Abrasive, insulating, translucent, available, origin, source, valuable, by-products

1. What raw materials are … for the production of plastics?

2. Rubbers are widely used due to their … properties.

3. Oil … can be used to produce plastics.

4. Plastics can be of inorganic …

5. Diamond is a natural … material.

6. Fluoroplastics are good electrical … materials.

7. Gum resins are the … materials for natural rubbers.

8. Organic glass is a … material.

1. Agree or disagree with the following statements. Prove your reason. Use the expressions: Exactly so…, On the contrary….

1. Plastics are nonmetals.

2. Plastics consist of only polymers.

3. Different plastics do not have any common qualities.

4. Plastics are produced of raw materials which are very rare.

5. Plastic materials have a lot of useful properties.

6. Some abrasive materials are artificial.

7. Some plastics can be used to produce machine-elements.

8. Plastics find different application depending on their properties.

Translate the following text in writing. Use a dictionary. Find the facts that explain why plastics have replaced metals in some applications.

Plastics

Plastic materials are not found as such in nature. They have many advantages over such materials as metals, glass and wood. One of them is lightness. A given volume of polythene weighs less than one-eighth of an equal volume of iron and less then half of the same volume of aluminum.

While some types of plastics are very tough, e.g., nylon, and others may be relatively brittle, as, say, polystyrene, they are, with few exceptions, not as strong as iron or steel or concrete when it comes to supporting great weights.

Plastics do not rust and therefore require no protective layer, such as paint, which can subsequently peel off. They can, of course, be coloured and such colour is part of the material. It cannot come away or be chipped off. Plastics do not like heat. Some types will withstand higher temperatures than others and the ceiling temperature is constantly being raised as new varieties appear.

Plastics have found wide application both in everyday life and in industry. We can hardly name a branch of industry where plastics are not applied. The insulation and dielectric properties of plastics led to their early use in the electrical engineering industry, which was followed by special application in mechanical engineering. Plastics used as materi­als of construction in the form of sheets, rods or tubes are replacing the conventional metals. Automibile, aircraft and shipbuilding industries have also made use of advantages of­fered by plastics. Today all plastic gears for ma­chinery are made from fabric-base laminates. Gears made from lam­inated phenolic materials are much more resilient than similar steel gears; indeed the degree of resiliency is claimed to be as much as forty times that of steel.