QUIZ 3 Flashcards

1
Q

Plastics, commonly used in commercial applications, are derived from

A

polymers or prepolymers.

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2
Q

while plastics are a type of polymer, ________polymers are plastics

A

not all

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3
Q

pure material which is usually the umbrella term for materials which have long chain-like molecules.

A

Polymer

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4
Q

made up of large molecules consisting of structural units called monomers, which
gives plastics their distinctive properties and versatility

A

polymers

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5
Q

key mechanism behind
plastics production

A

polymerization

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6
Q

There are different types of polymerization but in plastics, ____________________
polymerizations are usually applied.

A

addition and condensation

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7
Q

the monomer units containing double or triple bonds or unsaturated
molecules, are added successively to form a linear polymer chain.

A

addition polymerization

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8
Q

An example of a plastic that conforms to addition polymerization is

A

polyethylene

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9
Q

involves formation of polymers through the elimination
of small molecules such as water, as monomers react

A

condensation polymerization

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10
Q

An example
of condensation polymerization is the synthesis of

A

polyester Dacron and polyamide Nylon 66.

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11
Q

e backbone of modern plastics

A

polymers

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12
Q

The molecular weight and chain length of polymers directly impacts the

A

strength and durability of plastics

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13
Q

Shorter chain length often translates to __________ polymer,

A

weaker

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14
Q

the presence of side chains attached to
the main polymer chain

A

branching

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15
Q

Branching influences

A

flexibility and elasticity

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16
Q

______ polymers are rarely used on their own

A

pure

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17
Q

usually incorporated to polymers to further
enhance the properties of the resulting plastics, allowing for customization to meet specific requirements.

A

Additives

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18
Q

Some of the common additives used in the plastic industry are

A

Antioxidants
Antistatic agents
Blowing agents
Fillers
Flame retardants
Heat stabilizers
Pigments
Plasticizers
UV Stabilizers

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19
Q

function as a protective agent for polymers during thermal processing to
avoid product deterioration in short and long-term use at elevated temperatures.

A

heat stabilizers

20
Q

utilized to impart colors to plastics.

A

Pigments and dyes

21
Q

These are added to plastics to aid flow and processing.

A

plasticizers

22
Q

They are low molecular weight
materials that alter the properties and forming characteristics of the plastic

A

plasticizers

23
Q

These are used in plastics to inhibit both oxidative degradation and thermal oxidation.

A

antioxidants

24
Q

makes it possible for plastic
surfaces to attract moisture from air which improves its surface conductivity and reduces thertm
chances of a spark or discharge.

A

antistatic agents

25
Q

These are added to plastics to make foam or cellular structures in the final product.

A

blowing agents

26
Q

are solid particles that are incorporated
into plastics to enhance properties and reduce costs

A

Fillers (inorganic)

27
Q

enable large volumes of plastic using a small
amount of polymer resin

A

extender

28
Q

frequently used as extenders.

A

Low-cost solids like calcium carbonate, silica, and clay

29
Q

Reduce the likelihood that combustion will occur or spread.

A

Flame retardants

30
Q

Examples of flame retardants

A

chlorine, nitrogen, bromine, phosphorus, or metallic salt

31
Q

long chain-like molecules are kept together by weak van der Waals forces

A

thermoplastics

32
Q

typically measured using the
molecular weight and molecular weight distribution of the polymer

A

chain lengths

33
Q

thermoplastic materials with the same chemical formula to
exist in distinct molecular configurations, resulting in extremely diverse characteristics

A

isomerism

34
Q

the most commonly used thermoplastic

A

polyethylene

35
Q

When it takes the form of a mostly linear chain,
the chains can be packed closely together, and the material is known as _____________

A

HDPE

36
Q

Other common commercial thermoplastics

A

(PVC), polystyrene, nylon, cellulose acetate, polycarbonate, polyethylene terephthalate (PET),
polymethyl methacrylate, polylactic acid (PLA), and polypropylene

37
Q

A key distinction among thermoplastic materials

A

amorphous or crystalline

38
Q

Some polymers,
such as polyethylene and nylon, can acquire high levels of crystallinity, however they are perhaps
better classified as

A

partially crystalline or semi-crystalline

39
Q

Other plastics, including acrylic and
polystyrene, are invariably

A

amorphous

40
Q

the mechanical qualities of the molding are highly
dependent on whether or not the plastic is

A

crystalline

41
Q

In general, plastics have a higher density when

A

crystallized

42
Q

Properties of amorphous polymers

A

Broad softening range
Usually transparent
Low shrinkage
Low chemical resistance
Poor fatigue and wear resistance

43
Q

Properties of crystalline polymers

A

Sharp melting point
Usually opaque
High shrinkage
High chemical resistance
Good fatigue and wear resistance

44
Q

The most common type of plastic is called

A

commodity plastics

45
Q

utilized in
huge quantities in a variety of applications

A

commodity plastics

46
Q

Commodity plastics are mostly used in

A

packaging, toys, clothes, transportation,
and domestic products

47
Q
A