Structural, Thermal and Microscopic Characterization - Polymer Characterization - Engineering Sciences Previous Year Questions

1

2009 · Engineering Sciences · Polymer Characterization · Structural, Thermal and Microscopic Characterization

Engineering Sciences (XE) 2009

The fractional crystallinity of the sample is

A

0.23

B

0.36

C

0.40

D

0.43

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2

2009 · Engineering Sciences · Polymer Characterization · Structural, Thermal and Microscopic Characterization

Engineering Sciences (XE) 2009

The heat of fusion of the PET crystalline phase is

A

21.8 J/g

B

136.5 J/g

C

68.2 J/g

D

158.3 J/g

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3

2014 · Engineering Sciences · Polymer Characterization · Structural, Thermal and Microscopic Characterization

Engineering Sciences (XE) 2014

Calculate the mass percent of the crystalline phase in a polymer sample of density 975 kg/m³. The density of amorphous phase is 866 kg/m³ and that of the crystalline phase is 996 kg/m³.

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4

2014 · Engineering Sciences · Polymer Characterization · Structural, Thermal and Microscopic Characterization

Engineering Sciences (XE) 2014

Match the following changes observed in the calorimetric analysis of a polymer sample when heat flow (y-axis) is plotted against temperature (x-axis):
P. step increase in heat flow    1. crystallization
Q. exothermic peak              2. melting
R. endothermic peak           3. glass transition

A

P-1, Q-2, R-3

B

P-2, Q-1, R-3

C

P-3, Q-1, R-2

D

P-3, Q-2, R-1

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5

2015 · Engineering Sciences · Polymer Characterization · Structural, Thermal and Microscopic Characterization

Engineering Sciences (XE) 2015

Match the characterization technique with the polymer property it is used to determine

Technique	Property
P. X-ray diffraction	1. Melting temperature
Q. Differential scanning calorimetry	2. Crystallinity & crystal size
R. Thermogravimetric analysis	3. Glass transition temperature
S. Dynamic mechanical analysis	4. Ash content

A

P-3; Q-1; R-4; S-2

B

P-3; Q-4; R-2; S-1

C

P-2; Q-4; R-1; S-3

D

P-2; Q-1; R-4; S-3

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6

2016 · Engineering Sciences · Polymer Characterization · Structural, Thermal and Microscopic Characterization

Engineering Sciences (XE) 2016

Oxygen is permeating through an EVOH film of thickness ‘t’ and solubility coefficient ‘S’. If diffusivity of oxygen through the film is ‘D’, then permeability of oxygen through the film will be _____.

A

D/t

B

D/S

C

D × S

D

S/D

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7

2016 · Engineering Sciences · Polymer Characterization · Structural, Thermal and Microscopic Characterization

Engineering Sciences (XE) 2016

Dynamic mechanical analysis of polystyrene (T_g = 100 °C) measured at a frequency of 1 Hz shows the damping peak at 110 °C. If the measurement is made at 10² Hz, then the peak temperature (°C) will be

A

123.2

B

133.2

C

143.2

D

153.2

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8

2017 · Engineering Sciences · Polymer Characterization · Structural, Thermal and Microscopic Characterization

Engineering Sciences (XE) 2017

The two characterization techniques which can be used to determine degree of crystallinity of a polymer are
P. Scanning Electron Microscopy
Q. Thermogravimetric Analysis
R. Wide Angle X-Ray Diffraction
S. Differential Scanning Calorimetry

A

P&R

B

Q&R

C

R&S

D

Q&S

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9

2017 · Engineering Sciences · Polymer Characterization · Structural, Thermal and Microscopic Characterization

Engineering Sciences (XE) 2017

The density of polyethylene crystals is 998 kg/m³ and that of totally amorphous polyethylene is 886 kg/m³. If the density of a polyethylene sample is 949 kg/m³, the crystallinity in volume fraction is _____ % (round off final answer to two digits after decimal place).

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10

2018 · Engineering Sciences · Polymer Characterization · Structural, Thermal and Microscopic Characterization

Engineering Sciences (XE) 2018

The solubility parameter of a polymer having cohesive energy density (E_coh) 43870 J/mol and molar volume (V) 136 cm³/mol is ________ (J/cm³)^1/2.

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11

2018 · Engineering Sciences · Polymer Characterization · Structural, Thermal and Microscopic Characterization

Engineering Sciences (XE) 2018

If the heat of fusion of 100 % crystalline polyethylene is 290 mJ/mg, a sample of polyethylene with heat of fusion of 141 mJ/mg will have_______ % crystallinity.

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12

2019 · Engineering Sciences · Polymer Characterization · Structural, Thermal and Microscopic Characterization

Engineering Sciences (XE) 2019

Glass transition temperature of a polymer can be determined by

A

Thermo-gravimetric analysis

B

Raman spectroscopy

C

NMR spectroscopy

D

Differential scanning calorimetry

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13

2019 · Engineering Sciences · Polymer Characterization · Structural, Thermal and Microscopic Characterization

Engineering Sciences (XE) 2019

Match the following polymers with their characteristic infrared (IR) stretching frequency:

Polymer	IR stretching frequency (cm⁻¹)
P. Polystyrene	1. ~2242
Q. Polyacrylonitrile	2. ~1733
R. Poly(ethylene terephthalate)	3. ~3392
S. Poly(vinyl alcohol)	4. ~3100

A

P-2, Q-3, R-1, S-4

B

P-2, Q-1, R-4, S-3

C

P-4, Q-2, R-3, S-1

D

P-4, Q-1, R-2, S-3

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14

2020 · Engineering Sciences · Polymer Characterization · Structural, Thermal and Microscopic Characterization

Engineering Sciences (XE) 2020

Match the appropriate characterization technique in Column A used to determine the polymer attributes in Column B

A

P-2, Q-3, R-4, S-1

B

P-3, Q-4, R-1, S-2

C

P-2, Q-4, R-1, S-3

D

P-4, Q-1, R-3, S-2

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15

2022 · Engineering Sciences · Polymer Characterization · Structural, Thermal and Microscopic Characterization

Engineering Sciences (XE) 2022

From the dynamic mechanical analysis of a polymer sample with a phase angle of 30°, the relationship between storage modulus (E') and loss modulus (E") can be expressed as

A

E' = √3 E"

B

2E' = √3 E"

C

E" = √3 E'

D

2E" = √3 E'

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16

2022 · Engineering Sciences · Polymer Characterization · Structural, Thermal and Microscopic Characterization

Engineering Sciences (XE) 2022

Match the polymers with their characteristic infrared (IR) stretching frequency

A

P-4; Q-3; R-2; S-1

B

P-3; Q-4; R-2; S-1

C

P-3; Q-4; R-1; S-2

D

P-3; Q-2; R-4; S-1

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17

2022 · Engineering Sciences · Polymer Characterization · Structural, Thermal and Microscopic Characterization

Engineering Sciences (XE) 2022

The enthalpy of fusion for a polymer is found to decrease from 135.6 J g⁻¹ to 120 J g⁻¹ after five years of use. If the enthalpy of fusion of the same polymer with 100% crystallinity is 290 J g⁻¹, then the loss in crystallinity after five years is __________ % (rounded off to one decimal place).

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18

2024 · Engineering Sciences · Polymer Characterization · Structural, Thermal and Microscopic Characterization

Engineering Sciences (XE) 2024

Differential scanning calorimetry involves measurement of

A

weight change

B

entropy

C

heat

D

vapour pressure

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19

2024 · Engineering Sciences · Polymer Characterization · Structural, Thermal and Microscopic Characterization

Engineering Sciences (XE) 2024

If a given poly(ethylene) sample with specific volume, v = 1.042 × 10^{-3} m³ kg^{-1} shows: specific volume of the crystalline fraction, v_c = 0.989 × 10^{-3} m³ kg^{-1} and specific volume of the amorphous fraction, v_a = 1.160 × 10^{-3} m³ kg^{-1}, then the % crystallinity (based on mass fraction) of the poly(ethylene) sample is ______ % (rounded off to the nearest integer).

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20

2025 · Engineering Sciences · Polymer Characterization · Structural, Thermal and Microscopic Characterization

Engineering Sciences (XE) 2025

Which option(s) correctly match(es) the Polymer property with its appropriate Units?

Polymer property		Units
P	Hildebrand solubility parameter	1	Pa
Q	Loss modulus	2	J m-3
R	Toughness	3	(MPa)1/2
S	Flexural strength	4	Kg m-1 s-2

A

P-2; Q-1; R-3; S-4

B

P-2; Q-4; R-3; S-1

C

P-3; Q-1; R-2; S-4

D

P-3; Q-4; R-2; S-1

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