Download GTU (Gujarat Technological University) BE/BTech (Bachelor of Engineering / Bachelor of Technology) 2019 Winter 4th Sem New 2142602 Natural Rubber Science And Technology Previous Question Paper
Seat No.: ________ Enrolment No.___________
GUJARAT TECHNOLOGICAL UNIVERSITY
BE - SEMESTER ? IV (New) EXAMINATION ? WINTER 2019
Subject Code: 2142602 Date: 14/12/2019
Subject Name: Natural Rubber Science & Technology
Time: 10:30 AM TO 01:00 PM Total Marks: 70
Instructions:
1. Attempt all questions.
2. Make suitable assumptions wherever necessary.
3. Figures to the right indicate full marks.
Q.1 (a) What is the difference between network structure of conventional and liquid
elastomers?
03
(b) Describe the suitable method to achieve carbon black dispersion in liquid
polybutadiene rubber.
04
(c) Explain in detail about RSS and Pale Crepe grades of natural rubber. 07
Q.2 (a) Write about the effect of compounding ingredients on diffusion process. 03
(b) Describe the ?storage hardening? as an important phenomenon related with
natural rubber.
04
(c) Discuss in detail about the general features of wax blooming. 07
OR
(c) Explain the effect of ?nature of liquid? and ?nature of rubber? in the diffusion of
hydrocarbon liquids and oils.
07
Q.3 (a) List the types of chemical modification on natural rubber. 03
(b) Why natural rubber is considered to be very reactive polymer? Describe with
suitable explanation.
04
(c) Write a short note on Grafting chemistry. 07
OR
Q.3 (a) Define the purpose of chemical modification of natural rubber. 03
(b) Write about [3 + 2] cycloaddition reaction mechanism with suitable example. 04
(c) Explain the tensile stress-strain behaviour of graft copolymer. 07
Q.4 (a) Write about Hysteresis. 03
(b) How can you measure puncture strength? Describe with schematic view of the
test.
04
(c) Discuss in detail about the experimental method for the measurement of elastic
modulus throughout the crystallization process.
07
OR
Q.4 (a) Which kind of changes arise to rubber products due to the effect of
environmental factors?
03
(b) Describe the creep and stress relaxation properties for vulcanized rubber. 04
(c) Explain in detail about the tensile modulus variation with crystallization time
and crystallization temperature respectively.
07
Q.5 (a) What do you mean by SAM and SAMI related with asphalt rubber in paving
application?
03
(b) Write about the different types of reclaimed rubber. 04
(c) List the methods used for preparation of powdered rubber. Explain in detail
about any two.
07
OR
Q.5 (a) List the uses of reclaimed rubber. 03
(b) Write about Heater process for the production of reclaimed rubber. 04
(c) Discuss about the advantages of powdered rubbers. 07
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This post was last modified on 20 February 2020