Polymers Flashcards
1
Q
What are the three types of polymers?
A
- Natural
- Synthetic
- Semi-synthetic
2
Q
What are some examples of natural polymers?
A
- Proteins
- Polysaccharides
- Resins/gums
3
Q
What are some examples of synthetic polymers?
A
- Plastics
- Elastomers
- Rubber
4
Q
What is a polymer?
A
- long chain molecule
- constructed from many monomers that are covalently bonded together
- can be linear, branched, cross-linked or colloidal
5
Q
What is a homopolymer?
A
Comprised of all the same monomers
6
Q
What is a co-polymer?
A
Made up of different monomers
7
Q
How do polymers end?
A
- there are end groups
- the nature of end groups allows method of synethsis to be analysed
- it is possible for there to be no end groups = rings
- useful for identifying a material
- ratio of end groups to in-chain groups allows measuring of polymer length
- reactive end groups allow further modification to control properties or add additional functionality
8
Q
Why are end groups useful for identifying a material?
A
- type of end group is unique and will give a unique signature
- ususally more reactive so can give a unique signature
9
Q
What are the 3 main types of polymer when classed by bulk properties?
A
- Thermoset
- Thermoplastic
- Elastomer
10
Q
What are the properties of thermoset polymers?
A
- burns when heated
- irreversibly hardened once shaped
- generally inflexible
- chemical process called curing required
11
Q
Examples of thermoset polymers
A
- epoxy resins
- silicones
- polyurethanes
12
Q
What are the properties of thermoplastic polymers?
A
- melts when heated
- can be remelted and reshaped
- generally more flexible
- no chemical curing required
13
Q
Examples of thermoplastic polymers
A
- polystyrene
- nylon
- polycarbonate
14
Q
What are the properties of elastomer polymers?
A
- can be thermoplastic or thermoset
- has viscosity (can flow) and eslasticity (return to orignial shape)
15
Q
Examples of elastomer polymers
A
- rubbers