Free Practice Quiz Question List

08 Polymers Online Quiz Questions

Use this free practice quiz with 20 questions to review 08 Polymers, test your knowledge, and prepare for your next test or exam.

20 questions

True or false

1 point

A thermoplastic part can generally be softened by heating and solidified again by cooling, although repeated heating may eventually degrade it. Is this statement true or false?

A
True
B
False

Choose one

1 point

A polymer has many side chains attached to its main chains. Which structural effect is most likely compared with a similar mostly unbranched polymer?

A
The chains can pack more closely because the side chains align them.
B
The side chains interfere with close packing and can change density and flexibility.
C
The polymer becomes a three-dimensional network of covalent bridges.
D
The side chains ensure that the polymer is wholly crystalline.

Choose one

1 point

A manufacturer increases the crystalline fraction of a semicrystalline polymer. Which set of effects is most consistent with that change?

A
It generally increases clarity and toughness while reducing stiffness.
B
It has no meaningful effect on strength, heat resistance, or clarity.
C
It generally increases stiffness and strength, but can reduce clarity and sometimes toughness.
D
It makes the polymer wholly crystalline and prevents it from responding to temperature.

Choose one

1 point

A semicrystalline polymer is heated above its glass-transition temperature but remains below its melting temperature. What change should occur?

A
The amorphous regions become more flexible and rubbery, while the crystalline regions have not yet reached their melting transition.
B
The amorphous regions become more glassy, while the crystalline regions necessarily melt.
C
The polymer becomes a permanent cross-linked network.
D
All regions become wholly crystalline.

Choose one

1 point

A polymer feels stiff during a quick impact but slowly changes shape under a constant load. Which explanation best accounts for this behavior?

A
It must remain equally stiff regardless of how long the load is applied.
B
It can deform only if its crystalline regions melt.
C
It immediately becomes a thermoset when a load is sustained.
D
It may gradually deform over time because its chains can move relative to one another.

Choose one

1 point

A factory needs to produce large quantities of complex solid plastic parts. Which process injects softened polymer into a closed mold, then cools and ejects the parts?

A
Extrusion
B
Blow molding
C
Injection molding
D
Thermoforming

Choose one

1 point

A cured epoxy component must retain its shape during service at elevated temperature. Which description best explains why reheating it will not allow it to be reshaped like a thermoplastic?

A
It softens reversibly and can be reshaped by ordinary reheating.
B
Its cured cross-linked network does not melt and flow like a thermoplastic; further heating may damage it.
C
Its chains separate into monomers whenever it is cooled.
D
It becomes easier to reshape each time it is heated.

Choose one

1 point

A polymer producer increases the molecular weight of a material to improve its mechanical performance. Which processing trade-off should the producer anticipate?

A
It often improves toughness and strength but makes the molten polymer more viscous and harder to process.
B
It always reduces toughness and strength while making the molten polymer less viscous.
C
It affects only the color of the polymer, not its processing behavior.
D
It makes all chains in the sample have exactly the same molecular weight.

Written response

1 point

What structural feature consists of covalent bridges connecting neighboring polymer chains?

Written response

1 point

A sample contains 2 chains with molecular weight 1,000 g/mol and 2 chains with molecular weight 3,000 g/mol. What is its number-average molecular weight, $M_n$ ?

Choose one

1 point

Which thermoplastic process continuously pushes softened polymer through a shaped die to produce items such as pipe, sheet, or film?

A
Extrusion
B
Injection molding
C
Blow molding
D
Thermoforming

Choose all

1 point

Which statements about polymer structure are supported? Select all correct answers.

A
Tacticity describes the arrangement of side groups along a polymer chain.
B
The sequence of different monomers in a copolymer can affect how regularly chains pack.
C
Tacticity and copolymer sequence are structural details that can influence polymer properties.
D
Tacticity is the name for the process used to push softened polymer through a die.

Choose all

1 point

A team is choosing processing conditions for a polymer part and wants to reduce the risk of defects or unwanted dimensional changes. Which factors should it consider? Select all correct answers.

A
Whether the material can flow or conform to the intended shape without damage
B
The color of the manufacturing equipment
C
Temperature and pressure during processing
D
Flow and cooling or curing conditions

True or false

1 point

In extrusion, softened polymer is pushed continuously through a shaped die.

A
True
B
False

True or false

1 point

Blow molding forms a hollow product by drawing or pressing a heated plastic sheet over a mold.

A
True
B
False

Written response

1 point

What technical term describes the arrangement of side groups along a polymer chain? Enter the term.

Written response

1 point

What are the repeating chemical units from which a polymer is built called? Enter the plural term.

Fill in the blank

1 point

To make a hollow plastic bottle, air expands a softened polymer tube against a mold in a process called .

Fill in the blank

1 point

A process that draws or presses a heated plastic sheet over a mold, often using vacuum or pressure, is called .

Open ended

1 point

A manufacturer plans to make both hollow plastic bottles and shallow plastic trays from sheet material. Which process would you recommend for each product, and how does the way each process shapes the polymer make it suitable?