Molecular Weight and Polymer Transitions - Polymer Characterization - Engineering Sciences Previous Year Questions

1

2008 · Engineering Sciences · Polymer Characterization · Molecular Weight and Polymer Transitions

Engineering Sciences (XE) 2008

The molecular weight of the polymer is

A

4.5 x 10⁵

B

6.1 x 10⁵

C

3.2 x 10⁶

D

7.9 x 10⁵

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2

2008 · Engineering Sciences · Polymer Characterization · Molecular Weight and Polymer Transitions

Engineering Sciences (XE) 2008

The specific viscosity of the above polymer is

A

0.73

B

1.12

C

0.89

D

2.30

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3

2008 · Engineering Sciences · Polymer Characterization · Molecular Weight and Polymer Transitions

Engineering Sciences (XE) 2008

A polymer sample has 3 molecules with molecular weights 1×10^5, 2×10^5 and 3×10^5 g mol^{-1} respectively. The weight average molecular weight of the sample is

A

2.99×10^5 g mol^{-1}

B

2.66×10^5 g mol^{-1}

C

2.33×10^5 g mol^{-1}

D

2.00×10^5 g mol^{-1}

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4

2009 · Engineering Sciences · Polymer Characterization · Molecular Weight and Polymer Transitions

Engineering Sciences (XE) 2009

For any polymer, the number average molecular weight (M_n), weight average molecular weight (M_w) and viscosity average molecular weight (M_v), in general, obey the following relationship :

A

M_n > M_w > M_v

B

M_v > M_n > M_w

C

M_w > M_v > M_n

D

M_v > M_w > M_n

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5

2010 · Engineering Sciences · Polymer Characterization · Molecular Weight and Polymer Transitions

Engineering Sciences (XE) 2010

A high molecular weight polyethylene has an average molecular weight of 560,000g/mol. Its average degree of polymerization is

A

15,000

B

18,660

C

19,310

D

20,000

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6

2010 · Engineering Sciences · Polymer Characterization · Molecular Weight and Polymer Transitions

Engineering Sciences (XE) 2010

The glass transition temperature of the polymeric plasticizer will be

A

-84 °C

B

-74 °C

C

74 °C

D

84 °C

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7

2010 · Engineering Sciences · Polymer Characterization · Molecular Weight and Polymer Transitions

Engineering Sciences (XE) 2010

The number average molecular weight, M̅_n (g/mol) of the polymer is

A

1.02 × 10⁵

B

0.99 × 10⁵

C

0.63 × 10⁵

D

0.55 × 10⁵

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8

2010 · Engineering Sciences · Polymer Characterization · Molecular Weight and Polymer Transitions

Engineering Sciences (XE) 2010

The polydispersity index of the polymer is

A

2.59

B

1.87

C

1.72

D

1.59

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9

2011 · Engineering Sciences · Polymer Characterization · Molecular Weight and Polymer Transitions

Engineering Sciences (XE) 2011

If the average degree of polymerisation of a polyvinyl chloride (PVC) polymer is 2000, then its average molecular weight (in g mol⁻¹) is

A

125000

B

119000

C

56000

D

2000

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10

2011 · Engineering Sciences · Polymer Characterization · Molecular Weight and Polymer Transitions

Engineering Sciences (XE) 2011

A mixture consists of 10 moles of dimer, 15 moles of trimer, 20 moles of tetramer and 5 moles of pentamer. The average chain length of the mixture is

A

3.4

B

8.5

C

6.8

D

1.7

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11

2011 · Engineering Sciences · Polymer Characterization · Molecular Weight and Polymer Transitions

Engineering Sciences (XE) 2011

The glass transition temperature (Tg) is governed by

A

translational motion of entire molecule

B

long cooperative wriggling motion of 40 to 50 C-C bonds

C

short cooperative motion of 5 to 6 bonds of the molecules

D

vibration of carbon atoms of the polymer molecules

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12

2012 · Engineering Sciences · Polymer Characterization · Molecular Weight and Polymer Transitions

Engineering Sciences (XE) 2012

The unit of intrinsic viscosity is

A

dl/g

B

g/dl

C

poise

D

g/mol

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13

2012 · Engineering Sciences · Polymer Characterization · Molecular Weight and Polymer Transitions

Engineering Sciences (XE) 2012

If the activation energy for relaxation is 30 KJ/mol, the relaxation time at 35°C will be

A

30.5 days

B

35.5 days

C

40.5 days

D

45.5 days

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14

2012 · Engineering Sciences · Polymer Characterization · Molecular Weight and Polymer Transitions

Engineering Sciences (XE) 2012

The z-average molecular weight, \( \overline{M}_z \) can be estimated using

A

End group analysis

B

Osmometry

C

Viscometry

D

Ultracentrifugation

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15

2012 · Engineering Sciences · Polymer Characterization · Molecular Weight and Polymer Transitions

Engineering Sciences (XE) 2012

If the mixture contains equal number of molecules of A, B and C, the weight average molecular weight, \(\overline{M_w}\) will be

A

\(1.93 \times 10^4\) g mol\(^{-1}\)

B

\(2.13 \times 10^4\) g mol\(^{-1}\)

C

\(2.33 \times 10^4\) g mol\(^{-1}\)

D

\(2.53 \times 10^4\) g mol\(^{-1}\)

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16

2012 · Engineering Sciences · Polymer Characterization · Molecular Weight and Polymer Transitions

Engineering Sciences (XE) 2012

If the mixture contains equal masses of A, B and C, then the number average molecular weight, \(\overline{M_n}\) will be

A

\(1.64 \times 10^4\) g mol\(^{-1}\)

B

\(1.74 \times 10^4\) g mol\(^{-1}\)

C

\(1.84 \times 10^4\) g mol\(^{-1}\)

D

\(1.94 \times 10^4\) g mol\(^{-1}\)

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17

2013 · Engineering Sciences · Polymer Characterization · Molecular Weight and Polymer Transitions

Engineering Sciences (XE) 2013

The relative viscosity of a 1% solution (weight/volume) of a given polymer was found to be 1.1. The inherent viscosity of this polymer will be

A

0.065 dl/g

B

0.075 dl/g

C

0.085 dl/g

D

0.095 dl/g

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18

2014 · Engineering Sciences · Polymer Characterization · Molecular Weight and Polymer Transitions

Engineering Sciences (XE) 2014

The estimation of the molecular weight of a polymer by gel permeation chromatography (GPC) is based on its

A

polarity

B

size

C

adsorption to stationary phase

D

crystallinity

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19

2014 · Engineering Sciences · Polymer Characterization · Molecular Weight and Polymer Transitions

Engineering Sciences (XE) 2014

A polymer solution is made by dissolving 5 g of polymer in 1000 ml of solvent. The flow time of the solvent and that of the polymer solution between two appropriate marks in a viscometer are 40 s and 60 s, respectively. The reduced viscosity (in dl.g⁻¹) of the polymer solution is:

A

0.25

B

0.50

C

1.0

D

1.5

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20

2015 · Engineering Sciences · Polymer Characterization · Molecular Weight and Polymer Transitions

Engineering Sciences (XE) 2015

Weight average molecular weight can be determined by

A

Osmometry

B

Ebulliometry

C

End group analysis

D

Light scattering

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