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 is a set of elastomers?

  1. Dacron, nylon-66, synthetic rubber

  2. Neoprene, terylene, bakelite

  3. SBR, nitrile rubber, nylon-66

  4. Nylon-66, dacron, bakelite

  5. Buna-S, NBR, neoprene
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

Buna-S, NBR and neoprene: All are examples of elastomers.

Multiple choice

Which of the following compounds ingredients are used as blowing agents for polymers?

  1. Calcium carbonate
  2. Zinc carbonate
  3. 5-phenyltetrazole
  4. Azodicarbonamide

  1. Only 1 and 2

  2. Only 1 and 4

  3. Only 1, 2 and 3

  4. Only 2, 3 and 4

  5. All of these
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Yes, it is correct., as all are used as blowing agent for polymers. Zinc carbonate is an inorganic chemical blowing agent which decomposes at higher temperature than bicarbonates. 5-phenyltetrazole (5-PT) has been widely used as a blowing agent for foaming high temperature-processing polymers. The principal use of azodicarbonamide is in the production of foamed plastics as a blowing agent.

Multiple choice

Which of the following sets of polymers is biodegradable?

  1. Nylon 6, 6 and rayon

  2. Polystyrene and PHBV

  3. PVC and teflon

  4. PHBV and Nylon 2–nylon 6

  5. Nylon 2–nylon 6 and PVC
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Poly β-hydroxybutyrate – co- β -hydroxy valerate (PHBV) is a biodegradable polymer obtained by the copolymerisation of 3-hydroxybutanoic acid and 3 - hydroxypentanoic acid. Nylon 2–nylon 6 is an alternating polyamide copolymer of glycine (H2N–CH2–COOH) and amino caproic acid [H2N (CH2)5 COOH] and is biodegradable.

Multiple choice

Which of the following statements are not correct?

  1. Thermosetting plastics cannot be recycled.
  2. Elastic deformation in polymers is due to slippage of molecular chains.
  3. Low-density polyethylene is more crystalline than high-density polyethylene.
  4. Elastomers consist of hank-like polymer chains.

  1. 1 and 2

  2. 1 and 3

  3. 2 and 3

  4. 2 and 4

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

Elastic deformation in polymers is due to slight adjustment of molecular chains. High-density polyethylene is more crystalline than low-density polyethylene because it contains fewer branches.

Multiple choice

Which of the following is an example of semi-crystalline thermoplastics?

  1. Polyetherimide

  2. Polyether ether ketone

  3. Thermocole

  4. Lexan

  5. PVC
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Polyether ether ketone (PEEK) is a semicrystalline thermoplastic polymer with excellent mechanical and chemical resistance properties that are retained till high temperatures. Thus, this option is correct.

Multiple choice

Which of the following polymers has highest glass transition temperature (Tg)?

Glass Transition Temperature: The glass–liquid transition (or glass transition for short) is the reversible transition in amorphous materials from a hard and relatively brittle state into a molten or rubber-like state.

  1. Low-density polyethylene

  2. Polyvinyl chloride

  3. Polyhydroxybutyrate

  4. Polyethylene terephthalate

  5. Polytetrafluoroethylene
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

Glass transition temperature (Tg) of polytetrafluoroethylene (PTFE) is 115 oC.

Multiple choice

Which of the following are examples of dispersant?

  1. Citric acid ethyl ester
  2. Dibutyl sebacate
  3. Polyisobutylene
  4. n-Butyl benzyl phthalate

  1. 1 and 2

  2. 1, 2 and 4

  3. 2 and 3

  4. 2, 3 and 4

  5. 1, 2, 3 and 4
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

Citric acid ethyl ester is used as a plasticizer for polyvinylchloride and similar plastics. Dibutyl sebacate is a dibutyl ester of sebacic acid. Its main use is as a plasticizer in production of plastics such as cellulose acetate butyrate, cellulose acetate propionate, ethyl cellulose, polyvinyl butyral, polyvinyl chloride, polystyrene, and many synthetic rubbers and other plastics. Polybutene and polyisobutylene are liquid oligomers widely used as plasticizers for high-molecular weight polymers, such as polyethylene. n-Butyl benzyl phthalate is an ester of phthalic acid, benzyl alcohol and n-butanol. It is mostly used as a plasticizer for PVC.

Multiple choice

Match the following compounding ingredients in plastic technology with their respective functions:

 
Compounding
Ingredients functions
P. Nahcolite 1. Pigment
Q. Bis(2-ethylhexyl) phthalate 2. UV stabilizer
R. Titania 3. Blowing agent
S. Salol 4. Plasticizer

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

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

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

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

  5. P - 2, Q - 4, R - 1, S - 3
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Nahcolite (sodium bicarbonate) is commonly used as a blowing agent in the manufacture of rigid foams which are chiefly polystyrene polyurethane, epoxy and polyvinyl chloride. Dioctyl phthalate (Bis(2-ethylhexyl) phthalate) is the most common of the class of phthalates which are used as plasticizers. Titania (titanium dioxide) is the most important white pigment used in the polymer industry. Salol (phenyl salicylate) is used as UV stabilizer for commercial polymers and sun tanning lotions.

Multiple choice

Which of the following statements about Lexan are not correct?

  1. It is manufactured by the reaction 4, 4'-(propane-2, 2-diyl)diphenol (BPA) with carbonyl dichloride.
  2. It belongs to the group of linear thermoplastic polyesters.
  3. It is highly opaque.
  4. It has a glass transition temperature of about 200°C.

  1. 1 and 2

  2. 1 and 3

  3. 1 and 4

  4. 2 and 3

  5. 3 and 4
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

Polycarbonate (Lexan) is highly transparent to visible light, with better light transmission than many kinds of glass. Polycarbonate (Lexan) has a glass transition temperature of about 147°C, so it softens gradually above this point and flows above about 155°C.

Multiple choice

Which of the following are examples of amorphous thermoplastics?

  1. Poly(4-methyl-1-pentene)
  2. Polyphenylene oxide
  3. Polyetherimide
  4. Polyphenylene sulfide
  5. Polyamide-imide
  6. Poly(propene)

  1. 1, 2 and 5

  2. 2, 3 and 5

  3. 2, 4 and 6

  4. 3, 5 and 6

  5. 4, 5 and 6
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Polyphenylene oxide is an amorphous standard thermoplastic polymer. Polyetherimide (PEI) is an amorphous thermoplastic with high mechanical strength and rigidity. Polyamide-imide (PAI) are amorphous thermoplastic high performance polymers characterized by high thermal stability.

Multiple choice

Which of the following is not a characteristic of vulcanised rubber?

  1. It does not melt upon heating.

  2. It is resistant to chemical attack.

  3. It is an insoluble thermosetting polymer.

  4. It possesses weak covalent bonds.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

 When rubber is vulcanised, it becomes cross-linked. This linking of stronger bonds makes vulcanised rubber over 10 times stronger than natural rubber.