Polymeric Materials

Question 1

What are polymers

Answer 1

– Very large molecules
– low density, light weight materials
– may be extremely flexible
– synthetic and natural materials

Question 2

What type of bond to polymers have

Answer 2

Covalent Bond
• electrons are shared between adjacent atoms, each contributing at least one electron
• shared electrons belong to both atoms
• directional bond means resulting
molecules have specific shapes

Question 3

Polymer Definition

Answer 3

A long 1D chain molecule of covalently bonded repeat units

Or a 3D network of covalently bonded repeat units

Question 4

Advantages of Polymer Characteristics

Answer 4

Easy Processing, High Ductility, Light Products, Thermal Insulators, Electrical Insulators, High Corrosion Resistance

Question 5

What atoms is a polymer chain made up of

Answer 5

Carbon and Hydrogen

Question 6

What is a monomer

Answer 6

Small, unreacted single molecule for polymer

Question 7

What is a mer

Answer 7

single repeat unit of a polymer

Polymer = entire polymer chain

Question 8

What is polymerisation

Answer 8

When monomer molecules react together to form polymer chains

Question 9

Degree of polymerisation formula??

Answer 9

n= (number of mer units) / (polymer molecule)

Question 10

Increasing a polymer chain length creates?

Answer 10

A stronger material, increased stiffness, higher melting point

Question 11

What is a linear chain polymer

Answer 11

a polymer consisting of a single continuous chain of repeat units

Question 12

What is a branched chain polymer

Answer 12

a polymer that includes side chains of repeat units connecting onto the main chain of repeat units

Question 13

What is a hyper branched chain polymer

Answer 13

a polymer consisting of a constitutional repeating unit including a branching groups

Question 14

What is a cross linked polymer

Answer 14

a polymer that includes interconnections between chains

Question 15

What is a net work polymer

Answer 15

a cross linked polymer that includes numerous interconnections between chains

Question 16

What are the three classes/groups of polymers

Answer 16

Thermoplastics, Thermosets, Elastomers/Rubbers

Question 17

What is the chain structure of a thermoplastic like?

Answer 17

Long chains with very limited or no cross-linking which behave in a plastic ductile manner

Question 18

Examples of Thermoplastic materials

Answer 18

Nylon, polyethylene, polystyrene, PVC

Question 19

What does POLY MER stand for?

Answer 19

Many Units

Question 20

What is the chain structure of a thermoset?

Answer 20

Highly cross-linked, 3D network structures

Question 21

Thermoset mechanical properties?

Answer 21

Birttle, decompose when heated

Question 22

Examples of Thermoset materials

Answer 22

urethane, epoxy, polyester,

and silicone

Question 23

Elastomers and rubbers chain structure

Answer 23

Light cross-linking, allowing the material to return to its original shape without plastic deformation

Question 24

What is a homopolymer

Answer 24

A polymer consisting of only one type of constitutional repeating unit

Question 25

What is a copolymer

Answer 25

A polymer consisting of two or more constitutional repeating units (A-B )

Question 26

What is a Polymer Crystal

Answer 26

Ordered atomic arrangements involving molecular chains

Polymers can be crystalline

Question 27

Can a polymer be completely Crystalline?

Answer 27

No

Question 28

Max percentage of polymer degree of crystallinity?

Answer 28

95% (HDPE)

Question 29

What two compositions make up a polymer structure diagram?

Answer 29

Amorphous regions & Crystalline regions

Question 30

affects of increasing the crystallinity of a polymer

Answer 30

increase the strength and rigidity of the polymer

Question 31

2+2=4, -1 =3

Answer 31

Quick Maths

Question 32

How can plastics be formed?

Answer 32

Injection moulding (thermoplastics and some thermoset)
Extrusion
Blow Moulding
Extrusion Blow Moulding
Injection Blow Moulding
Compression and transfer moulding