VI. Oral Practice.

Exercise 20. Ask your friends:

1. for what different species are grown;

2. what leaves both fiber and seed flaxes have;

3. how the flowers of most cultivated varieties range in colour;

4. why the straw is retted;

5. why the straw is spread on the ground;

6. why the retted stems are crushed and broken;

7. in what manufacture flax fibers are used;

8. where flax fiber is produced.

Exercise 21. Basing your answers on information from Text B:

a) give the characteristic features of flax plants;

b) name the main spheres of using both fiber and seed flaxes.

Exercise 22. Prove that the use of flax fiber for cloth originated thousands years ago.

VII. Reading and Comprehension.

Exercise 23. Read Text C without a dictionary.

Text C.

New Economical Technology for Cottonized Flax Fiber Preparation

Cottonized flax fibre requires new technologies for preparation of it. Ukrainian Institute of Textile Production (Kyiv) has developed new technology for boiling and bleaching of cottonized flax fibre. Such a technology is very economical and enables to get flax fibre of quality that meets modern requirements of chemical and ecological safety. They use new kind of chemical and new processing techniques for preparation of cottonized flax fibre. The technology has been succesfully tested on works floor. About 14% of world volume flax fibre is produced within Ukraine. More than a half of that flax fibre is a short one. Existed technologies of short flax fibre processing allow to make the products that are limited requested.

For last three years Ukrainian Research Institute of Textile Production (URITP) developed nontraditional technologies for short flax fibre use. Technology for short flax fibre cottonization and technology for treatment of it allow to extend the field of short flax fibre use and develop new kind of products.

Treatment of cottonized fibre is carried out by two ways.

First Method.

Superposed method of treatment consists of simultaneous boiling and bleaching by means of secure (IV class of safety) ecologically clean silicon-organic chemical that is dissolved in water.

Essential difference of the chemical is its ability of complex acting (simultaneously as wetting and dispergating agent and as stabilizer of hydrogen peroxide decomposition) directly on raw cillulic fibre and admixtures on the surface of it and into the fibre as well. In the case it takes less time for boiling and bleaching process. The ability of the chemical to dispergate and extract natural admixtures (lignin, wax, etc.) provides good quality of fibre preparation.

Content of chemical: silicon-organic chemical; hydrogen peroxide (100%); water.

Quality of fibre preparation is evaluated by following parameters: absorption, whiteness, impurity, linear density, length, breaking load, time of steeping.

Parameters of flax fibre processed with the first method.

№	Parameters	Normal	After treatment
1. 2. 3. 4. 5. 6.	Absorption, gr./gr. Whiteness, % Impurity, % Length, mm. Time of steeping, sec. Breaking load, gr./tex.	26 85 0.15 20-40 0-3 30	35 88.1 0.05 39-40 3 39

Silicon-organic chemical is decomposited biologically (more then 90% of it) so the technology of flax fibre preparation by means of it is ecologically clean and more effective because of less quantity of scouring. Advantage of the chemical is its universality, it can be used for any kind of celluloic fibre.