basic theory of plastic
Plastic is an organic material formed from macromolecules and processed through a chemical process or through the synthesis of other materials. The word itself comes from the plastic plastikos (Greek) which means it can be formed. Plastics can be molded, cast or merged with another with relative ease. Plastic itself commercially daiam various forms of sheet, plate, film, rolls, granulat and tube with different cross-sectional shape. Polymer word first used in 1866. Previous polymers made from natural organic material of animals and plants. With a variety of chemical reactions in modified cellulose acetate cellulose, is used to for the manufacture of photographic film, sheet packing, and textile fibers. Cellulose nitrate is also converted into cellulose for plastics, explosives, rayon and varnished. The first synthetic polymer made man is phenol-formaldehyde, thermosetting type which was developed in 1906 called bakelit rian (the commercial name, Backeland LH, 1863-1944)
The development of modern plastics technology started in 1920, when the raw materials needed to manufacture the polymer material is then extracted from the tin and petroleum. Ethylene is the first example of such nentah material, and forming the polyethylene block. Ethylene is a product of the reaction between acetylen with hydrogen, while acetylen is the result of reaction between coke and methane. Similarly, polypropylene, Polyvinylchlonde, Polymethyl methacrylate, polycarbonate and others made the same way. These materials are known as synthetic organic polymer. Although in Polyethylene only Carbon and Hydrogen atoms are involved, other polymers can be combined with chlorine, Florin, sulfur, silicon, nitrogen and oxygen. The result is to make the other advantages of the respective polymers.
The reason people use plastic materials as a basic material goods / tools are:
- Easily carried or formed
- Does not conduct electricity
- Able to pull a fairly high
- Low density
- Etc.
When compared to metal, plastic has advantages and disadvantages as follows;
1. Profit
a. Mild
b. Economical in progress
c. Corrosion-resistant
d. Vibration damping
e. Low heat dissipation
f. Surface / better viewing. Recyclable (Except type termosett). Complex formation can be manufactured
2. Loss
a. Low strength
b. Low thermal resistance
c. Dimensions are not Stable
d. Easily change the properties.
e. Difficult repairs.
f. More suitable for mass production
g. For some types of polymers are still expensive.
