Monday, May 10, 2010
What exactly is a plastic? What are the different kinds of plastics? How are each type of plastic recycled? How can plastic waste be turned into energy? Can plastic be harmful to our health and the environment? Does continuous heavy disposal of plastic contribute to global warming? Plastic plays a big part of our everyday lives here in North America. Let’s examine some uses of plastics and how we can all play a part in recycling plastic.
Types of Plastic:
Today plastics are used in thousands of products ranging from computers, automobile parts and important medical equipment, to toys, cookware, sports equipment, and even clothes. And the plastics industry continues to grow rapidly. Just where do plastics come from? Plastic is one form of polymers that are composed of a long chain or line of smaller molecules that are known as monomers. Monomers themselves are made of atoms that are usually extracted from natural or organic substances, and are generally classified as petrochemicals. All sorts of monomers can be utilized in the creation of plastic. Crude oil and natural gas are often the source of some of these elements, which include monomers such as styrene, vinyl chloride, and vinyl acetate. Plastic products, plus hundreds of the other products we take for granted, are made from petrochemicals. One of the main ingredients in petrochemicals is oil. For example, In the United States, 10 percent of the petroleum consumption goes to make plastic. As you can see the North American appetite for oil goes beyond filling our vehicles. We need oil to manufacture plastics, which are a major part of our modern lifestyle. There are different types of plastics for different products and applications and the process in plastic manufacturing varies.
There are many types of plastic in common use. Plastic must be sorted by type for recycling since each type melts at a different temperature and has different properties. The plastics industry has developed an identification system (or identification codes) to label the different types of plastic. The identification system divides plastic into seven distinct types and uses a number code generally found on the bottom of containers.
Polyethylene terephthalate (commonly abbreviated PET) is one of the common types of plastic. It is type #1 for recycling purposes. It is a thermoplastic polymer resin of the polyester family and is used in beverage, food and other liquid containers, thermoforming applications, and engineering resins often in combination with glass fiber. PET Plastics are generally clear, tough and are a good barrier to gas and moisture. PET also has a good resistance to heat. PET Plastics are a good choice for product packaging because of its many desirable favorable characteristics. PET is available in a wide range of colors shapes and sizes. PET is highly resistant to dilute acids, oils, and alcohols. PET is a recyclable polymer that can be successfully recycled and used in many applications, meaning that virgin material does not have to be produced.
High Density Polyethylene (HDPE) is plastic type # 2. Common uses of HDPE include detergent bottles, milk jugs, and grocery bags. Most curbside recycling programs accept rigid narrow neck containers.
Polyvinyl Chloride (PVC) is plastic type #3. Common uses include plastic pipes, outdoor furniture, shrink-wrap, water bottles, salad dressing and liquid detergent containers. Recycling centers almost never take #3 plastic.
Low Density Polyethylene (LDPE) is plastic type #4. Common uses: dry cleaning bags, produce bags, trash can liners and food storage containers. Some recycling centers that accept HDPE (#2) also accept LDPE (#4) bags.
Polypropylene (PP) is plastic type #5. Common uses: aerosol caps, drinking straws. This type of plastic is seldom recycled.
Polystyrene (PS) or Styrofoam is plastic type #6. Common uses include packaging pellets or peanuts, cups, plastic tableware, meat trays, and to-go containers. Many shipping/packaging stores will accept polystyrene peanuts and other packaging materials for reuse. Cups, meat trays, and other containers that have come in contact with food are more difficult to recycle
Other types of plastics are considered type #7. Common uses include certain kinds of food containers and Tupperware. This plastic category is any plastic other than the named #1-#6 plastic types. These containers can be any of the several different types of plastic polymers. Recycling centers do not take plastic #7.
Many types of plastic can be recycled. One huge example is plastic shopping bags. Plastic shopping bags revolutionized how people shop for food and essentials. They are everywhere we shop. Over a million plastic bags are consumed per minute, worldwide. How to we recycle plastic bags and cut down on waste? Many organizations have programs in place to recycle plastic bags. Many retail outlets offer an at-store collection program for plastic shopping bags. This means that shoppers can bring back their bags to these retail locations so they can be recycled. You can also use them the second time around for household use, for example, using them in a trash container. Buy or make a couple of cloth bags and say no to plastic carrier bags in the future. Certainly the 3Rs “reduce, reuse and recycle” should be practiced by all in relation to plastic bags.
Another common use for plastic is for beverage containers. Much of our soda pop, juice, water, milk and other drinks come in plastic. Unfortunately a lot of these plastic containers are thrown in garbage bins, and even on the ground and waterways. An irony today, is that due to polluted water caused by pollution, we are drinking more bottled water than ever before. The majority of this bottled water comes in plastic containers. It is tragic that tap water is no longer fit to drink in many parts of North America. Therefore, more plastic is needed to keep up with the ever-increasing demand of bottled water. Many of these plastics can be further recycled, depending on the type of plastic. There have been reported health risks from plastic beverage containers, so we need to consume beverages in them in moderation. This would not only prevent possible human health issues, but also would cut down on plastic containers in landfills and help our environment and even offset global warming.
A lot of the foods we purchase come in plastic containers. Whether it is microwave dinners, pasta, and other foods, they are put in plastic, ready to be put into the microwave. Many fast food restaurants use plastic to serve food in to customers. Unfortunately most of these types of plastic containers are not recyclable and end up being disposed of as plastic waste. We should attempt to reuse and recycle these types of plastics when possible.
Most of our health and beauty products come in plastic. Cosmetics, such as lipsticks, and other beauty items come in plastics. Shampoo, dental products, and hair and body products come in plastics. Most of these types of plastics eventually end up as plastic waste as well. Many containers including garbage cans, totes, hampers, and other large containers are made from plastic. Recycling containers and recycling bins are often made of plastic. Automobiles, trucks, boats and other vehicles have a large amount of plastic in them. Plastic is used in parts of a vast array of other consumer items.
Most electronic devices such as televisions, computers, stereos and computer peripherals are housed in plastic casings. These products are even wrapped in plastic when you purchase them new. Most of the toys we purchase for our children for Christmas are made of plastic. Unfortunately when we get tired of these items or they wear out, they end up in landfills and cause environmental damage. Also take into account that most consumer items we purchase are paid for with plastic whether it be a credit card or debit card. Most of us have many consumer loyalty plastic cards as well. When these cards get damaged or expire they get thrown out. It may not seem like a lot if it is one person, but multiply the amount of plastic cards by a few billion and that is a lot of plastic going in the trash.
Plastic Recycling Obstacles:
Recycling plastics as opposed to glass or metallic materials, poses some exceptional challenges from a recycling perspective. Plastics or plastic bottles are much harder to break down, which is due to the high molecular weight of large polymer chains. Another way of stating this problem is that, since a macromolecule interacts with its environment along its entire length, its enthalpy of mixing is large compared to that of a small organic molecule with a similar structure; thermal excitations are often not enough to drive such a huge molecule into solution on their own. Due to this uncommon influence of mixing enthalpy, polymers must often be of nearly identical composition in order to mix with one another. To take representative samples from beverage containers, the many aluminum-based alloys all melt into the same liquid phase, but the various copolymer blends of PET from different manufacturers do not dissolve into one another when heated. Instead, they tend to phase-separate, like oil and water. Phase boundaries weaken an item made from such a mixture considerably, meaning that most polymer blends are only useful in a few, very limited contexts.
Another barrier to plastic recycling is the widespread use of dyes, fillers, and other additives in plastics. The polymer is generally too viscous to economically remove fillers, and would be damaged by many of the processes that could cheaply remove the added dyes. Additives are less widely used in beverage containers, plastic bottles and plastic bags, allowing them to be recycled more frequently.
The use of biodegradable plastics is slowly on the increase. Plastic recycling companies are starting to develop, however most plastic recycling to date is very little and in most places none. There is issues with recycled friendly plastics for recycling, the recycled plastic is less valuable and cannot be mixed with plastic that is not good for recycling.
Many such problems can be solved by using a more elaborate monomer recycling process, in which a condensation polymer essentially undergoes the inverse of the polymerization reaction used to manufacture it. This yields the same mix of chemicals that formed the original polymer, which can be purified and used to synthesize new polymer chains of the same type.
Part of the issue in recycling plastics is the cost. Prices for virgin resin soared, and the demand for recycled plastics increased. There are success stories in plastics recycling, nonetheless. In recent years, several plastics recycling companies have closed their doors. Soft-drink bottles, however, are one success story in plastics recycling. Of course, plastics are generally very lightweight. Putting plastics into landfills is not always the best disposal method.
Look for the number 1 or 2 in a triangular recycle symbol on the container. Only plastic #1 and #2 items with a neck are recyclable as a general rule. Recycled plastics are tomorrow's commercial materials, available today. Coupled with this increased consumer participation is a rising interest in the commercial applications of recyclable plastics. Energy concerns have drawn attention to used plastics as an alternative source of energy for industry. One reason that a greener plastics industry is possible is the thermoplastic elastomers. Plastic scrap recycling began with the PET in plastic soda bottles and the HDPE found in milk jugs in part because these plastics are able to be cleaned, broken-down, and returned to the thermoplastic elastomers can be recycled at every stage in the manufacturing and use- cycle. At the plastic recycling company, scrap pieces can be cleaned, melted down and put back into the supply; at home, consumers can clean out their soda bottles and participate in a community scrap recycling program which reclaims the plastics for another cycle of use
Biodegradable plastic is a degradable plastic in which the degradation results from the action of naturally occurring microorganisms such as bacteria, fungi, and algae. Hydro-biodegradable plastics tend to degrade and biodegrade somewhat more quickly than oxo-biodegradable ones but the end result is the same both are converted to carbon dioxide, water and biomass. Degradable Plastic are plastics designed to undergo a significant change in its chemical structure under specific environmental conditions resulting in a loss of some properties that may vary as measured by standard test methods appropriate to the plastic and the application in a period of time that determines its classification. This results in their physical disintegration and a drastic reduction in their molecular weights. No toxic by-products are known to result from PHB or PHV. With a little bit of care much plastic can be recycled, and collection of plastics for recycling is increasing rapidly.
Plastics Impact on Health and Environment:
Plastics are the fastest growing component of the waste stream. Plastic does not biodegrade in the natural environment. When littered, items that had been designed for useful life of minutes at most, many of these plastics degrade the environment for a lifetime as litter. Plastic litter has killed thousands of marine birds and mammals and threatens endangered species like sea turtles that mistake them for food. Plastics have historically suffered from a low recycling rate.
Although plastics have had a remarkable impact on our culture, it has become increasingly obvious that there is a price to be paid for their use. In the western world plastic plays a part in our everyday life and most of that plastic gets discarded as plastic waste. These wastes may pose a potential hazard to the human health or the environment (soil, air, water) when improperly treated, stored, transported or disposed off or managed.
The material used in bottled water – a thermoplastic polymer known as PET – can take hundreds of years to break down in a landfill. Recycling doesn't capture all the empties.
Plastic waste in the oceans poses a potentially devastating long-term toxic threat to the food chain, according to marine scientists. Studies suggest billions of microscopic plastic fragments drifting underwater are contributing to pollutants.
PVC is a commonly used type of plastic found in baby shampoo bottles, packaging, saran wrap, shower curtains and thousands of other products—yet there is very little public awareness of its serious health and environmental dangers. PVC is the most harmful type of plastic. In the United States as much as 7 billion pounds of PVC are discarded every year. PVC disposal is the largest source of dioxin-forming chlorine and phthalates in solid waste as well as a major source of lead, cadmium and other toxins–which pose serious health hazards. PVC production poses serious environmental health threats due to the manufacture of raw chemicals, including chlorine and cancer-causing vinyl chloride monomer. PVC includes high amounts of toxic additives, which are released during use and disposal, resulting in elevated human exposures to chemicals. Disposing of PVC in landfills poses long-term problems of toxic additives getting into groundwater. When burned, PVC plastic forms dioxins, a highly toxic group of chemicals that build up in the food chain, can cause cancer and harms the immune and reproductive systems. PVC is very difficult to recycle because many additives used in PVC products make it impossible to retain.
Bisphenol A is another dangerous type of plastic. Adults exposed to higher amounts of the plastic compound bisphenol A are more likely to be afflicted by cardiovascular disease, type-2 diabetes, and have liver enzyme abnormalities, according to a study by the Journal of the American Medical Association. Those with high levels of the BPA type of plastic had nearly three times the odds of developing heart disease and 2.4 times the odds of diabetes, compared to people will low exposures. Biphenyl A is a hormone disruptor. Studies have linked low-dose BPA exposure with such effects as: permanent changes to genital tract; increase prostate weight; decline in testosterone; breast cells predisposed to cancer; prostate cells more sensitive to hormones and cancer; and hyperactivity.
Bisphenol A, a chemical that doesn't occur in nature and is derived from petroleum, is commonly made into plastic, and companies frequently used it in consumer products such as beverage containers. It has since become one of the highest volume chemicals, with annual output of more than 3 million tonnes. Besides its food contact use, it is found in a ton of applications in such products as food wrap, cars, sports helmets and DVDs
What is Being Done on Plastic Reduction and Recycling?
Some countries as well was local municipalities are taking steps to reduce the amount of plastic in our landfills and incinerators. The city of Toronto, Canada is considering tough action to curb waste generated by overly packaged consumer products. From an outright ban on materials used in food takeout to a tax on retail plastic bags to city-run deposit-return programs, Toronto is considering many options. Other Canadian municipalities have moved on specific products, such as a recent bottled-water ban at city-owned buildings in London, Ontario. Many jurisdictions have implemented deposits on soft drinks and juice at the retail level to encourage consumers to return plastic bottles to recycling depots for a refund. In the United States, Seattle recently banned plastic foam in food packaging, with an alternative suitable for composting to be in place by 2010. San Francisco became the first city in North America to ban the use of traditional plastic grocery bags in 2007, a step that municipal leaders hope will spread across the country. In most parts of Switzerland throwing away rubbish costs money - each rubbish bag has to have a sticker on it and each sticker costs at least one euro (60 pence). Plastic PET bottles are the most common drinks containers in Switzerland, and 80% of them are recycled - far higher than the European average of 20 to 40%. These are a few examples of governments getting involved to entice people to recycle plastic. We need to all play a part to keep plastic out of landfills. We are paying the price to live a convenient lifestyle. We seem to live a disposable society. If we want to offset global warming and reduce pollution and toxins going into the environment we need to make adjustments to our lifestyle. The term “reduce reuse and recycle” certainly applies to plastic.