Реферат: Plastic It
Plastic: It’s Everywhere Essay, Research Paper
Everywhere you look, there it is. You simply cannot avoid it. What is it? Plastic, of course. Have you heard the ads for cotton (?It?s the fabric of our lives?)? Plastic is comparatively important. Its is the backbone of our day to day existences. Think carefully, not one day goes by without the use of a plastic product. They are so mainstream that there may be times you do not even realize that you are using one.
The very first man-made plastic was presented by one Alexander Parkes at the Great International Exhibition in London in the year 1862. The public named it Parkesine. It was derived from cellulose- once it was heated, it could be molded and then retained its shape as it cooled. Parkes said that this material was capable of everything that rubber was able to do, but cheaper. Unfortunately, investors backed out because of the very high cost of the raw materials. (History).
Celluloid was the next form of plastic to emerge. John Wesley Hyatt formed it as a replacement for ivory in billiard balls. Since raw collodion (what he first made them of) was highly explosive, the balls exploded when they hit each other. Hyatt then added camphor forming celluloid, the first thermoplastic. A thermoplastic is a substance that can be molded when heated and when pressure is applied. When both heat and pressure are removed, the substance retains its form. Celluloid was later used in photographic film and is still used on film for movies. (?History?).
Bakelite was and is a very prominent form of plastic invented by Leo Baekeland. It came out as the first completely synthetic plastic. It hardens quickly and retains the shape of the container it cools in. Once hardened, the material would not boil, melt of dissolve with common acids of solvents. Bakelite was resistant to electricity, heat-resistant, shatterproof, and would not crack, fade, crease, or become discolored. In other words, it never changed. It could be added to many materials to make them more durable. The military found this substance especially useful in making weapons lighter. (?History?).
Plastics are polymers, but are commonly known by their abbreviated or brand names. Polythylene terephthalate and polyvinyl chloride and known as PET and PVC. Foamed chloride and polymethyl methacrylates are known as Styrofoam and Plexiglas. (?Plastic?). It is rather obvious why these nicknames are better known. Would you really want to waste brain space on the real name of Styrofoam? I didn?t think so. There are basically two types of plastics- ?commodity? resins and ?specialty? resins. (?Plastic?) ?Commodity resins are plastics that are produced at high volume and low cost for the more common disposable items and durable goods?Specialty resins are plastics whose properties are tailored to specific applications and that are produced at low volume and higher cost.? (?Plastic?). Specialty resins include those used for plumbing, hardware, and cars. In these areas it is very important they be strong as they are competing with metals.
In this brief background of plastic and all its uses and forms, it becomes clear just how important it is in our daily lives. Thank to Alexander Parkes, who made a strong attempt to mainstream plastic, and John Wesley Hyatt, who made ?explosive? advances, and Leo Baekeland, who formed the virtually indestructible Bakelite, plastic is a given in today?s world. Plastic is everywhere and is by far one of the more important inventions.
?History of Plastics?.. www.ameriplas.org/benefits/about_plastics/history.html. ( March 18, 2000).
?Plastic (Thermoplastic and Thermosetting Resins)?..
www.britannica.com/bcom/eb/article/9/0,115716,115139+2,00.html. (March 18, 2000).