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16 Cards in this Set
- Front
- Back
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Define addition polymerisation
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The process in which unsaturated alkene monomers add on to growing polymer chains one at a time to form a very long saturated molecule chain.
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Define copolymerisation
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joining 2 different monomers during addition polymerisation
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Give 2 properties of elastomers
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-soft + springy
-can go back to original shape due to fewer cross-links |
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Give an example of an elastomer
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rubber
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Give 4 features of thermoplastics
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-have no cross-links
-intermolecular bonds much weaker than thermoset covalent cross-links -bonds can be broken through heat -can be moulded |
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Give an example of a thermoplastic
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PVC
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Give 2 features of thermosets
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-extensive, covalent cross-links
-stays in same shape when heated |
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Give an example of a thermoset
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bakelite
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Give 2 features of fibres
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-stronger thermoplastics that don't deform easily
-can easily be made into threads |
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Give an example of a fibre
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Nylon
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How does chain length affect polymer properties?
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longer chain --> stronger polymer
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How do side groups affect polymer properties?
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polar side groups (e.g. Cl) give stronger bonding between polymer groups
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How does branching affect polymer properties?
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straight unbranched polymers --> pack more closely --> stronger IM forces
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How does stereoregularity affect polymer properties?
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polymer chains can pack closer if side groups are oriented in certain way
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How does chain flexibility affect polymer properties?
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hydrocarbon chains very flexible; changes that make chain for rigid make a stronger polymer
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How does cross linking affect polymer properties?
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makes polymer stronger
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