Chemistry

Polymers and Plastics

1,227 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 man made materials environmental impact: plastics plastic plastic plastic waste garbage in, garbage out

Statement: The articles made of thermoplastics can be recycled whereas the articles made of thermosetting plastics cannot be recycled.


State whether the given statement is true or false.

  1. True

  2. False
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
The intermolecular forces in thermoplastics are weaker while the intermolecular forces in thermosetting plastics are stronger. The thermosetting plastics cannot be moulded on heating. Thus the articles made of thermoplastics can be recycled whereas the articles made of thermosetting plastics cannot be recycled.

Hence, the given statement is $\text{true}$
Multiple choice chemistry man made materials environmental impact: plastics plastic plastic plastic waste garbage in, garbage out

Thermoplastics are:

  1. linear polymers.

  2. soften or melt on heating

  3. molten polymer can be moulded in desired shape.

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

Thermoplastics are linear polymers. They are also known as thermosoftening plastics because they become malleable when heated. Although they are pliable above a certain heat threshold, they return to a solid once they have been sufficiently cooled. For this reason, thermoplastics are put to unique uses in a number of manufacturing and engineering industries.

Apart from their primary characteristics, thermoplastics vary slightly in usage and properties. For example, polystyrene is a hard, water-resistant thermoplastic, according to BBC. This makes it an excellent choice for creating toy models and for packaging that will not be exposed to extreme heat sources in transit. Polymethyl methacrylate is also a stiff thermoplastic, but it is also an electrical insulator and can be polished well, so it is often used in vehicle windows and light covers.

Multiple choice chemistry man made materials environmental impact: plastics plastic plastic plastic waste garbage in, garbage out

Which of the following is used to make disposable cups?

  1. Low density polyethylene

  2. Polypropylene

  3. Polystyrene

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

Disposable cups are made up of thermocol. It is a synthetic petroleum product which is made by restructuring of the chemical bonding of the polystyrene, to develop a stretch polystyrene. In this process, thermoplastic granules are expanded through the application of steam and air. The expanded granules become large and light in weight.

Multiple choice chemistry man made materials environmental impact: plastics plastic plastic plastic waste garbage in, garbage out

Thermosetting plastics can be remoulded on gentle heating.

  1. True

  2. False
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Thermosetting plastics: Which on heating becomes infusible these cannot be reused.Ex- Bakelite,urea formaldehyde resin.

Thermoplastic plastics: These become soft on heating and hard on cooling.
Ex.polythere,polystyrene.
Thermoplastic plastics can be remoulded.

Multiple choice chemistry man made materials environmental impact: plastics plastic plastic plastic waste garbage in, garbage out

Which of the following is considered the first thermoplastic?

  1. PVC

  2. Polystyrene

  3. Melamine

  4. Celluloid
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Celluloid, which is considered the first thermoplastic, made its appearance in the mid- 1800 s and reigned in the industry for approximately 100 years. During its peak production, it was used as a substitute for ivory. Today, it is used to make guitar picks.

Multiple choice chemistry man made materials environmental impact: plastics plastic plastic plastic waste garbage in, garbage out

Which of the following is a thermosetting process?

  1. Vulcanization of rubber

  2. Polythene extrusion

  3. Injection molding of PVC

  4. None of above
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Vulcanization is a chemical process for converting natural rubber or related polymers into more durable materials via the addition of sulphur or other equivalent curatives or accelerators. Cross-linking introduced by vulcanization prevents the polymer chains from moving independently. As a result, when stress is applied the vulcanized rubber deforms, but upon release of the stress it reverts to its original shape.

Multiple choice chemistry man made materials environmental impact: plastics plastic plastic plastic waste garbage in, garbage out

State true or false.


Nylon is a thermosetting plastic.

  1. True

  2. False
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
Thermoplastics are the polymers which loses their shape on heating and regain their shape on cooling.
Examples: Nylon, PVC, polystyrene, etc.
On the opposite of that Thermosetting doesn't regain its shape after heating.
Nylon is a thermoplastic polymer. Hence the given statement is false.
Multiple choice chemistry man made materials environmental impact: plastics plastic plastic plastic waste garbage in, garbage out

Which of the following is/are reasons of using plastics?
1.They are transparent.
2. They are cheap.
3. They can be moulded into diffrent shapes.

  1. (1) only

  2. (2) only

  3. (1) and (3) only

  4. (2) and (3) only
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation
All three are correct. But the reason for their vast use is the less expenditure and re-usability. 
With the increased knowledge of plastics and the improved capabilities of machining equipment, the industry is now capable of producing plastic components to the same exacting standards as metallic components.
Plastics are cheaper than metals.  They are transparent and elastic material that could be molded when heated. Plastics are easy to reuse as they can be molded into different shapes can be designed for resist impact and dents, making it durable, strong, and stable.


Multiple choice chemistry man made materials environmental impact: plastics plastic plastic plastic waste garbage in, garbage out

Which is NOT the general characteristics of plastics?

  1. Good electrical insulators

  2. Acceptable acoustic insulation

  3. Resistant to corrosion and many chemical factors

  4. Have a high production cost
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation
The properties and characteristics of most plastics (though not always fulfilled in certain special plastics) are these:
Easy to work and shape,
Have a low production cost,
Possess low density,
Tend to be waterproof,
Good electrical insulators,
Acceptable acoustic insulation,
Good thermal insulation, but most can not withstand very high temperatures,
Resistant to corrosion and many chemical factors;

Multiple choice chemistry man made materials environmental impact: plastics plastic plastic plastic waste garbage in, garbage out

Which of the following is thermosetting polymer?

  1. Nylon

  2. Sealing wax

  3. Polysiloxanes

  4. Both B and C
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Thermosetting polymers: These polymers are cross linked or heavily branched molecules, which on heating undergo extensive cross linking in moulds and again become infusible. These cannot be reused. Some common examples are polysiloxanes, bakelite, urea- formaldehyde resins, etc.