Polymerization Mechanisms and Kinetics - Polymer Chemistry - Engineering Sciences Previous Year Questions

1

2008 · Engineering Sciences · Polymer Chemistry · Polymerization Mechanisms and Kinetics

Engineering Sciences (XE) 2008

The average degree of polymerization of Polypropylene associated with an average molecular weight of 36000 amu is (atomic masses of C and H are 12 and 1 amu, respectively)

A

1286

B

857

C

360

D

346

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2

2008 · Engineering Sciences · Polymer Chemistry · Polymerization Mechanisms and Kinetics

Engineering Sciences (XE) 2008

Among the polymerization methods listed below, the one that is likely to give a polydispersity close to unity is

A

anionic polymerization

B

cationic polymerization

C

condensation polymerization

D

radical polymerization

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3

2008 · Engineering Sciences · Polymer Chemistry · Polymerization Mechanisms and Kinetics

Engineering Sciences (XE) 2008

Which of the following monomers is used in the synthesis of poly(vinyl alcohol)

A

CH3CH2OH

B

CH2=CH(OH)

C

CH2=CH-O-CO-CH3

D

CH2=CH-CO2H

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4

2008 · Engineering Sciences · Polymer Chemistry · Polymerization Mechanisms and Kinetics

Engineering Sciences (XE) 2008

2,2'-azobisisobutyronitrile (AIBN) is an initiator used in the free radical polymerization of methyl methacrylate (MMA). When the concentration of AIBN is doubled maintaining MMA concentration unchanged, the rate of propagation

A

is doubled

B

increases by a factor of √2

C

is reduced by half

D

decreases by a factor of √2

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5

2008 · Engineering Sciences · Polymer Chemistry · Polymerization Mechanisms and Kinetics

Engineering Sciences (XE) 2008

The polydispersity index at stoichiometric conditions would be

A

1.90

B

1.95

C

1.85

D

1.99

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6

2008 · Engineering Sciences · Polymer Chemistry · Polymerization Mechanisms and Kinetics

Engineering Sciences (XE) 2008

Match the items in Group I with the most appropriate items in Group II

A

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

B

P-5, Q-4, R-1, S-2

C

P-3, Q-4, R-5, S-2

D

P-5, Q-2, R-1, S-4

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7

2008 · Engineering Sciences · Polymer Chemistry · Polymerization Mechanisms and Kinetics

Engineering Sciences (XE) 2008

The end-groups in a polymer sample prepared by using ROOH/Fe^{2+} (where R = alkyl) as the initiator system is

A

Fe^{2+}

B

-OR

C

-OH

D

Fe^{3+}

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8

2009 · Engineering Sciences · Polymer Chemistry · Polymerization Mechanisms and Kinetics

Engineering Sciences (XE) 2009

During chain growth polymerization, the molecular weight of the polymer

A

increases with conversion

B

decreases with conversion

C

does not change with conversion

D

first increases and then decreases with conversion

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9

2009 · Engineering Sciences · Polymer Chemistry · Polymerization Mechanisms and Kinetics

Engineering Sciences (XE) 2009

Based on the solubility parameter (δ) the best solvent for polyethylene (δ = 16.2 MPa1/2) is

A

tetrahydrofuran (δ = 20.3 MPa^1/2)

B

toluene (δ = 18.3 MPa^1/2)

C

acetone (δ = 19.9 MPa^1/2)

D

methanol (δ = 29.7 MPa^1/2)

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10

2009 · Engineering Sciences · Polymer Chemistry · Polymerization Mechanisms and Kinetics

Engineering Sciences (XE) 2009

Match the polymerization initiator with the respective process.
Initiator
P. benzyl lithium
Q. tropylium chloride
R. AIBN
S. TiCl₄/Al(Et)₃
Process
1. coordination polymerization
2. anionic polymerization
3. cationic polymerization
4. radical polymerization

A

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

B

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

C

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

D

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

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11

2009 · Engineering Sciences · Polymer Chemistry · Polymerization Mechanisms and Kinetics

Engineering Sciences (XE) 2009

At the start of a step growth polymerization there are $N_0$ moles of monomer A (molecular weight $M_A$) and $N_0$ moles of monomer B (molecular weight $M_B$). At the end of the polymerization there are $N$ moles of polymer chains. Assuming no condensation product, the number of average molecular weight is

A

$2N_0(M_A + M_B) / N$

B

$N_0(M_A + M_B) / N$

C

$N_0(M_A + M_B) / 2N$

D

$N_0^2(M_A + M_B) / N^2$

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12

2010 · Engineering Sciences · Polymer Chemistry · Polymerization Mechanisms and Kinetics

Engineering Sciences (XE) 2010

Match the items in Group I for their correctness with the corresponding appropriate terms given in Groups II and III.

A

P:1,X

B

P:2,X

C

Q:1,X

D

Q:2,Y

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13

2010 · Engineering Sciences · Polymer Chemistry · Polymerization Mechanisms and Kinetics

Engineering Sciences (XE) 2010

A small molecule is eliminated as a byproduct during the synthesis of

A

Polycaprolactone

B

Poly(ethylene terephthalate)

C

Styrene butadiene copolymer

D

Polytetrafluoroethylene

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14

2010 · Engineering Sciences · Polymer Chemistry · Polymerization Mechanisms and Kinetics

Engineering Sciences (XE) 2010

For 100% polyesterification, the X̅_n will be

A

100

B

1000

C

10000

D

∞

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15

2010 · Engineering Sciences · Polymer Chemistry · Polymerization Mechanisms and Kinetics

Engineering Sciences (XE) 2010

The percentage conversion of functional groups required to obtain the polyester with a molecular weight of 24000 g/mol will be

A

99

B

96

C

93

D

90

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16

2011 · Engineering Sciences · Polymer Chemistry · Polymerization Mechanisms and Kinetics

Engineering Sciences (XE) 2011

Monomers that undergo free radical polymerization have

A

one hydroxyl and one carboxylic group

B

double bonds

C

one amine group and one carboxylic group

D

two amine groups

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17

2011 · Engineering Sciences · Polymer Chemistry · Polymerization Mechanisms and Kinetics

Engineering Sciences (XE) 2011

In the polymerization of phthalic anhydride (3 moles) and glycerols (3 moles), the average functionality of the reacting system is

A

1.2

B

4.2

C

3.8

D

2.5

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18

2011 · Engineering Sciences · Polymer Chemistry · Polymerization Mechanisms and Kinetics

Engineering Sciences (XE) 2011

Polyurethane is formed by

A

self condensation of polyols

B

self condensation of diisocyane

C

reaction of polyol and diisocyanate

D

reaction of polyol with adipic acid

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19

2011 · Engineering Sciences · Polymer Chemistry · Polymerization Mechanisms and Kinetics

Engineering Sciences (XE) 2011

In the step-growth polymerization of phenol with formaldehyde the functionality of phenol is

A

2

B

5

C

4

D

3

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20

2011 · Engineering Sciences · Polymer Chemistry · Polymerization Mechanisms and Kinetics

Engineering Sciences (XE) 2011

The solubility parameter of polystyrene is 9.1 (cal/cm^3)^{1/2}, the solubility parameter of n-hexane is 7.3 (cal/cm^3)^{1/2} and that of benzene is 9.2 (cal/cm^3)^{1/2}. Then polystyrene will

A

dissolve in n-hexane

B

not dissolve in 80:20 mixture of n-hexane and benzene

C

not dissolve in benzene

D

dissolve in benzene

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