PLASTICS

Plastics are a large and varied group of materials consisting of combinations of carbon and oxygen, hydrogen, nitrogen, and other organic and inorganic elements. While solid in its finished state, a plastic is at some stage in its manufacture, liquid and capable of being formed into various shapes. Forming is most usually done through the application, either singly or together, of heat and pressure. There are over 40 different families of plastics in commercial use today, and each may have dozens of subtypes and variations.

A successful design in plastics is always a compromise among highest performance, attractive appearance, efficient production, and lowest cost. Achieving the best compromise requires satisfying the mechanical requirements of the part, utilizing the most economical resin or compound that will perform satisfactorily, and choosing a manufacturing process compatible with the part design and material choice.

Most people have now outgrown the impression that plastics are low-cost substitute materials. Those that still view plastics as cheap and unreliable have not kept up with developments in polymer technology for the past ten years.

Many plastics did indeed evolve as replacements for natural products such as rubber, ivory, silk or wool, which became unavailable or on short supply. But the new materials did not necessarily replace the older ones permanently nor make them obsolete. In many eases, they met an increased demand that could not be met by the natural product alone.

Today’s engineering resins and compounds serve in the most demanding environments. Their toughness, lightness, strength, and corrosion resistance have won many significant applications for these materials in transportation, industrial and consumer products. The engineering plastics are now challenging the domains traditionally held by metals: truly load-bearing, structural parts.

2.Find in the text English equivalents to the following words and word combinations:

органічні та неорганічні елементи, групи пластиків, промислове використання, потребувати, вимоги, з’єднувальний, дешевий, ненадійний, обмежений запас, заміщувати, застарілий, корозійна стійкість, виявляти, гума, споживчі товари.

3.Make sentences from the following words and translate them into Ukrainian:

1. Usually, is most, through, of, the application, done, and, pressure, forming.

2. Plastics, families, 40 different, are, there, over, of, in, today, commercial, use.

3. Different, dozens, variations, of plastics, have, of subtypes, families, and.

4.Which of the following are sentences and which are phrases?

1. Capable of being formed;

2. A successful design is a compromise;

3. To like to perform;

4. To keep up with development;

5. Compound serve in the most demanding environments;

6. Today’s engineering resins.

5.Answer the following questions:

1. How many families of plastics exist in commercial use?

2. What impression do most people have today concerning plastics?

3. What natural products were replaced by plastics?

4. What properties of engineering resins have won many applications?

Section 5

1.Read and translate the following text:

Date: 2015-01-02; view: 1989