Chemistry

Polymers and Plastics

1,228 Questions

Polymers and plastics questions explore the properties, synthesis, and applications of various synthetic and natural polymers. Key topics include biodegradable plastics, vulcanization, and polymer nanocomposites. These concepts are frequently tested in science and engineering competitive exams.

Biodegradable plasticsPolymer nanocompositesVulcanization of rubberPolymer molecular weightAsphalt binders

Polymers and Plastics Questions

Multiple choice chemistry petrochemicals and polymers addition polymerisation types of polymerisation reactions polymer

Polystyrene is an example of ___.

  1. elastomer

  2. fibre

  3. cation polymerisation polymer

  4. thermosetting polymer
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

ELASTOMER  -  $Elastomers$ are rubber-like solids with elastic properties.
FIBRE  -  Fibre polymers are the thread forming solids with high tensile strength and high modulus.
THERMOSETTING  POLYMER  - These polymers are cross-linked or heavily branched molecules, which on heating undergo extensive cross-linking in moulds and again become infusible.
POLYSTYRENE - $Polystyrene$ is a thermoplastic polymer. It is formed by cation polymerisation. Hence, it is an example of a $cation$ $polymerisation$ $polymer$.

Multiple choice chemistry petrochemicals and polymers addition polymerisation types of polymerisation reactions polymer

The polymer used for post operative stitches is:

  1. glycolic acid

  2. poly lactic acid
  3. Nylon -$2$ - Nylon - $6$

  4. PHBV
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Polylactic acid is a thermoplastic aliphatic polyester derived from renewable resources
Polylactic acid is used for post operative stitches as it breaks down inside the body within $6$ months to $2$ years.

Multiple choice chemistry petrochemicals and polymers addition polymerisation types of polymerisation reactions polymer

Which polymer describes tail - to - tail addition? 

  1. $-CH _2-\underset{X}{\underset{|}{CH}}-CH _2-\underset{CH}{\underset{|}{X}}-$
  2. $-\underset{X}{\underset{|}{CH}}-CH _2-CH _2-\underset{X}{\underset{|}{CH}}-$
  3. $-CH _2-\underset{X}{\underset{|}{CH}}-\underset{X}{\underset{|}{CH}}-CH _2-$

  4. All of the above
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
In tail to tail polymerization, $-X$ is located such that it is separated by $H$ atoms.

i.e, $-\underset { | }{ CH } -{ CH } _{ 2 }-{ CH } _{ 2 }-\underset { | }{ CH } -$
          $X$                                    $X$
Multiple choice chemistry petrochemicals and polymers addition polymerisation types of polymerisation reactions polymer

Which statement about poly(chloroethene) is correct?

  1. The polymer can be cracked to produce chlorinated alkenes

  2. The polymer has harmless combustion products

  3. The polymer is readily biodegradable when buried
  4. The repeat unit of the polymer has an $M _r$ of $97$.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Polychloroethene is an addition polymer. Chloroethene can polymerise to form poly(chloroethene). Hence they can be cracked to produce chlorinated alkenes.

Multiple choice chemistry petrochemicals and polymers addition polymerisation types of polymerisation reactions polymer

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

  1. PVC

  2. PP

  3. HDPE

  4. LDPE
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

HDPE (high-density polyethene) and LDPE (low-density polyethene) polymerize by Ziegler-Natta Catalytic Polymerization reaction. 


PVC (polyvinyl chloride) polymerizes by radical polymerization. 

PP (polypropene) polymerizes by the cationic polymerization reaction.

Multiple choice chemistry petrochemicals and polymers addition polymerisation types of polymerisation reactions polymer

An example of chain-growth polymer is:

  1. Nylon - $6,6$

  2. Bakelite

  3. Terylene

  4. Teflon
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation
Chain-growth polymerization or chain polymerization is a polymerization technique where unsaturated monomer molecules add onto the active site of a growing polymer chain one at a time. Growth of the polymer occurs only at one (or possibly more) ends. Addition of each monomer unit regenerates the active site.
Polyethylene, polypropylene, polyvinyl chloride (PVC) and teflon  are common types of plastics made by chain-growth polymerization.

Hence, option D is correct.
Multiple choice chemistry petrochemicals and polymers addition polymerisation types of polymerisation reactions polymer

The monomer unit of PVC is:

  1. propene

  2. vinyl chloride

  3. vulcanised rubber

  4. none of the above
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
The monomer unit of PVC is vinyl chloride. The full form of PVC is Polyvinyl chloride.
$ \displaystyle  \underset {  \displaystyle  \text {vinyl chloride } }{   nCH _2=   \underset {   \underset {\displaystyle Cl}{|}  }{C} H} \xrightarrow { \text { polymerisation }}    \underset {  \displaystyle  \text { Polyvinyl chloride
} }{   (-CH _2-   \underset {   \underset {\displaystyle Cl}{|}  }{C} H -) _n}$
Multiple choice chemistry petrochemicals and polymers addition polymerisation types of polymerisation reactions polymer

The other names of PVC is/are:

  1. polychloroethylene

  2. polyvinylidene chloride

  3. polychlororthene

  4. none of these
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The full form of PVC is Polyvinyl chloride. It is polymer of vinyl chloride.
$ \displaystyle  \underset {  \displaystyle  \text {vinyl chloride } }{   nCH _2=   \underset {   \underset {\displaystyle Cl}{|}  }{C} H} \xrightarrow { \text { polymerisation }}    \underset {  \displaystyle  \text { Polyvinyl chloride
} }{   (-CH _2-   \underset {   \underset {\displaystyle Cl}{|}  }{C} H -) _n}$

Multiple choice chemistry petrochemicals and polymers addition polymerisation types of polymerisation reactions polymer

The full form of PVC is:

  1. polyvulcanised chloride

  2. pure vulcanised chlorine

  3. polyvinyl chloride

  4. none of the above
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The full form of PVC is Polyvinyl chloride. It is polymer of vinyl chloride.
$ \displaystyle  \underset {  \displaystyle  \text {vinyl chloride } }{   nCH _2=   \underset {   \underset {\displaystyle Cl}{|}  }{C} H} \xrightarrow { \text { polymerisation }}    \underset {  \displaystyle  \text { Polyvinyl chloride
} }{   (-CH _2-   \underset {   \underset {\displaystyle Cl}{|}  }{C} H -) _n}$

Multiple choice chemistry petrochemicals and polymers addition polymerisation types of polymerisation reactions polymer

Which of the following is added to improve flexibility of PVC?

  1. Rubber

  2. Plasticizers

  3. Ethane

  4. Flexicizers
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

With some additives in PVC, the physical and mechanical properties are improved.

Different additives such as plasticizers, fillers, stabilizer, pigments were mixed. These are added in order to increase the elongation i.e; its flexibility.

Multiple choice chemistry petrochemicals and polymers addition polymerisation types of polymerisation reactions polymer

PVC is an example of which kind of plastic?

  1. Thermoplastic

  2. Thermosetting

  3. It is not a type of plastic
  4. Both $A$ and $B$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

PVC (polyvinyl chloride) is thermoplastic polymer. Its properties are between elastomers and fibers. On heating, it becomes soft and on cooling, become hard. It can be remoulded and recycled.

Multiple choice chemistry petrochemicals and polymers addition polymerisation types of polymerisation reactions polymer

Which of the following polymer has the tendency of decomposing before melting ?

  1. Polystyrene

  2. PVC

  3. Nylon

  4. None of the above
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation
Thermosetting polymers such as Bakelite have the tendency of decomposing before melting. Thermoplastic polymers (such as PVC (polyvinyl chloride), polystyrene ) on heating, becomes soft and on cooling, become hard. They can be remolded and recycled. Their properties are between elastomers and fibers.
There is no thermosetting given in the option, all are thermoplastic.
Hence, the correct option is D.