Unit 7 nature of manufacturing plastics

GRAMMAR: Subjunctive Mood. Conditional Sentences.

1. A) Translate the following words, word combinations and chemical terms into Russian:

organic, polymers, resins, glycerol, rubber, compound, fatty acids, proteins, fibres, solution, cellulose, resistance, viscosimeter, starch, durability, substance.

b) Translate into Russian paying attention to the Subjunctive Mood and conditional sentences:

1. It is doubtful whether the observations of these scientists represent a new field of chemistry.

2. This procedure might be expected to support the claims of the Japanese scientists.

3. Magnetically induced changes as small as 0.04 pH unit would have been detectable by the method of measurements at constant flow rate.

4. Several theories have been proposed as to how mercury might go from inorganic form in water or a bottom sediment, into a methylated form of a fish.

5. We might expect that the activation energy necessary to start up a reaction would be equal to the energy needed to break the weakest chemical bond among the reactants.

6. If a substance conducts electricity, it will be heated.

7. If a metal were heated, it would be melt.

8. If a nonmetal had been cooled, it would have become brittle.

9. Provided the temperature were high, a metal would melt.

10. Had the temperature been raised, we should have got a new alloy.

11. If a chemical substance were heated, it might decompose.

2. Choose the correct forms:

1. If life (didn’t depend on, depended on) organic polymers, we (wouldn’t have, would have) food, clothing, shelter and transportation.

2. But for the complexity and fragility of the molecules of the natural organic polymers they (wouldn’t have defied, would have defied) the attempts to analyze their molecular structure until very recently.

3. There (would, will) be no industry of man-made organic polymers, (was, were) it not for modern methods of physical and chemical analyses.

4. It (would, will) be necessary to add that polymers have long-lived durability and resistance to high temperatures.

5. If the chemists (had not, did not) found out that many polymers have the form of long, flexible chains, they (wouldn’t, won’t) have been able to synthesize artificial polymers.

3. Read the text and translate it using a dictionary.

Text A

The age of polymers

Life depends fundamentally on organic polymers. If it were not so, we wouldn’t have food, clothing, shelter and transportation.

Indeed, nearly all the material needs of man could be supplied by natural organic products. The list of these materials and things made from them might be very long: wood, fur, leather, wool, cotton, silk, rubber, oils, paper, paint and so on. The organic polymers which these things are made from include: proteins, cellulose, starch, resins, and a few other classes of compounds.

There would be no industry of man-made organic polymers, were it not for modern methods of physical and chemical analyses which uncovered the principles that govern the properties of the natural polymers. One could list the principal products as fibres; synthetic rubbers, coatings, adhesives and a lot of materials called “plastics”. Plastics and synthetic coating are already in common use. It is desirable that they should be used on a large scale, and get further developed.

Synthetic polymers now available already possess several of the properties required in a structural material. They are light in weight, easily transported, easily repaired, highly resistant to corrosion and solvents, and satisfactorily resistant to moisture. It would be necessary to add that they have long-lived durability and resistance to high temperatures. A very important question could arise over whether synthetic polymers could be made inexpensive enough to compete with the structural materials such as metals and ceramics. The answer could be – “yes”.

It might seem odd that man came rather late to the investigation of organic polymers as the principal means of supporting life. The natural polymers such as proteins, cellulose and others dominated his existence and even in ancient times people used these materials.

Yet as late as the end of the 19th century polymer chemistry got little attention.

Chemists attacked sugar, glycerol, fatty acids and other ordinary organic compounds – dissolving, precipitating, crystallizing and distilling them to learn what these substances were composed of.

But only feeble efforts were made to investigate such common materials as wood, starch, wool, and silk. The substances composing these materials couldn’t be crystallized from solutions, nor could they be isolated by distillation.

It was only in the 20th century that the scientists began thorough investigation of these materials. Having used some powerful physical instruments, an electron microscope, viscosimeter, X-ray diffraction apparatus; they could have revealed the polymers in all their intricacy.

Their molecules were incredibly large, the molecular weights running as high as millions of unit, whereas simple organic substances such as, for instance sugar and gasolene have molecular weights in the range of only about 50-500.

The giant molecules can be composed of a large number of repeating units, they being given the name “ polymer ” from the Greek word poly (many) and meros (a part). Many polymers have the form of long, flexible chains. If the chemists had not found that out, they wouldn’t have been able to synthesize artificial polymers. This has led to the establishment of industries producing synthetic fibres and numerous polymeric materials, many of which were less expensive and superior in various ways to the natural materials.

4. Answer the questions:

1. What does the life depend on?

2. Why does life depend upon organic compounds?

3. What is the list of materials needed for life?

4. What do organic polymers include?

5. What have modern methods of physical and chemical analyses uncovered?

6. What products appeared on the basis of the discovery of polymers?

7. What properties do synthetic polymers possess?

8. Did people use natural polymers in ancient times?

9. What were those polymers?

10. When did the scientists begin thorough investigation of natural organic polymers?

11. What have they found out about polymers?

12. What are the molecules of polymers composed of?

5. Complete the following sentences using some active words and word combinations (see below ):

1. Life depends fundamentally on …

2. Nearly all materials needs of man could be supplied by …

3. One could list the principal products as fibres, synthetic rubbers, coatings, adhesives and a lot of materials called …

4. ... now available already possess several of the properties required in a structural material.

5. Synthetic polymers have long-lived … and … to high temperatures.

6. Having used some powerful physical instruments, …… , the scientists could have revealed the polymers in all their intricacy.

7. The name “polymer“ came from … poly (many) and meros (a part).

8. Many polymers have the form of …

plastics; durability; long, flexible chains; organic polymers; resistance; synthetic polymers; the Greek word; an electron microscope; viscosimeter; X-ray diffraction apparatus; natural organic products.

6. Retell the text using the scheme (see Un.1).

Text B

1. Match the English words and word combinations in A with their Russian equivalents in B.

A B

fibre	синтетические полимеры
synthetic polymers	смола
thermosetting plastics	волокно, нить
branch	молекула
chemicals	разветвленный
molecule	химические вещества
to synthesize	термореактивные пластмассы
resin	синтезировать
cellulose	клетчатка, целлюлоза
chain	цепь

2. Read the text trying to understand its main idea.