Anna University Dyeing of Cellulosic Fibres I Exam Paper
Time : 3 Hours Max : 100 Marks
PART – A Answer the following questions :- (10 x 2 = 20)
1. What do you understand by the terms, “Affinity”, “Substantivity”?
2. “Reactivity” & “Exhaustion”, – Define.
3. Highlight classification of dyes according to the mode and methods of application.
4. State the influences of pre treatments on dyeing properties.
5. State the various after treatments to improve fastness properties of direct dyed Cellulosic materials.
6. How direct dyes are classified?
7. What do you mean by “Wash fastness”.
8. What is the chemistry of “Reactive Dyes”?
9. State the various practical problems in reactive dyeing and remedies.
10. List out various methods of application of vat dyeing.
PART – B Answer Five of the following questions :- (5 x 16 = 80)
11.i) Explain the mechanisms of dyeing techniques such as mechanical deposition and chemical fixation. (12)
ii) Highlight the general properties of direct dyes. (4)
i)Explain in detail the principles and method of application of direct dyes on Cellulosic materials. (10)
ii)Discuss the various problems in direct dyeing. (6)
i)Explain the various shop floor practices in reactive dyeing of Cellulosic materials. (8)
ii) What are HE and Vinyl sulphone reactive dyes? (4)
iii) Explain the concept of Hot brand and Cold Brand dyes. (4)
i)Discuss in detail the principal steps involved in reactive dyeing (10)
ii) Explain the basic concepts of Dye and Pigment. (6)
i) Explain the method of application of vat dyes on Cellulosic yarn and fabric. (10)
ii) Highlight the general properties of vat dyes. (6)
i) Discuss the various practical problems in vat dyeing. (6)
ii) Explain the process “Stripping of vat dyes”. (6)
iii) What is “Vatting”? (4)
i) Explain the concepts of exhaust and padding techniques of dyeing. (8)
ii) Explain the influence of pretreatment on dyeing properties. (8)
i) Explain in detail the principles steps involved in dyeing with solublised vat dyes. (10)
ii) Explain the general properties of solublised vat dyes. (6)
i) Distinguish between “Vat dyes” and “Solublised Vat dyes”. (4)
ii) List out problem and their remedies in solublised vat dyes. (6)
iii) Highlight the chemistry of solublised vat dyes. (6)