There were various periods in the mankind history – stone, bronze, iron ages, and they were connected with discovery of a particular material, which enabled civilization to develop in terms of consumption. One of the recent discoveries of the late 19th century, which transformed and facilitated life in the 20th and 21st centuries, is plastic.
   Initial raw material of plastic was oil. This is a chemically developed material, which after thermal processing, can be bent into all sorts of shapes. The main component of plastic is polymeric materials, i.e., large molecular compounds, which endue products with specific properties: elasticity, durability, lightness, water and frost resistance, corrosion resistance, high durability against stretching etc. Polymeric materials can be either hard or flexible; they are resistant to chemical substances. The types of polyolefin, most often used in industry, are polyethylene and polypropylene.

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