Век химии (Английский язык для студентов химического профиля). Учебное пособие

2. Read the text and be ready to say if the following statements are true or false. Use the following phrases:

I think it’s right.

It seems to be wrong.

I can’t agree with it.

As far as I know …

To my mind

On the contrary

1.Polythene is a plastic made from vinyl chloride.

2.Epoxy resins have outstanding adhesion, toughness and resistance to attack from chemical.

3.PVC is a colorless solution with outstanding resistance to water, alcohols, and concentrated acids and alkalis.

4.Polystyrene is a thermoplastic produced by the polymerization of ethane.

5.Polythene is a white waxy solid with very low density, reasonable strength and toughness but low stiffness.

TYPES OF PLASTICS

Epoxy resin is a thermoset plastic containing epoxy groups. Epoxy resin hardens when it is mixed with solidifier and plasticizer. Plasticizers make a polymer more flexible.

Epoxy resins have outstanding adhesion, toughness, and resistance to attack from chemicals. They form strong bonds and have excellent electrical insulation properties. Large, complex, void-free castings can be made from them. They are also used as adhesives, and in composites for boat building and sports equipment.

PVC (polyvinyl chloride) is a thermoplastic polymer made from vinyl chloride is a colourless solid with outstanding resistance to water, alcohols, and concentrated acids and alkalis. It is obtainable as granules, solutions, lattices, and pastes. When compounded with plasticizers, it yields a flexible material more durable than rubber. It is widely used for cable and wire insulation, in chemical plants, and in

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the manufacture of protective garments. Blow moulding of unplasticized PVC produces clear, tough bottles which do not affect the flavour of their contents. PVC is also used for production of tubes or pipes.

Polystyrene is a thermoplastic produced by the polymerization of styrene. The electrical insulating properties of polystyrene are outstandingly good and it is relatively unaffected by water. Typical applications include light fixtures, toys, bottles, lenses, capacitor dielectrics, medical syringes, and light-duty industrial components. Extruded sheets of polystyrene are widely used for packaging, envelope windows, and photographic film. Its resistance to impact can be improved by the addition of rubber modifiers. Polystyrene can be readily foamed; the resulting foamed polystyrene is used extensively for packaging.

Polythene (polyethene, polyethylene) is a plastic made from ethane. It is one of the most widely used important thermoplastic polymers. It was first developed by the polymerization of ethane at a pressure of 2,000 bars at 200 ºC. This produced low-density polythene (LDPE). A relatively high-density form (HDPE) was synthesized in the 1950s using a complex catalyst. Polythene is a white waxy solid with very low density, reasonable strength and toughness, but low stiffness. It is easily moulded and has a wide range of uses in containers, packaging, pipes, coatings, and insulation.

3.Make up the plan of the text.

4.Give a brief summary of the text.

Text D

1. Read the text and choose the most suitable title out of the given once:

a)Advanced Composites.

b)Composit Materials.

c)Composites.

The combinations of two or more different materials are called composite materials. They usually have unique mechanical and

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physical properties because they combine the best properties of different materials. For example, a fibre-glass reinforced plastic combines the high strength of thin glass fibres with the ductility and chemical resistance of plastic. Nowadays composites are being used for structures such as bridges, boat-building etc.

Composite materials usually consist of synthetic fibres within a matrix, a material that surrounds and is tightly bound to the fibres. The most widely used type of composite material is polymer matrix composites (PMCs). PMCs consist of fibres made of a ceramic material such as carbon or glass embedded in a plastic matrix. Usually the fibres make up about 60 per cent by volume. Composites with metal matrices or ceramic matrices are called metal matrix composites (MMCs) and ceramic matrix composites (CMCs), respectively.

Continuous-fibre composites are generally required for structural applications. The specific strength (strength-to-density ratio) and specific stiffness (elastic modulus-to-density ratio) of continuous carbon fibre PMCs, for example, can be better than metal al1oys have. Composites can also have other attractive properties, such as high thermal or electrical conductivity and a low coefficient of thermal expansion.

Although composite materials have certain advantages over conventional materials, composites also have some disadvantages. For example, PMCs and other composite materials tend to be highly anisotropic — that is, their strength, stiffness, and other engineering properties are different depending on the orientation of the composite material. For example, if a PMC is fabricated so that all the fibres are lined up parallel to one another, then the PMC will be very stiff in the direction parallel to the fibres, but not stiff in the perpendicular direction. The designer who uses composite materials in structures subjected to multidirectional forces, must take these anisotropic properties into account. Also, forming strong connections between separate composite material components is difficult.

The advanced composites have high manufacturing costs. Fabricating composite materials is a complex process. However, new manufacturing techniques are developed. It will become possible to produce composite materials at higher volumes and at a lower cost than is now possible, accelerating the wider exploitation of these materials.

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2. Write out:

a)key worlds and terms;

b)the sentences expressing the main idea of each paragraph.

Unit 8

GRAMMAR. Modal Verbs

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

butadiene, dimensional, flexural, opaque, polystyrene, rigidity, subsequent, toughness, unique, versatile, based on the first letters, with essentially no loss, sediment, substitute, residue

b) Translate the following derivatives into Russian:

1. develop, development; 2. compose, composition; 3. monomer, monomeric; 4. adopt, adoptation; 5. polymer, copolymer, polymerization, polymerize; 6. nature, natural; 7. improve, improvement; 8. tough, toughness; 9. introduce, introduction; 10. rigid, rigidity; 11. resist, resistant, resistance; 12. apply, application; 13. viscous, viscosity; 14. use, useful, useless;

15.process, processing.

c)Translate into Russian paying attention to the Modal Verbs:

1.Plastics can do a better job, often at lower cost.

2.The development of lamination has shown how modern plastics may be used for many engineering and structural applications.

3.We are able to build car bodies and the hulls of the boats from plastics.

4.We shall have to seek new sources of organic chemical materials.

5.The present century is the time when one has to understand how to make all the new synthetic materials from simple chemicals.

6.We can make alcohol by fermentation of the sugars produced by fast-growing plants.

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7.One has to keep in mind that the most striking property of the white phosphorus is its activity with oxygen.

8.They have to determine this substance.

9.Adhesion should not be confused with friction.

10. Coal and petroleum are capital assets; the world has a limited supply, and we cannot replace the material we use.

2.Put the words in the correct order to form sentences.

1.can be, remelted, and, with, essentially, no, in, properties, ABS plastics, various, loss, reformed, into, shapes.

2.have ousted, plastics, they, do, job, often, at lower cost, materials, can, a better, older, because.

3.plastics, may, be, for, many, and, structural, modern, used, engineering, applications.

4.we, make, by, the, sugars, produced by, fast-growing, plants, can, alcohol, of, fermentation.

5.are, build, car, and, the hulls, the, boats, of, plastics, able to, bodies, from, we.

Text A

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

ABS PLASTICS

A unique family of plastics has evolved and developed during the last twenty years. These plastics are composed of three monomeric chemicals – acrylonitrile, butadiene and styrene. The name ABS, based on the first letters of each of the monomeric components has been adopted for this family. ABS plastics are composed of styrene acrylonitrile copolymer as the continuous phase and a dispersed phase of butadiene-acrylonitrile rubber or a butadiene containing rubber onto which styrene-acrylonitrile monomers are grafted.

Various combinations of properties are possible, thus making these polymers most attractive for a larger number of current and newly developed applications.

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ABS polymers are true thermoplastics similar to polystyrene, polyvinyl chloride, polyolefins, nylon, etc. On application of heat they are softened, and when pressure is applied they attain viscous flow.

Upon cooling they harden and on reheating are resoftened. Thus they can be remelted and reformed into various shapes with essentially no loss in properties. As a result, ABS plastics are extremely useful and versatile, since ease of processing and forming allows them to be used for a great number of applications. In their natural form ABS plastics are opaque, similar in this respect to the impact polystyrenes.

General Properties of ABS Plastics

The excellent combination of properties which ABS plastics offer has spurred the growth of these plastics into many applications. No one single property, but rather the combination of properties of ABS plastics has made them outstanding. Some of the properties, which make these plastics extremely useful, are:

1.Moderate price.

2.Ease of fabrication.

3.Good combination of toughness, rigidity and mechanical properties.

4.Wide colorability.

5.Good dimensional stability.

6.Nontoxicity.

7.Good water resistance.

8.Excellent chemical resistance.

The strength of a fabricated item produced from an ABS plastic is dependent on a number of variables, namely, the fabrication conditions used, the design and shape of the finished piece, the method of stress application, and the environmental conditions encountered. It should be stressed that the conditions under which the plastic part is formed play a very important role on the subsequent mechanical properties of ABS plastics. This is true to all thermoplastics. When ABS polymers are heated and subjected to fabricating conditions, such as injection molding, sheet or profile or pipe extrusion, or thermoforming, many of the long chain polymer molecules change their position and shape and become more aligned:

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in other words, they become oriented or stretched out pointing in the direction of flow. Thus, most properties of ABS plastics are not only time and temperature-dependent but are also frequently directiondependent (anisotropic). Therefore, in describing the properties of ABS plastics, it is important, if at all possible, to specify the properties in relation to the flow direction and the degree of orientation.

4. Answer the questions.

1.What is a unique family of plastics composed of?

2.What is the name ABS based on?

3.How is significant improvement in toughness over polystyrene attained?

4.What other properties of plastics do you know?

5.What are ABS polymers similar to?

6.What happens to ABS polymers upon cooling and heating?

7.Why are ABS plastics extremely useful?

8.What plays a very important role on the mechanical properties of ABS plastics?

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

1.The name ABS, based on the first letters of each of the monomeric components has been adopted for …

2.By introducing acrylonitrile monomer into a similar system, a significant improvement in all these properties is obtained, as well as outstanding … and … .

3.Various combinations of properties are possible, thus making these polymers most attractive for a larger number of current and newly developed … .

4.ABS plastics are extremely ... and … , since ease of processing and forming allows them to be used for a great number of applications.

5.The … of a fabricated item produced from ABS plastic is dependent on a number of variables.

6.Most properties of ABS plastics are not only time and temperature-dependent but are also frequently … .

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strength; this family; versatile; resistance; applications; toughness; useful; direction-dependent (anisotropic).

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.

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

PLASTICS IN THE CHEMICAL AGE

The plastics industry is typical of the industries that have developed in recent years as a result of chemical research. The chemist is a key man in the plastics industry, and it is from chemical laboratories that new plastics are appearing almost day by day.

Little more than twenty years ago, p1astics were still widely regarded as cheap substitutes for traditional materials such as wood and porcelain. Today plastics have established themselves as wonderful new materials in their own right. They have ousted older materials because they can do a better job, often at lower cost.

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We find new plastics encroaching in the fields where metals have reigned supreme. The development of new techniques, such as lamination, has shown how modern p1asties may be used for many engineering and structural applications. We can make gears and bearings for heavy machinery from laminated plastics. We can build car bodies, and the hulls of boats; we can pump our water supplier through plastic pipes, and support large buildings on plastic beams.

In time we shall have seagoing ships with plastics used for almost everything from the crockery on the tables to the hull itself. We shall fly at supersonic speeds in plastic aircraft, and motor in cars with plastic bodies. Houses and public buildings will be constructed from plastics panels supported by plastic beams. We shall find plastic spaceships carrying us to the moon.

As the demand for plastics grows, the need for chemical raw materials will increase. Plastics are largely organic chemicals, in which the “backbone” of the molecule consists of carbon atoms. They are made from simpler organic chemicals in which the molecules contain fewer carbon atoms, which are manipulated by the plastics chemist into thread-like structures.

Today, we draw our supplies of simple organic chemicals very largely from coal and petroleum. These are the chemical residues of plants and animals that lived millions of years ago, and they contain a variety of different organic substances. We obtain simple chemical raw materials from coal by heating it in retorts, and from petroleum by refining and processing techniques. Coal and petroleum are capital assets; the world has a limited supply, and we cannot replace the material we use. As the demand for organic chemicals increases, the stocks of coal and petroleum will diminish; and some day, they will be gone.

Before this happens, we shall have to seek new sources of organic chemical raw materials, and we shall find them in the carbon dioxide of the air. This is the gas from which the growing plant builds up the sugar and other substances as organic raw materials, without waiting for nature to turn them into coal and oil.

It seems likely that alcohol will become the most important chemical raw material of all as supplies of coal and petroleum dwindle. We can make alcohol by fermentation of the sugars produced

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by fast-growing plants, and it will provide us with the raw materials for plastics and other synthetic chemical industries. The tropical countries of the world will use their vast areas of land for the cultivation of sugar-producing crops.

It is probable, too, that we shall in time discover the secrets of photosynthesis, by which the plant uses sunshine to convert carbon dioxide into sugars and we shall use some synthetic process of this sort to turn carbon dioxide from the air into simple organic chemicals without depending entirely upon the growing plant to do it for us.

This century is the time when man began to understand how to make all the new synthetic materials from simple chemicals; materials, such as fibres and rubbers, synthetic drugs and dyes, insecticides and weed killers, hormones and vitamins — and, of course plastics.

3.Divide the text into some logical parts and entitle them.

4.Translate the following sentences into English using lexical material of the text.

1.Разработка слоистых пластмасс показала, что они могут использоваться для многих технических и строительных целей.

2.Мы можем строить автомобили и каркасы лодок из пластмасс.

3.Полагают, что в недалеком будущем мы сможем строить самолеты из пластмасс.

4.В настоящее время, как известно, сырьем для получения пластмасс являются простые органические химические вещества из угля и нефти.

5.Так как мы имеем ограниченные запасы угля и нефти, то

углекислый газ.

6. Возможно, что спирт станет одним из самых важных видов химического сырья.

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