Plastics are man-made materials that can be shaped into almost any form. They are one of the most useful materials ever created. Our homes, schools, and businesses are filled with plastic products. Imagine cars without synthetic bumpers, dashboards, steering wheels and switches; medicine without plastic hypodermic syringes and artificial hip joints. And what about telecommunications, dependent on plastic telephones, circuit boards and cable insulation. Our entertainment and leisure relies on the unique combination of characteristics offered by plastics in sports equipment and clothing, CDs, video and audio tape, television and cinema.
Most plastics are lightweight, flexible, durable and often colorful. They are resistant to chemicals, have hygienic surfaces, and provide insulation from electricity or heat. There are many types of plastics, each exhibiting some of these properties and characteristics. They also have their own individual strength and weaknesses. For example, the characteristic strength of nylon is well suited to producing clothing, fishing line or machine bearings, whereas if you tried to use the plastic Bakelite for the same function you would find it quite useless.
To understand how plastics are made, it is helpful to know something about the chemistry of polymers. The polymers in plastics are made up of small molecules called monomers. Most of these molecules are composed of carbon, hydrogen, nitrogen, and oxygen atoms. Some include chlorine, fluorine, silicon, or sulfur atoms. A polymer chain consists of hundreds, thousands, or even millions of monomer links. In some polymers, these links are made up of the same kind of monomer, repeated over and over again. Others are composed of two or more kinds of monomers, which may be linked randomly or in alternating sequences. In some polymers, blocks of one kind of monomer are joined to blocks of another kind.
Generally, plastics can be classified as either thermoplastics or thermosetting plastics.
With the ending of an era by means of World War 1, World War 2 was rounding the corner. ... Plastic surgery became more and more prominent during the 1960's. ... The 1980's plastic surgery became popular in the public eye. ... The 1990's put plastic surgery into a whole new realm. ... Plastic surgery was everywhere. ...
In an article on October 29, 2007 issue of Blast Magazine, Jack Bell says and I quote plastic generates toxic emissions and pollutants that contribute to global warming. 2. ... Most of us think using the same bottle again helps the environment as well as saves us money, but it may be costing us our health. 2. ... According to the "Time Magazine ", Bryan Walsh states this toxin might be linked to a variety of diseases, such as cancer and reproductive problems. 2. ... The Natural Resources Defense Council (NRDC) recommends writing to producers to display information about whe...
Plastic Toxicity Starting in the early nineteen- nineties research on plastic toxicity began to increase and more scientists and students began looking into plastic toxicity. ... Organizations that have looked into plastic toxicity Over the past years companies have started to recognize plastic toxicity more than they have before. ... One press release written by the EPA states that if DEHA is used properly it does not pose a health hazard: Recent articles in the press have alleged that di(2-ethylhexyl)adipate (DEHA) - a plasticizer used in some food wrap products - may pose a health h...
Plastic bags cost grocery stores under 2 cents per bag whereas paper bags cost 4-6 cents each (Mieszkowski). ... As termed by Lisa Kaas Boyle, a writer for Plastic Pollution Coalition, plastic bags have infamously become known as the Urban Tumbleweed (Boyle). ... In a Northern Pacific area where ocean currents collide about 1000 miles off the coast of California, there is a swirling mass of plastic debris including fragments of plastic bags 2 times the size of Texas. 50 or 60 years ago, there was no plastic out there (Mieszkowski). ... Billions of plastic bags are used in the US every year and...
Not only does plastic now replace materials such as metal, glass, ceramics, wood, and paper in a wide variety of ways, there are new roles which only plastic can fill. ... Plastic was first made in 1869 when John W. ... Polymers are converted into plastic products in many ways. ... Recycling is the main option to manage plastic waste. The five stages in the recycling of plastics are: 1. disposal by the user 2. collection by a local authority or company 3. sorting into single types of plastic 4. cleaning and removal of labels, dirt, and contents residue 5. re-processing into granules ...
Plastic Surgery Living in a society where everyone is practically judged by image, why do some people question the assets behind plastic surgery? ... Botox injections are another popular type of plastic surgery. ... This basically causes the muscle to be paralyzed indefinitely. (2 http://people.howstuffworks.com/botox1.htm) A 37 year old woman from New Jersey decided to have botox injections to get rid of her "crows feet wrinkles." ... Another common plastic surgery is a breast augmentation. ... Women are not the only ones who are entitled to plastic surgery. ...
Use of plastic bags becomes a part of our daily life. ... Plastic bags were first introduced in 1997. ... Australia uses around 4 billion plastic bags in a year, and about 2-3% get recycled (Ginis 91). ... We are using millions and billions of plastic bags each years, so where do this plastic bags end up? ... Bangladesh was the first nationwide to ban plastic bags. ...
The Purpose of this Report This report relates to the properties and design of the Butterfly Sprinkler made of 4 components, including; thermoset plastic housing, thermoset plastic spinning head, nickel plated brass pin and a stainless steel ball bearing. This report will research the materials, and the mechanical forces and stresses related to the main thermoset plastic housing and the nickel plated brass axel. ... Composition Physical data Mechanical data Price Copper Cu: 57.0 – 59.0 % Density: 8.44 g/cm^3 Tensile strength: >500 N/mm^2 $5-$20/kg Lead Pb: 25 – 35 % Elect. ... As ...