Processing of Flax

Notes:

1) … have to be selectively hydrolyzed – мають бути відбірково гідролізовані

2) unless treated before … - якщо не буде оброблена перед …

3) the possibility of reusing … - можливість використати ще раз

Flax fibre has a complex morphological structure. It is characterized by bundles of cellulosic fibrils. They are cross-linked by pectin, hemicellulose and lignin. These elements have to be selectively hydrolyzed or removed during retting, chemical processing, spinning and finishing. After mechanical processing of the fibre rove bobbins are treated with caustic boil. Peroxide and chlorite treatments are used to remove the unwanted non-cellulosic polysaccharides and sprit. The energy cost required for heating process water to 98°C is very high. Together with peroxide and chlorite treatment it is the most expensive component of processing flax. The water consumption including post-treatment rinsing amounts to approximately 100 litres per kg. of fibre. This water can also cause pollution unless treated before releasing into waterways.

The reduction of highly toxic chlorinated organic by-products is also a problem in textile processing. An alternative to NaCO₂ needs to be found. Bleaching rove bobbins using H₂O₂ alone is not well suited for rove processing. The reason for this is the presence of sprit. Sprit is a lignified-residual plant material, especially in low quality raw material.

These are two possible alternatives to chlorite treatment: a) enzyme treatment;

b) chemical treatment.

It has been known for some time that the caustic boil can be replaced by a suitable combination of enzymes. They are commercially available. Sprit and residual non-cellulosic polysaccharides can be braked down with lignin degrading enzymes.

The benefits of using an enzymes process at 30°C to hydrolyze pectin, hemicellulose and lignin are quite clear. Damage to cellulose fibrils are minimized or eliminated. It results in higher yarn quality. These two factors and the possibility of reusing the process liquor enhance the environmental and economic considerations of the enzyme treatment process.

III. Language.

Exercise 9. Match the words and word-combinations in column A those in column B.

A	B
1. non-cellulosic 2. unwanted 3. sequence 4. peroxide treatment 5. energy cost 6. water consumption 7. pollution 8. enzyme treatment 9. residual 10. waterways	1. нецелюлозний 2. обробка перекисом 3. енергетична вартість 4. споживання води 5. непотрібний 6. послідовність 7. залишковий 8. водні шляхи 9. обробка ензимом 10. забрудненя

Exercise 10. Fill in the blanks using words in brackets.

1. Flax fibre has a complex morphological … (composition, structure, component).

2. The energy … (consumption, production, cost) is the most expensive component of processing flax.

3. Bleaching rove bobbins using H₂O₂ alone is not well suited for … (lignin degrading, rove processing, flax processing).

4. After … (chemical, mechanical, thermal) processing of the fibre rove bobbins are treated with caustic boil.

5. There are … (no, three, two) possible alternatives to chlorite treatment.

Exercise 11. Complete the sentences using information from the text.

1. Fibrils are cross-linked by pectin, hemicellulose and lignin, which have to …

2. Sprit is … plant material.

3. Rove bobbins are treated with caustic boil followed by peroxide and chlorite to … .

4. In textile processing the current emphasis is put on the reduction of … .

5. Sprit present on fibre could be broken down along with … .

6. The possibility of reusing the process liquor enhances … .

Exercise 12. Find the definitions to the words in the text:

1. Flax fibre is … .

2. Sprit is … .

Exercise 13. Find some keywords and expressions characterizing:

1. Fibrils.

2. Chlorite treatment.

3. Process water.

4. Enzyme treatment.