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

Which of the following statements is/are true?

  1. Polycaprolactam has higher Tm than polycaprolactone.
  2. Polyethylene oxide has a higher crystalline melting temperature than polyethylene.
  3. Poly(1,4-cis-butadiene) has higher Tg than Poly(1,4-trans-butadiene).

  1. Only 1

  2. Only 2

  3. Only 3

  4. Only 1 and 2

  5. Only 2 and 3
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The densities of the interunit linkages in polycaprolactone (ester units) and polycaprolactam (amide units) are the same. However, the amide units are more polar than the ester units. Consequently, polycaprolactam (226° C) has a much higher Tm than polycaprolactone (61° C).

Multiple choice

Which of the following statements are incorrect?

P. Nylon 2–nylon 6 copolymer is non-biodegradable. Q. Glyptal is the addition polymer of ethylene glycol and phthalic acid. R. Urea formaldehyde resin is used in the making of unbreakable cups and laminated sheets. S. Bakelite is the condensation polymer of phenol and formaldehyde.

  1. Only P and Q

  2. Only P and R

  3. Only P and S

  4. Only Q and R

  5. Only Q and S
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Nylon 2–nylon 6 is an alternating polyamide copolymer of glycine and amino caproic acid and is biodegradable. Glyptal is the condensation polymer of ethylene glycol and phthalic acid.

Multiple choice

Which of the following polymers is/are obtained by chain growth polymerisation?

  1. Dacron,
  2. LDPE,
  3. Nylon, 6-6,
  4. PAN,
  5. Teflon

  1. Only 1 and 3

  2. Only 1, 3 and 5

  3. Only 2, 4 and 5

  4. Only 3 and 5

  5. Only 3, 4 and 5
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Chain growth polymerisation - In this type of polymerisation, the molecules of the same monomer or different monomers add together on a large scale to form a polymer. The monomers used are unsaturated compounds, e.g. alkenes, alkadienes and their derivatives. Examples are- LDPE, HDPE, Teflon, PAN, etc.

Multiple choice

Which of the following statements are false regarding Styrene–Butadiene Rubber (SBR)?

P. SBR is produced by the free-radical polymerization of styrene and butadiene. Q. Cold SBR is better suited to adhesive formulation than hot SBR. R. Tire treads made from emulsion SBR are superior to those from solution SBR. S. The ozone resistance of SBR is superior to that of natural rubber.

Select the correct answer using codes given below:

  1. P and Q

  2. P and R

  3. P and S

  4. Q and R

  5. Q and S
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Hot SBR is better suited to adhesive formulation than cold SBR. Hot SBR has a lower molecular weight and a broader molecular weight distribution than cold SBR. The lower molecular weight fraction provides quick stick, while the higher molecular weight fraction provides shear strength. On the other hand, narrow molecular weight distribution and higher trans structure of cold SBR make it less adaptable to adhesives.

Tire treads made from solution SBR are superior to those from emulsion SBR. Solution SBR has a higher molecular weight, narrower molecular weight distribution, and higher cis -1,4-polybutadiene content than emulsion SBR. These qualities reduce tread wear and enhance crack resistance of the tire.

Multiple choice

Which of the following statements is/are incorrect?

  1. Styrene–butadiene block copolymer belongs to the A-B-A type thermosetting polymer.
  2. Cellulose ethers are more sensitive to hydrolysis than cellulose.
  3. Tetramethylthioureadisulfide is used as accelerator in vulcanisation of rubber.

  1. Only 1

  2. 2 only

  3. Only 3

  4. Only 1 and 2

  5. Only 2 and 3
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Styrene–butadiene block copolymer belongs to the A-B-A type thermoplastic elastomer. The formation of cellulose ethers, unlike that of cellulose esters, is not reversible. Cellulose ethers are therefore less sensitive to hydrolysis than cellulose esters.

Multiple choice

Thermosetting plastics are soluble in ____.

  1. Ether

  2. Water

  3. Benzene

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

Thermosetting plastics are polymers that form cross-linked structures during curing, making them insoluble and infusible. They do not dissolve in common solvents like water, ether, or benzene.

Multiple choice

Bakelite do not melt on heating because such :

  1. polymers are attached by strong linear chains

  2. polymers are poor conductors of heat

  3. polymers are strong and inexpensive

  4. polymers are joined by strong cross links
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

It has cross linked structure and so it is hard to melt.