Match two parts of the following sentences:

1. Polythene is a plastic	a. outstanding resistance to water, alcohols, and concentrated acids and alkalis.
2. Epoxy resins have outstanding	b. very low density, reasonable strength and toughness but low stiffness
3. Polystyrene is a thermoplastic	c. a firmer bond.
4. PVC is a colourless solid with	d. adhesion, toughness and resistance to attack from chemicals
5. This new glue makes	e. made from ethane.
6. Polythene is a white waxy solid with	f. covered with a plastic coating
7. Add water, mix it into a paste, and	g. produced by the polymerization of styrene.
8. Electric wires are usually	h. fill the cracks with it.

 

14. Comprehension check. Answer the following questions:

1. What types of plastics do you know?

2. What are the features of the epoxy resin?

3. What is epoxy resin used for?

4. What is PVC usually used for?

5. What are the typical applications of polystyrene?

6. When was polyethylen synthesized?

7. Under what conditions is polyethylen synthesized?

8. What sorts of polyethylen can be synthesized?

You are given the definitions from target vocabulary (ex.11). Guess the words:

a) an apparatus that collects and stores electricity;

b) a state of being stuck together;

c) a small bit like a fine grain;

d) a covering on or over a surface;

e) a whitish mass of very small bubles on the surface of a liquid;

f) soft sticky mixture of powder and liquid that is easily shaped or spread

16. Translate into English using the target vocabulary:

1. Эпоксидная смола затвердевает когда смешивается с отвердителем и пластификатором.

2. Эпоксидные смолы используются в качестве клея, а с добавками — в строительстве лодок и спортивного снаряжения.

3. ПВХ — бесцветное твердое вещество с выдающейся устойчивостью к воздействию воды, спиртов, концентрированных кислот и щелочей.

4. ПВХ широко используется при производстве изоляции для проводов.

5. Выдувка непластифицированного ПВХ используется при производстве прозрачных бутылок для напитков.

6. Полистирол легко вспенивается и используется для упаковки.

7. Полиэтилен — воскообразное вещество белого цвета с очень низкой плотностью и малой жесткостью.

 

Speaking. Tell your groupmates about some of the chemical additives used in plastics to produce desired characteristic.

18. You are going to read Text C. Study the vocabulary from the text:

1. anisotropic	a. анизотропный
2. ceramic	b. керамический
3. expansion	c. расширение
4. fiber	d. волокно, нить
5. fibreglass	e. стекловолокно
6. matrix	f. матрица
7. reinforced	g. упрочненный
8. specific stiffness	h. удельная жесткость
9. specific strength	i. удельная прочность

Read Text C and say what «composite materials» are.

Text C. Composite materials

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

 

20. Study Text C and find the adequate English equivalents of the following words and phrases:

Композитные материалы, уникальные механические качества, керамический, полимерные матричные композиты, иметь некоторые недостатки, составлять 60% объема, углепластик, привлекательные качества; структура, подвергающаяся воздействию разнонаправленных сил, волокна параллельны, прочные связи, инженер-конструктор, свойства

 

21. Comprehension check. Answer the following questions:

1. What are the best properties of fibre-glass?

2. What do composite materials usually consist of?

3. What is used as a matrix in composites?

4. What is used as a filler or a fiber in composites?

5. How are the composite materials with ceramic and metal matrices called?

6. What are the advantages of composites?

7. What are the disadvantages of composites?

8. Why anisotropic properties of composites should be taken into account?

22. Translate into Russian:

1. PMC is fabricated so that all the fibres are lined up parallel to one another. 2. Forming strong connections between separate composite material components is difficult. 3. Fabricating composite materials is a complex process. 4. Composite materials have certain advantages over conventional materials. 5. Nowadays, composites are being used for structures such as bridges, boat-building etc. 6. Continuous-fibre composites are generally required for structural applications.

 

23. Fill in the correct word from the list:

Foams, an extruder, a polymer, composites, fibre, chains, plasticizers, bonds, manufacturing, additives, raw materials.

1. The first stage in ______ plastic is polymerization. 2. Chemical ______ are often used in plastics to produce some desired characteristic. 3. These oil-based ______ are relatively widely available and inexpensive. 4. ________ make a polymer more flexible, lubricants reduce problems with friction, and pigments add colour. 5. Many plastics are manufactured as _______. 6. Plastic _______ are composites of plastic. 7. _______ is a device that pumps a plastic through a desired die or shape. 8. Silicon does not form double _______ or long silicon _______. 9. Antioxidants protect ______ from chemical degradation by oxygen or ozone; similarly, ultraviolet stabilizers protect against weathering. 10. Polypropene is also often used in housewares and as _____ for carpeting and rope.

24. Read Text D and choose a title for each paragraph:

a. Additives

b. Raw Materials.

c. Shaping and Finishing.

d. Use.

e. Synthesizing the Polymer.