Pune University BE Polymer Engineering Rubber Technology Question Papers

Pune University BE Polymer Engineering Rubber Technology

Question Papers

B.E. (Polymer) RUBBER TECHNOLOGY (2008 Pattern) (Elective – IV) (Sem. – II)

Time :3 Hours]                                                                                              [Max. Marks :100

Instructions to the candidates:-

1)           Answer 3 questions from Section I and 3 questions from Section II.

2)           Answers to the two sections should be written in separate books.

3)           Neat diagrams must be drawn wherever necessary.

4)           Pigures to the right indicate full marks.

5)           Your answers will be valued as a whole.

6)           Use fo logarithmic tables slide rule, Mollier charts, electronic pocket calculator and steam tables is allowed.

7)           Assume suitable data, if necessary.

SECTION – I

QIA a) What are the molecular-structural requirements for a material to act as a

rubber?                                                                                                                 [6]

b)        Explain the thermodynamic theory of rubber elasticity.                     [6]

c)         Discuss the various stages involved in raw rubber technology.         [6]

OR

Q2) a) Discuss the stress strain relationship for vulcanized and unvulcanized

rubbers.                                                                                                                [6]

b)        Explain the following terms.                                                                    [6]

i)              Rebound resilience

ii)            Storage hardening and crystallization of Natural rubber.

c)         Discuss the plysics of raw and vulcanized rubber.                               [6]

Q3) a) State the different types of C-blacks and differentiate between then. [4]

b)          What is the need for addition of vulcanising agents? State the different types of vulcanising agents with examples. Also explain the need and mechanism of functioning of activators and accelerators with two examples of each.                        [6]

 

c)         Explain the need for addition, mechanism of functioning and two examples of each of the following additives w.r.t. rubbers.                                                            [6]

i)             Peptizers

ii)           Tackifiers

iii)        Blowing agent

OR

Q4) a) Discuss the basic principles used in compounding of rubber. List the various ingredients used in rubber compounding. Give the role of each ingredients with suitable examples.    [6]

b)        Write a short note on ‘fillers’ used in a rubber compound and their effect on the properties of the compound.                                                                     [6]

c)         What is mastication of rubbers? How is it carried out? Discuss w.r.t. Natural rubber.                                                                                                                      [R]

Q5) a) What is vulcanisation? Explain the process of vulcanising giving chemical reactions for at least three commercial elastomers.                                                                  [R]

b)        Discuss the factors affecting the process of vulcanisation. State 8 discuss various techniques of vulcanisation.                                                                     [6]

c)        Draw and explain the rheometer cure curve. Explain its significance. [6]

OR

Q6) a) Write a short note on the Mooney viscometer 8 plastometer w.r.t. rubbers.                                                                                                                [6]

b)        List 8 discuss the different types of vulcanising agents used with rubbers. [R]

c)        Discuss the kinetics of vulcanisation.                                                             [6]

SECTION – II

Q7) a) List the different types of roll arrangements used in calendaring. Explain roll chambering.                                                                                                                               [6]

b)        What is roll bending in calendaring? What are the remedies to overcome the same? [8]

c)        Discuss compression molding process w.r.t rubbers.                                 [R]

OR

Explain the process of injection molding of rubbers.                                  [8]

List the different types of extruders used with rubbers.                              [4]

What are the advantages and disadvantages of injection Molding as compared to compression molding of rubbers.                                                                                            [6]

List the various components forming a tyre structure and explain the function of each component. List the rubbers used in tyre manufacture. [6]

Define “Cellular rubber”. What are the 3 main classes of cellular rubber? Differentiate between them.                                                                                                                     [6]

With the help of a neat sketch list the various constructional elements of a cable stating the function of each element.                                                                                                 [4]

OR

Explain the process for manufacture of rubber conveyor belts. State the applications of rubber conveyor belts.                                                                                                    [6]

Explain the straight dipping process for manufacture of latex gloves. [6]

Discuss the construction of a rubber hose. State the materials used for making rubber hoses.     [4]

Write a short note on tests carried out on raw rubbers.                               [6]

State 2 applications in which the rubber product is tested for abrasion. Explain the procedure to carry out the test.                                                                                                [6]

Define the term “resilience” and explain the test used to measure rebound resilience.      [4]

OR

Define “fatigue”. Discuss the test procedure, specimen size used to carry out the test for fatigue.                                                                                                                               [6]

Discuss the test procedure to determine low temperature properties in case of rubbers.   [6]

How is ash content and moisture content determined in case of rubbers? [4]

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