Answer the following questions:

1. What task is considered as an important task for all dyers?

2. What are requirements of successful stripping?

3. What can you say about "back stripping" and destructive stripping?

4. What is the necessary condition of nback stripping'1?

5. In what medium are anthaquinon dyes best attached?

6. What role does the temperature play in removing colour?

7. When ie it required to repeat the process?

8. When are both level and milling dyes used?

9. What characteristics of Dianyl and Iguafen SS can you name?

10. 10.What is Iguafen A?

Вариант IV

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Natural and synthetic rubber

I. Apparently rubber was first discovered by natives in Central andSouth America. They used it as waterproofing material. Samples of this material were carried back to Europe by early explorers: it was soon found that small pieces of the elastic substance were handy for erasing pencil marks and thus it was given the name"rubber" .

2. Although rubber can be found in the milky fluid of certain plants, its chief source is the latex obtained from the rubber tree.

3. Natural rubber is a thermoplastic material that becomes soft and sticky when heated and hard when cooled. Prior to 1839,these roperties were responsible for many disappointing results in the manufacture of raincoats and other waterproof textiles. In experi­ments designed to improve the properties of rubber, Charles Coodyear, in 1839, accidently spilled a mixture of rubber and sulfur on a hot stove and discovered the process he later called vulcani­sation. Chemically, vulcanization involves a reaction of sulfur with the double bonds of the rubber molecules producing cross linkages of sulfur between adjacent chains of hydrocarbons. A soft

rubber is produced when the sulfur content is kept around 2 per cent, while extensive cross-linking, which occurs when around 30 cent of sulfur is used, resulte in hard rubber.

5. The modern rubber industry has developed many special types of rubber for various purposes and has improved the quality by conious research. More recent research by the rubber industry in­volves vulcanization by radiation with gamma rays. Not only many ler articles, but also full-sized automobile tire have been riized without the uae of heat or curing agents .

6. As isoprene was referred to natural rubber several chemistsed the polimerization of isoprene. It was that sodium cata-d the polymerization of the compounds and products with properties similar to rubber could be synthesized. The two main drawbacks to industrial development of synthetic rubbers were the high cost of synthetic rubber and the inferior quality of the synthetic product. One of the first synthetic polymers to compete with natural rubber was Neoprene, it possessed properties that made it lesirable than rubber for certain purposes.

6. Neoprene is a polymer of chloroprene which is synthesized from acetylene. The most outstanding property of Neoprene is its resis­ tance to heat, light, oils and chemicals. Аs the cost of Neoprene is about twice that for natural rubber, it is used wherever resis­ tance to oxidation and chemicals is important.

7. Several types of synthetic polymers were investigated with a view toward mass production to supply the large quantities of rub­ber needed. At present, a synthetic rubber composed of 80 per cent butadiene and 20 per cent styrene is used extensively in the ma­ nufacture of tires and rubber goods. An other co-polymer of buta­ diene and acrylonitrile is developed. This type of synthetic rub­ ber is not .satisfactory for tires but its resistance to the solvent action of gasoline and oil finds many industrial applications.

1. handy for erasing pencil marks - удобный для стирания каран­даша

2. cross linkage - поперечные связи

3. curing agents - вулканизирующие вещества

Answer the following questions:

1. Where was rubber first discovered?

2. Why did it get the name "rubber"?

3. What are the properties of the natural rubber?

4. What does vulcanization involve?

5. What is more recent research of the rubber industry?

6. What is the polimerization of isoprene?

7. What was the first synthetic polymer developed?

8. What are the main properties of Neoprene?

9. What kind of synthetic rubber is used in the manufacture of tires?

10. What is the cost of Neoprene?

Вариант V

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Plastics

1. Viewed from the standpoint of organic chemistry it may be said that we are living in a "plastic age". So many articles formerly constructed of metal, wood, rubber, leather, or ceramics have been replaced by plastics. The use of plastic material in toys, swim­ming pools, home construction, automobiles, boats, airplanes and urticles of clothing has increased tremendously in the past few fears. The superior properties of many plastics have resulted in Ihe increased application of plastics in the electrical, radio, television, furniture, petroleum and food industries.

2 . Plastics are synthetic or natural materials which contain as an ential ingredient an organic substance of high molecule weight. They are solid in their finished state, but at some stages during manufacture or processing into finished articles they can be molded . Organic substances of high molecular weight are synthesized from relatively simple chemical components by condensation and polymerization reactions with synthetic resins. They are also pro­duced by chemical treatments of natural substances of high molecular weight, such as natural reaina, proteins and cellulose.

3 The modern plastic industry deals with moldable materials manu­red from organic compounds. A convenient classification of latics can be made on the basis of their behavior toward heat. Thermoplastics are permanently fusable, they melt or soften when ed and they harden when cooled. Thermoplastics are composed Line of molecules that is their atoms are joined in long chain-itructure with few cross linkage. Molecules of this type uaually swell or are soluble in some organic solvents.

4.Plastics are sometimes used without the addition of plaaticizers or fillers for the fabrication of commercial products, the being polyethilene film . However, they are usually modified by addition of fillers, dyes and pigments to give them the desired properties for specific uses and for processing.

5.Plasticis are synthetic polymers produced in the laboratory by ad reactions of various monomers. From a chemical standpoints polymers are divided into two main types, addition ро1уmers lonaation polymers.

6. Addition polymers are produced by the combination of monomers ■ double bond. Examples of such polymers are rubber, various synthetic rubbers and the vinyl type polymers. Co-polymerisation also produced a type of addition polymer by the combination of two or more different monomers.

7. Condengation polymers are formed by a chemical reaction bet­ween monomers that contain at least two reactive groups. The mono­mer units can thus react with other units to produce an unbroken chain of high molecular weight. Examples of condensation polymers are cellulose, nylon and the phenolformaldehyde type of plastics.

1. Viewed from the standpoint of - рассматривая с точки зренкя

2. mold - отливать форму

3. plasticizers or fillers - пластификаторы или наполнители

4. polyethilene film - полиэтиленовая пленка

Answer the following questions:

1. Where do we use plastics?

1. What does plastic аз essential ingredient contain?

2. How are organic substances produced?

3. What is a convenient classification of plastics?

4. What are thermoplastics composed of?

5. What process are synthetic polymers produced by in the laboratory?

7. What types are polymers divided into?

8. What examples of addition polymers do you know?

9. What are condensation polymers formed by?

10. What condensation polymers do you know?

Контрольное задание * 4

для студентов специальности "Проектирование и технология трикотажных изделий"

Вариант I

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Spinning

I. Before fibres or filaments can be used in the making of cloth they must be converted into yarns. The process is called spinning.

2. Spinning is really a twisting of the fibres round each other so that they hold together and form a strong compact yarn. Not only the natural fibres, but also the chemical ones are to undergo a number of operations as they require to be doubled (i.e. several filaments have to be joined together) and twisted to give a strong yarn of suitable thickness for the fabric into which they are to be made.

The three necessary steps in spinning are: drawing out or "attenuating" the fibres, twisting them and winding the finished /urn on a bobbin.

3. The term "yarn" is applied to a twisted strand of fibres that in used in making woven or knitted cloth. It may consist of a single strand or of two or more strands twisted together.

4. Yarn should not be confused with thread. Thread is made by combining several yarns and twisting them together into one. Besides,the thread is given a smooth finish. Thread is usually stronger, smoother, and more uniform in diameter than yarn. Thread is used for sewing both at home and in clothing and footwear trades, yarn being used in the construction of fabrics either by weaving or by knitting.

5.A considerable amount of preparation is necessary before a yarn can be done from raw materials.

6. In their raw state the natural fibres are quite unsuitable for immediate conversion into yarn and they can be spun only after a number of preparatory operations. Cotton when it is picked still is seeds adhering to the fibres, flax is found as the inner bark of the stem of the flax plant, wool as a matted greasy mass of crimpy hairs, and they all contain impurities. These impurities should be removed, the fibres should be thoroughly cleaned plnced in a somewhat parallel position before spinning can take place.

7.As to silk, it has to be wound off the hardened cocoon, and boiled off to become a silk filament.

8.The only fibres which in their raw state are practically ready for the weaver's loom are the chemical fibres, which are made in a continuous filament or thread. Even these are frequently cut into short staples of equal length and spun in a similsr fashion to the natural fibres.

9.Nobody can say where and when spinning originated. The basic principles of drawing and spinning - draft and twist - were known many thousands of years ago. Spinning began with the invention of the spindle and was a very important part of women's work.

10. Spinning seems to be the one occupation which has belonged to women all through the ages. Girls learned to spin so early that they hardly remembered when they did not know how.

11. The word " spinster" formerly meant "a maiden who spins" and even to this day it means both "an old maid" and "an unmarried woman". In the 16 th century the spindle and the distaff were re­ placed by the spinning wheel. Machine spinning may be said to have started only in the 18 th century with the introduction of the Spinning Jenny.