Topic 7- Polymers
No description yet. This curated deck is ready for daily study.
Card preview (24)
What is the Eden Project made from?
Ethylene tetrafluoro ethylene (ETFE)
Does ETFE have high or low density?
Low density
Important feature of ETFE?
Optically transparent.
Why are polymers used a lot for buildings?
Cheap and easy to produce.
What are polymers and plastics?
Polymers are materials with large macro-molecules, of which plastics is just on group.
What 6 useful properties do plastics have that mean they are widely used?
• Good thermal/electrical insulation. • Low density/ • Easy to manufacture and low cost. • Useful as adhesives (including composites). • Good transparency. • Durable
When do plastics have poor durability?
Under UV light.
What is the main characteristic of thermoplastic polymers?
Melt when heated so can form different shapes.
What is the main characteristic of elastomers?
Very high strain to failure (carbon chains are curled up so will stretch out).
What is the main characteristic of thermosets?
Crosslinks mean they will not melt when reheated, so will burn.
What is the main characteristic of Polysiloxanes?
No carbon backbone - alternating string of oxygen and silicon atoms.
What is the plastic most commonly used in building and construction?
PVC
What is the main component in polymers?
Carbon
What are the three organic elements in polymers? What is the fourth (non-organic?) element?
Carbon (C), Hydrogen (H), Oxygen (O). Silicon (Si)
How big are polymer molecules in comparison to hydrocarbons?
Gigantic (macro-molecules).
What is the bonding in a polymer?
Atoms bound by covalent bonds to form long and flexible chains, secondary bonds between chains.
Are polymers crystalline or amorphous?
Amorphous or partially crystalline.
What is the name of the repeated unit in a polymer chain?
‘mer’ unit.
What does polymer mean?
Many parts
What is polymerisation?
Process of reacting polymer monomer molecules together in a chemical reaction to form three-dimensional networks or polymer chains.
What is one mer of polyethylene (PE)?
H-C-H H-C-H
What is one mer of polyvinyl chloride (PVC)?
H-C-H H-C-Cl
What is one mer of polypropylene (PP)?
H-C-H H-C-CH3
What are the two determining characteristics of polymers?
Low stiffness and low melting points.