Text В: «TYPES OF PLASTICS»




Epoxy resin.

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 outstandingadhesion, toughness, and resistance to attack from chemicals. They form strongbonds and have excellent electricalinsulationproperties. 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.

2. PVC (polyvinyl chloride)

PVC (polyvinyl chloride) is a thermoplastic polymer made from vinyl chloride is a col­ourlesssolid with outstanding resistance to water, alcohols, and concentratedacids andalkalis. It is obtain­able as granules, solutions, lattices, andpastes. When compounded with plasticizers, ityields a flexible mate­rial moredurable thanrubber. It is widely used for ca­ble and wireinsulation, in chemical plants, and in the manufacture of protectivegarments. 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.

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 lightfixtures, toys, bottles,lenses, capacitordielectrics, medicalsyringes, andlight-duty industrial components. Extruded sheets of polystyrene are widely used for packaging,envelope windows, and photographic film. Its resistance toimpact can beimproved by the addition of rubbermodifiers. Polystyrene can bereadily foamed; the resulting foamed polystyrene is usedexten­sively for packaging.

4. Polythene (polyethene, polyethylene)

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 bar at 200°C. This produced low-density poly­thene (LDPE). A relatively high-density form (HDPE) was synthesized in the 1950s using a complexcatalyst. Poly­thene is a whitewaxy 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.

Vocabulary:


adhesion— прилипание

adhesive — клей

bond — связи, узы

insulation — изоляция

casting — литье

void — пустота

solid — твердое тело, твердый

acid — кислота

alkali — щелочь

to obtain — доставать, получать

granule— гранула

solution — раствор

lattices — латексы

paste— паста

yield— выход

durable — прочный

rubber— резина, каучук

garment — предметы одежды

lens —линза

capacitor — эл. конденсатор

syringe— шприц

light-duty — неответственный

envelope — зд. обрамление

impact — удар

improved — улучшенный

modifiers — модификаторы

addition — добавление

readily — легко, с готовностью

foam — пена

catalyst — катализатор

wax — воск

reasonable — приемлемый, неплохой

coating — слой, покрытие


General understanding:

1. What are the types of plastics?

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?

Exercise 5.3. Translate into Russian:

1. Polythene is a plastic made from ethane.

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

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

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

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

Exercise 5.4. Translate into English:

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.





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