In this modern age we have numerous man made materials and more commonly used in our everyday lives, man made plastic materials. Almost all modern day plastics are derived from petroleum and can have negative effects on not only on our enviroment but also on our body’s. Kevlar is one of these man made plastics and it has many benefits but also many faults. Do kevlar’s benefits out way its faults? Are these benefits sometimes used to disguise the many problems with this product? Kevlar with its harmful and beneficial side effects have been discussed since the products was first introduced.
Kevlar was first synthesized in 1964 by Stephenie Kwolek in Wilmongton, USA. This products is formed by combining Phenylendiamine and Terephthaloylchlor, the product of bonding these two togetehr is a aromatic polyamide. Kevlar is made up of basic units of monomer bringing together trans conformations. This provides a naturally occuring parallel structure that is ideal to turn into fibers. This product is used in an array of items including underwater cables, brake linings, spaceships, parachutes, ...
In comparing micro-leakage of resin-modified glass-ionomers (RMGI), flowable composite liners, and no liners, it was found that by applying a RMGI liner before placing the composite decreased the extent of micro-leakage3. By doing this, the farthest the micro-leakage occurred was to the cervical wall, whereas with composite liners and no liners there was leakage to the cervical wall and into the axial wall3. The reason for the difference could be attributed to the bond between the glass ionomer and composite. This bond is weak and can be thought of as an unbounded wall, leading to less shrinkage stress to the bonds between composite and dentin3.
In 105 CE a man named Cai Lun during the Eastern Han Dynasty invented the paper from worn fishnet, bark and cloth. These materials were used because they could be easily found at a low price compared to Hemp fiber and silk. Hemp fiber and silk were used at first but then the Chinese realized there are greater uses for this material. Therefore they started to use the worn fishnet, bark and
Service life The effect of fillers on polymers is that they are very beneficial because they don’t get ruined for a long time. Glass fillers are the most commonly used fillers in polymers. This is because they last longer and their service life is longer.
Today, polyvinyl chloride (PVC) is used in many different products across the world. According to the APHA (2011), the material can be found in toys, medical supplies, floors, and even food wrapping. (p. 1) I believe that this material has made it possible for a lot of products to be made that have benefited the human population, but I believe there are many drawbacks to using this material.
The most common form of polyethylene is petroleum based or olefins based; as before mentioned polyethylene compounds have a wide commercial applicability and are made from non-renewable resources (Harding, Dennis, von Blottnitz, Harrison, & S.T.L., 2007). Its manufacturing processes are regarded as energy intensive and release significant amount of CO2 and heat into the atmosphere (Broderick, 2008). Next a little more detailed description of polyethylene’s production processes will be presented, with a focus on the way the material inputs are extracted and synthesized.
The. Although viscose rayon was originally called “artificial silk,” it is not truly synthetic. fiber, as it is made from wood pulp, a naturally occurring, cellulose-based material. Nylon however, is a synthetic fiber. It is a polyamide whose molecular chains are formed regularly.
Today’s unprecedented technological advancement has accelerated the pace at which everyone is living. Time becomes a limited resource that every person tries to make the most use of. Therefore, convenience is the major quality highly valued in today’s world. Plastics strongly demonstrate such quality; plastics are light-weighted and disposable. Consequently, the use of plastics is prevalent, from simple objects, such as bags and bottles, to more complex components, such as computer boards. The benefits of plastics are countless; for instance, plastics are disposable and waterproof. However, many critics have raised questions regarding the threats posed by phenomenal plastics. What are the downsides of plastics? How should we cope with the plastic pollution around the globe? Susan Beraza has the answers to
early 1990’s, no such material was known. In 1991, carbon nanotubes were discovered. Although not
We have all heard the excuses before, "It's uncomfortable, I'm only going around the corner", I'd rather be thrown out of a car than be stuck in a seatbelt," and my favorite, "I'm a good driver I don't need to wear one." Well you may be a good driver but there are situations beyond your control such as bad weather, road conditions and not to mention other drivers that can affect your safety. Seat belts can mean the difference between life and death in an auto accident. Wearing a seat belt every time you enter a vehicle is not only the smart thing to do it is the right thing because it saves lives, it's the law and it will save you money.
German Chemist Hans von Pechmann first synthesized Polyethylene by accident in 1898 by heating diazomethane. His colleagues characterized the waxy substance polyethylene due to the fact that they recognized that it consisted of long ethene chains. It was then first industrially synthesized by accident in 1933 by applying extremely high pressure to ethylene and benzaldehyde. Over the years, development of polyethylene has increased due to the additions of catalyst. This makes ethylene polymerization possible at lower temperatures and pressures.1
Joseph F. Ackerman, Newport, Ky., and John F. Jones, US Patent No. 2,923,692, Mucilaginous composition comprising salt of cross linked carboxylic polymer and method of preparing same, (Feb. 2, 1960).
Marcus, Miriam. “Ten Plastic Surgical Risks You Need To Know.” Forbes, n.p. 10 October 2007. Web. 17 February 2012.
Although companies across the globe continue to produce multiple polycarbonate #7 plastic products with BPA, more is being noticed about the adverse health effects to humans can be harmful. Testing on mice has proven that some exposure to BPA can be linked to Cancer and neurological disorders. In countries which have banned the use of BPA in different products, would agree that this chemical is toxic and dangerous. However, as long countries like the United States, who do not currently support banning BPA countrywide due to limited scientific data to back all claims, BPA will continue to be a global issue which continues to be hidden in the dark and a mystery globally
Typically when having surgery done, people will weigh the risk of the surgery against against the suspected health improvement. However, when having cosmetic surgery done, there is no health improvement. There is actually no improvement at all except to the patients mental views on themselves. There are many risks when having plastic surgery that are often overlooked by patients because the surgery is being preformed by doctors. Doctors aren’t here to harm us, but heal us, so having a certified person in a white coat cut you open to put implants in you, could’t be harmful could it? Unfortunately, it easily could. “It’s well known that breast implants of many types can cause burning pain, loss of sensation, hardening of breast tissue and serious infection. One woman who suffered complications from implants has filed a petition with the Scottish government urging adoption of such a ban. An argument could even be made that aesthetic surgery violates the Hippocratic oath [taken by medical doctors] because it carries a potential for harm without curing or preventing disease.”(Edmonds) A French company named Poly Implant Prosthese (PIP) is known for having faulty breast implants. The PIP’s are known to rupture more easily and are full of an industrial grade of silicone that was never intended for use in the medical
used to make products such as plastic lumber, toys, containers, carpet, fiber fill for jackets