Tag: polymer

Questions Related to polymer

Which of the following polymers can be made by anionic addition polymerisation mechanism ?

chemistry petrochemicals and polymers addition polymerisation types of polymerisation reactions polymer

  1. PVC

  2. PAN

  3. Telfon

  4. PP

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Correct Option: A,B,C
Explanation:

Anionic addition polymerization is a form of chain-growth polymerization or addition polymerization that involves the polymerization of vinyl monomers with strong electronegative groups. This polymerization is carried out through a carbanion active species. 


Like all chain-growth polymerizations, it takes place in three steps: chain initiation, chain propagation and chain termination. 

Characteristics: In order for polymerization to occur with vinyl monomers, the substituents on the double bond must be able to stabilize a negative charge. Stabilization occurs through delocalization of the negative charge. The delocalisation of electron density can be done by Electron withdrawing group such as $CN$, $-F$, $-Cl$ etc.
The solvent is determined by the reactivity of both the initiator and carbanion of the propagating chain end.

Hence, polymers that can be made by anionic addition polymerisation mechanism are PVC, PAN and Teflon.

Monomer of $[NH - \overset{O}{\overset{||}{C}} - NH - CH _2] _n$ is :

chemistry petrochemicals and polymers addition polymerisation types of polymerisation reactions polymer

  1. Methanamine

  2. N-methyl urea

  3. Formaldehyde

  4. Ammonia

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Correct Option: C
Explanation:

Solution:- (C) Formaldehyde

It is urea formaldehyde polymer and it's monomers are urea and formaldehyde.

The main advantage of 'PVC' pipes for drainage is the feasibility of:

chemistry petrochemicals and polymers addition polymerisation types of polymerisation reactions polymer

  1. mechanical laying

  2. physical laying

  3. chemical laying

  4. both $B$ and $C$

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Correct Option: A

Which of the following alkenes is most reactive towards cationic polymerization?

chemistry petrochemicals and polymers addition polymerisation types of polymerisation reactions polymer

  1. ${ CH } _{ 2 }$ = ${ CHCH } _{ 3 }$

  2. ${ CH } _{ 2 }$ = $CHCl$

  3. ${ CH } _{ 2 }$ = ${ CHC } _{ 6 }{ H } _{ 5 }$

  4. ${ CH } _{ 2 }$ = ${ CHCOOCH } _{ 3 }$

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Correct Option: C
Explanation:

In cationic polymerization the most stable cation will show the highest reactivity.

The order of reactivity will be-

$CH _2 = CH-C _6H _5 > CH _2  = CHCH _3 > CH _2 = CHCl >CH _2 = CHCOOCH _3$

Option C is correct.

The commercial name of polyacrylonitrile is:

chemistry polymer polymers of commercial importance some commercially important polymers condensation polymers

  1. dacron

  2. orlon (acrilan)

  3. PVC

  4. bakelite

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Correct Option: B
Explanation:

The commercial name of polyacrylonitrile is orlon or acrilan,

The addition polymerisation of acrylonitrile in presence of a peroxide catalyst leads to the formation of polyacrylonitrile. Polyacrylonitrile is used as a substitute for wool in making commercial fibers.

Few polymers are matched with their uses. Point out the wrong match.

chemistry polymer polymers of commercial importance some commercially important polymers condensation polymers

  1. Polyester - Fabric, tyre cords, safety belts

  2. Nylon 6 - Ropes, tyre cords, fabrics

  3. Bakelite - Packaging industry, lubricant

  4. Teflon - Oil seals, gaskets, non-stick utensils

Show answer
Correct Option: C
Explanation:

Uses of bakelite:

  • For making combs, phonograph records, electrical switches,
  • For making handles of various utensils,
  • Paints

So the incorrect option is [C}.

Match the column I with column II and mark the appropriate choice.

Column I Column II
(A) Raincoats, hand bags (i) PHBV
(B) Laminated sheets (ii) PVC
(C) Television cabinets (iii) Urea-formaldehyde resin
(D) Orthopaedic devices (iv) Polystyrene
chemistry polymer polymers of commercial importance some commercially important polymers condensation polymers

  1. (A) $\rightarrow$ (i), (B) $\rightarrow$ (ii), (C) $\rightarrow$ (iii), (D) $\rightarrow$ (iv)

  2. (A) $\rightarrow$ (iv), (B) $\rightarrow$ (i), (C) $\rightarrow$ (ii), (D) $\rightarrow$ (iii)

  3. (A) $\rightarrow$ (ii), (B) $\rightarrow$ (iii), (C) $\rightarrow$ (iv), (D) $\rightarrow$ (i)

  4. (A) $\rightarrow$ (iii), (B) $\rightarrow$ (iv), (C) $\rightarrow$ (i), (D) $\rightarrow$ (ii)

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Correct Option: C
Explanation:
 Raincoats, handbags  (ii) PVC
 Laminated sheets  (iii) Urea-formaldehyde resin
 Television cabinets  (iv) Polystyrene
 Orthopedic devices  (i) PHBV

Uses of polyesters- it is crease resistant and is used in blending with cotton and wool fibers and also as glass reinforcing materials in safety helmets, etc.

So the correct option is [C}.

Novolac on heating with formaldehyde undergoes _______ to form an infusible solid mass called _______.

chemistry polymer polymers of commercial importance some commercially important polymers condensation polymers

  1. polymerization, melamine

  2. vulcanization, resin

  3. cross-liking, bakelite

  4. condensation, polystyrene

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Correct Option: C
Explanation:

On heating with formaldehyde undergoes crosslinking and form a thermosetting polymer named as$bakalite$.

These are obtained by the condensation reaction of phenol with formaldehyde in the presence of either an acid or a base catalyst. The reaction starts with the initial formation of $o-and/or p-hydroxymethylphenol$ derivatives, which further react with phenol to form compounds having rings joined to each other through –CH2 groups. The initial product could be a linear product – Novolac used in paints.
The correct option is [C].

What are blended fibres?

chemistry polymer polymers of commercial importance some commercially important polymers condensation polymers

  1. Mixture of two natural fibres

  2. Mixture of two synthetic fibre

  3. Mixture of natural and synthetic fibres

  4. All of above

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Correct Option: D
Explanation:

Blended fibres are made by combining various fibres to enhance the property of the product. For eg: spandex and cotton is a natural mix for sports clothing and undergarments to improve stretching properties and prevent odour. A blended fabric helps overcome the disadvantages of natural and synthetic fibre.

$C{F} _{2} = C{F} _{2}$ is a monomer of:

chemistry polymer polymers of commercial importance some commercially important polymers condensation polymers

  1. Teflon

  2. Orlon

  3. Polythene

  4. Nylon-6

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Correct Option: A
Explanation:

Tetrafluorothylene $C{F} _{2} = C{F} _{2}$ is a monomer of Teflon $ { \left( -C{ F } _{ 2 }-C{ F } _{ 2 }- \right)  } _{ n }$.


             $n  C{ F } _{ 2 } = C{ F } _{ 2 }   \rightarrow   { \left( -C{ F } _{ 2 }-C{ F } _{ 2 }- \right)  } _{ n }$