Read the text and answer the following questions.

1) What gives the rubber a more rigid structure?

2) What do synthetic rubbers fall into?

3) What process produces the SBR rubbers?

4) What are the stereospecific rubbers based on?

5) What properties have the EP rubbers?

6) What type of rubber has been developed in the USA?

7) What are the best known speciality rubbers?

8) What reactions are involved in the production of synthetic rubbers?

9) What are the polymerization reactions involved in the production of synthetic rubbers carried out in?

10) What is latex used for?

Translate into English.

1) Бутиловый каучук получают полимеризацией изобутилена, нитриловый каучук производится полимеризацией бутадиена и акрилонитрита. 2). Спрос на синтетический каучук продолжает увеличиваться. 3) В будущем синтетический каучук потребуется в еще большем количестве. 4) Строительство нефтехимических комплексов с производством синтетического каучука планируется в некоторых районах нашей страны.

Read the following text and put questions to the words in bold type.

Butadiene is produced by the catalytic dehydrogenation of n-butane or n-butylene. More recently it has been found possible to steam-crack hydrocarbon fractions in such a way as to produce large amounts of diolefins as well as olefins. This promises to become the cheapest process for the manufacture of butadiene.

Isoprene is produced by dehydrogenation of isoprene obtained by fractionation of straight-run pentane/isopentane.

Styrene is produced from ethylene and benzene.

The price of the base material, monomers, is an important feature in synthetic rubber manufacture. Ethylene and propylene are cheaply and abundantly available by cracking or steam-cracking petroleum fractions. Before World War II a process was developed for the manufacture of butadiene by first chlorination the C4 fraction (butane/butylene) of cracking gas to produce 2.3-dichlorobutane which was then converted into butadiene by dehydrochlorination.

Learn the following dialogue.

- The other day I’ve read about S. Lebedev who devoted all his life to the production of artificial rubbers.

- What material did Lebedev produce synthetic rubber of?

- It was produced of alcohol.

- Why didn’t he use petroleum hydrocarbons for that purpose?

- In those years petroleum refining techniques were low and very little raw materials could be obtained from petroleum.

- Now ethylene and propylene as raw materials for synthetic rubber are produced by cracking petroleum fractions.

10. Look through text A and say what it is about.

TEXT A

The general-purpose rubbers can be used for most purposes for which natural rubber was formerly the only product available. They are used either alone or in blends with other materials, particularly carbon black, for manufacturing cars and truck tyres, mouldings, extrusions, foot-wear, belting, wire and cable covers, flooring and the whole range of domestic articles. Where necessary they are vulcanized with sulphur or other vulcanizing agents.

The speciality rubbers have mostly been developed to achieve some particular property for specific applications for which general-purpose rubbers would not be technically suitable. They are generally more expensive and are limited in use to the applications for which they are most suited by their individual characteristics, such as resistance to high temperature, resistance to oil and solvents, and high flexural strength.

Butyl rubber is outstandingly impermeable to air and is accordingly widely used for inner tubes and curing bags. It alsohas good electrical properties and is used in wire and cable covers.

Nitric rubbers are extremely resistant to mineral oils, including aromatic oils, and are used for hoses, tubing and gaskets that come into contact with oil products.

Neорrene is resistant to mineral oils other than aromatics, it is also resistant to ozone and is therefore an excellent material for cable covers. Its non-inflammability is important for applications in the building industry.

Ethylene-propylene rubbers, EPR, are outstandingly resistant to ozone and to ageing, and are used for the manufacture of weather strips and window sealings in cars and buildings.

Hypalon rubber is highly resistant to heat and chemicals and, being white, lends itself well to the manufacture of light-coloured articles.

11. Give a title to the text.

12. Read paragraph 1 and answer the question. What are the general-purpose rubbers used for?

13. Read paragraph 2 and answer the question. What properties have the speciality rubbers?

14. Read the rest of the text and answer the questions.

1) What properties has butyl rubber?

2) What is it used for?

3) What properties have nitric rubbers?

4) What are they used for?

5) What is neoprene resistant to?

6) What is it used for?

7) What do you know about ethylene-propylene rubbers?

8) What can you say about hypalon rubber?

15. Say a few words about the uses of synthetic rubbers.

TEXT 4. POLYETHYLENE

Application. A process for the production of high density (0.959-0.968) polyethylene from 99% ethylene using а two-component catalyst system consisting of: (1) a titanium halide and (2) a cocatalyst based on a new class of aluminum hydride compounds:

Description. The catalyst from the preformation tank R₁ is suspended in an aliphatic solvent and then continuously fed to the reactor R₂, where is also sent a continuous flow of monomer. Both temperature and pressure are carefully controlled in order to retain polymer quality.

The polymer slurry, discharged from the reactor, is conveyed to a flash vessel (V₁) where the reaction is stopped and unreacted monomer and inerts are separated, and finally washed in V₂ with an extracting agent, which is recycled from the distillation unit, in order to remove catalyst residues.

The polymer, separated from the solvent and dried, is sent to a conventional blending and extrusion section.

Solvent and extraction agent from the separation and drying units are conveyed to the recovery plant where waxes are removed (V₃); finally in the C₁ column the recycle solvent is obtained as bottom, and the extraction agent as overhead.

Raw Material and Utility Consumption (Per metric ton of pelletized polyethylene):

Ethylene, 100%-Kg	1,090
Solvent, Kg
Low pressure steam, Kg	2.000
Electric power, Kwh
Cooling water, m^3
Fuel, Mkcal

 

Tasks on the text.