copper, or aluminum, all plastics are lightweight materials.
Plastics can be processed in different methods to produce thin fibers or very intricate parts. Plastics can be molded into bottles or elements of cars, including dashboards and fenders. Some pvcppellet stretch and therefore are very flexible. Other plastics, for example polyethylene, polystyrene (Styrofoam™) and polyurethane, may be foamed. Plastics could be molded into drums or even be mixed with solvents to be adhesives or paints. Elastomers and some plastics stretch and therefore are very flexible.
Polymers are materials by using a seemingly limitless variety of characteristics and colors. Polymers have many inherent properties that may be further enhanced by a wide range of additives to broaden their uses and applications. Polymers can be created to mimic cotton, silk, and wool fibers; porcelain and marble; and aluminum and zinc. Polymers may also make possible products which do not readily range from natural world, like clear sheets, foamed insulation board, and flexible films. Plastics may be molded or formed to create many kinds of items with application in lots of major markets.
Polymers are usually manufactured from petroleum, although not always. Many polymers are created from repeat units produced from gas or coal or crude oil. But foundation repeat units can often be made from renewable materials for example polylactic acid from corn or cellulosics from cotton linters. Some plastics have invariably been made from renewable materials like cellulose acetate employed for screwdriver handles and gift ribbon. As soon as the building blocks can be created more economically from renewable materials than from standard fuels, either old plastics find new raw materials or new plastics are introduced.
Many plastics are combined with additives as they are processed into finished products. The additives are incorporated into plastics to alter and boost their basic mechanical, physical, or chemical properties. Additives are utilized to protect plastics from your degrading negative effects of light, heat, or bacteria; to modify such plastic properties, including melt flow; to offer color; to provide foamed structure; to supply flame retardancy; and to provide special characteristics for example improved surface appearance or reduced tack/friction.
Plasticizers are materials incorporated into certain plastics to improve flexibility and workability. Plasticizers are located in numerous plastic film wraps as well as in flexible plastic tubing, both of which are normally utilized in food packaging or processing. All plastics found in food contact, for example the additives and plasticizers, are regulated through the U.S. Food and Drug Administration (FDA) to make certain that these materials are safe.
Processing MethodsThere are a couple of different processing methods utilized to make plastic products. Listed here are the four main methods where plastics are processed to produce the items that consumers use, for example plastic film, bottles, bags and other containers.
Extrusion-Plastic pellets or granules are first loaded in a hopper, then fed into an extruder, which is actually a long heated chamber, whereby it is moved by the act of a continuously revolving screw. The plastic is melted by a mix of heat from the mechanical work done and also by the new 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 from the die, it can be cooled by air or water. Plastic films and bags are created by extrusion processing.
Injection molding-Injection molding, plastic pellets or granules are fed from your hopper in to a heating chamber. An extrusion screw pushes the plastic through the heating chamber, where the material is softened in to a fluid state. Again, mechanical work and hot sidewalls melt the plastic. At the end of this chamber, the resin is forced at high-pressure in a cooled, closed mold. Once the plastic cools to some solid state, the mold opens and also the finished part is ejected. This technique is used to help make 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 form, extrusion blow molding, the die forms a continuous semi-molten tube of thermoplastic material. A chilled mold is clamped around the tube and compressed air is going to be blown into the tube to conform the tube towards the interior from the mold as well as solidify the stretched tube. Overall, the aim is to generate a uniform melt, form it in to a tube with all the desired cross section and blow it to the exact model of the item. This process is commonly used to manufacture hollow plastic products and its particular principal advantage is its ability to produce hollow shapes without needing to join several separately injection molded parts. This procedure is utilized to produce items including commercial drums and milk bottles. Another blow molding strategy is to injection mold an intermediate shape called a preform and after that to heat the preform and blow the heat-softened plastic to the final shape within a chilled mold. This is the process to help make carbonated soft drink bottles.
Rotational Molding-Rotational molding is made up of closed mold mounted on a machine effective at rotation on two axes simultaneously. Plastic granules are positioned inside the mold, which can be then heated within an oven to melt the plastic Rotation around both axes distributes the molten plastic into a uniform coating on the inside of the mold up until the part is placed by cooling. This procedure is utilized to help make hollow products, for example large toys or kayaks.
Durables vs. Non-DurablesAll kinds of plastic products are classified throughout the plastic industry to be either a durable or non-durable plastic good. These classifications are employed to reference a product’s expected life.
Products with a useful lifetime of 36 months or even more are referred to as durables. They include appliances, furniture, consumer electronics, automobiles, and building and construction materials.
Products by using a useful life of below 3 years are generally referred to as 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 possesses good gas and moisture barrier properties rendering it ideal for carbonated beverage applications as well as other food containers. The reality that it has high use temperature allows so that it is employed in applications including heatable pre-prepared food trays. Its heat resistance and microwave transparency make it an excellent heatable film. In addition, 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 commonly used for a lot of packaging applications mainly because it provides excellent moisture barrier properties and chemical resistance. However, HDPE, like all kinds of polyethylene, is limited to individuals food packaging applications that do not require an oxygen or CO2 barrier. In film form, HDPE is commonly used in snack food packages and cereal box liners; in blow-molded bottle form, for milk and non-carbonated beverage bottles; and in injection-molded tub form, for packaging margarine, whipped toppings and deli foods. Because HDPE has good chemical resistance, it really is used for packaging many household as well as industrial chemicals including 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 might be broadly split up into rigid and flexible materials. Rigid applications are concentrated in construction markets, consisting of 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 is 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 due to its toughness, flexibility and transparency. LDPE has a low melting point so that it is popular for use in applications where heat sealing is important. Typically, LDPE is utilized to produce flexible films including those useful for dry cleaned garment bags and create bags. LDPE is likewise accustomed to manufacture some flexible lids and bottles, in fact it is commonly used in wire and cable applications due to its stable electrical properties and processing characteristics.
Polypropylene (PP) has excellent chemical resistance and it is popular in packaging. It comes with a high melting point, so that it is perfect for hot fill liquids. Polypropylene is located in anything from flexible and rigid packaging to fibers for fabrics and carpets and large molded parts for automotive and consumer products. Like other plastics, polypropylene has excellent potential to deal with 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 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 vital, as with medical and food packaging, in laboratory ware, and in certain electronic uses. Expandable Polystyrene (EPS) is normally extruded into sheet for thermoforming into trays for meats, fish and cheeses and into containers like egg crates. EPS is likewise directly formed into cups and tubs for dry foods such as dehydrated soups. Both foamed sheet and molded tubs are used extensively in take-out restaurants for his or her lightweight, stiffness and ideal thermal insulation.
If you are conscious of it or perhaps not, plastics play an important part in your lifetime. Plastics’ versatility permit them to be employed in anything from car parts to doll parts, from soft drink bottles towards the refrigerators they can be held in. From the car you drive to operate within the television you watch in your house, plastics make your life easier and. Now how will it be that plastics have become so widely used? How did plastics end up being the material preferred by numerous varied applications?
The straightforward solution is that plastics can offer the items consumers want and need at economical costs. Plastics hold the unique power to be manufactured to fulfill very specific functional needs for consumers. So maybe there’s another question that’s relevant: What do I want? No matter how you answer this, plastics often will suit your needs.
If your product is made of plastic, there’s grounds. And odds are the key reason why has everything with regards to helping you, the individual, get what you need: Health. Safety. Performance. and Value. Plastics Have The Ability.
Just take into account the changes we’ve noticed in the food store in recent times: plastic wrap assists in keeping meat fresh while protecting it in the poking and prodding fingers of your own fellow shoppers; plastic bottles mean you could lift an economy-size bottle of juice and must 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 several of the big-ticket things you buy. Plastics help make portable phones and computers that really are portable. They assist major appliances-like refrigerators or dishwashers-resist corrosion, last longer and operate better. Plastic car fenders and the entire body panels resist dings, so you can cruise the food market parking area with certainty.
Modern packaging-including heat-sealed plastic pouches and wraps-helps keep food fresh and clear of contamination. This means the resources that went into producing that food aren’t wasted. It’s the exact same thing once you have the food home: plastic wraps and resealable containers maintain your leftovers protected-much to the chagrin of kids everywhere. Actually, packaging experts have estimated that each pound of plastic packaging is effective in reducing food waste by as much as 1.7 pounds.
Plastics can also help you bring home more product with less packaging. For 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 create home the equivalent amount of product, 8 pounds of steel or higher 40 pounds of glass. Not only do plastic bags require less total energy to make than paper bags, they conserve fuel in shipping. It will require seven trucks to hold exactly the same variety of paper bags as fits in one truckload of plastic bags. Plastics make packaging more effective, which ultimately conserves resources.
LightweightingPlastics engineers are always working to do more with less material. Since 1977, the two-liter plastic soft drink bottle has gone from weighing 68 grams to simply 47 grams today, representing a 31 percent reduction per bottle. That saved greater than 180 million pounds of packaging in 2006 only for 2-liter soft drink bottles. The 1-gallon plastic milk jug has undergone an identical reduction, weighing 30 percent under what it really did two decades ago.
Doing more with less helps conserve resources in a different way. It can help save energy. In fact, plastics can play a tremendous role in energy conservation. Just look at the decision you’re inspired to make with the food market checkout: “Paper or plastic?” Plastic bag manufacture generates less greenhouse gas and uses less freshwater than does paper bag manufacture. Furthermore plastic bags require less total production energy to make 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 assistance to conserve energy in your home. Vinyl siding and windows help cut energy consumption and lower air conditioning bills. Furthermore, the U.S. Department of Energy estimates designed to use of plastic foam insulation in homes and buildings each and every year could save over 60 million barrels of oil over other kinds of insulation.
The same principles apply in appliances for example refrigerators and ac units. Plastic parts and insulation have helped to enhance their energy efficiency by 30 to 50 percent 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 during the early 1980s because of state level bottle deposit programs, which produced a regular availability of returned PETE bottles. With the addition of HDPE milk jug recycling within the late 1980s, plastics recycling has grown steadily but in accordance with competing packaging materials.
Roughly 60 percent in the Usa population-about 148 million people-gain access to a plastics recycling program. The 2 common sorts of collection are: curbside collection-where consumers place designated plastics inside a special bin to get gathered by a public or private hauling company (approximately 8,550 communities get involved in curbside recycling) and drop-off centers-where consumers place their recyclables to a 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 reduce shipping costs to reclaimers.
Reclamation is the next thing the location where the plastics are chopped into flakes, washed to get rid of contaminants and sold to terminate users to manufacture new services such as bottles, containers, clothing, carpet, pvc compound, etc. The quantity of companies handling and reclaiming post-consumer plastics today has ended five times greater than in 1986, growing from 310 companies to 1,677 in 1999. The amount of end purposes of recycled plastics keeps growing. The government and state government and also many major corporations now support market growth through purchasing preference policies.
Early in the 1990s, concern on the perceived lowering of landfill capacity spurred efforts by legislators to mandate using recycled materials. Mandates, as a means of expanding markets, may be troubling. Mandates may forget to take health, safety and gratifaction attributes into account. Mandates distort the economic decisions and can cause sub optimal financial results. Moreover, they are not able to acknowledge the lifestyle cycle advantages of options to the planet, like the efficient usage of energy and natural resources.
Pyrolysis involves heating plastics in the absence or near shortage of oxygen to interrupt across 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 carbon monoxide are called synthesis gas, or syngas). As opposed to pyrolysis, combustion is definitely an oxidative method that generates heat, co2, and water.
Chemical recycling can be a special case where condensation polymers including PET or nylon are chemically reacted to create starting materials.
Source ReductionSource reduction is gaining more attention as an important resource conservation and solid waste management option. Source reduction, often called “waste prevention” is defined as “activities to minimize the quantity of material in products and packaging before that material enters the municipal solid waste management system.”