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Polymer revolution
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- 1What is a polymer?A long molecule made up from lots of small molcules called monomers
- 2What does it mean if there are A-A-A polymers?All the monomers in the molecule are the same (addition polmers)
- 3What does it mean if there are A-B-A-B polymers?There are 2 or more different monomers in the chain (copolymers)
- 4What is a plastic?Plastics are polymers that at some stage of their manufacture are capable of flowing
- 5What is a thermoplastic?A plastic that can repeatedly soften on heating and harden on cooling eg PVC
- 6What are thermosetting plastics?Plastics that form crosslinks between their chains
- 7What are elastomers?Soft and springy plastics that have fewer crosslinks eg rubber
- 8What are fibres?Strong thermoplastics used for clothes and don't deform easily eg nylon
- 9How was polyethene discovered?Polyethene was discovered by accident - they found that they had to control the process more to repeat this and that the leak that happened by accident added a small amount of oxygen
- 10What are the properties of polyethene?Polyethene is tough and durable
- excellent electrical insulating properties
- not affected by weather/water
- no tendency to absorb electrical signals
- burns well and tends not to react with acids/alkalis
- softens and melts over a temperature range
- behaves like an alkane - 11What is polyethene used for?It was originally used for a telephone cable but now it is used in washing up bowls, carrier bags, bottles and sandwich bags
- 12What is LDPE?LDPE is early polyethene
- it is branched so the chains don't fit together in an organised way which means it takes up lots of room, causing it to be low density
- the open structure lowers its strength - 13What is HDPE?HDPE is a crystalline structure to give the polymer high density and strengh eg in water tanks
- it can be moulded into complicated shapes but it's not as easily deformed as LDPE
- the ability to retain shape during heating means it can be heat sterilised for hospital equipment - 14How was HDPE discovered?Ziegler was studying catalytic effects of organometallic compounds and found that adding titanium compounds to an impurity led to easy production of long chain polymers with little branching and packed close together
- 15What are stereo regular polymers?These are polymers with a repeating pattern
- 16What does amorphous mean?Amorphous means there is an irregular pattern, meaning it is not crystalline
- 17What does crystalline mean?There is a regular repeating pattern with polymers packed closely together, making it strong and rigid
- 18How is polyethenol made?Methanol reacts with poly(ethenyl ethanoate) and some of the ester groups on the side chains are converted into O-H groups
- 19What is polyethenol used for?This is used in dissolving plastics for things like hospital laundry bags or washing tablets
- the solubility depends on the number of O-H groups - 20How was PTFE discovered?When wanting to use tetrafluroethane from a stored cylinder a white waxy solid was discovered
- 21What are the properties of PTFE?- it is a good electrical insulator
- anti stick properties
- resistant to chemical attack
- can be stretched - 22What is gore-tex?PTFE is stretched to form pores that allow water vapour but not liquid to pass through
- gore tex is an oil hating polymer that stops oil from blocking the pores of PTFE to preserve water proofing properties - 23What is ETFE?Ethene and tetrafluroethane used in the domes of the eden project due to high transparency, resistance to intense radiation and waterproofing
- 24What is neoprene?Neoprene is an elastomer used in wetsuits, phone cases and car components
- it is resistant to light, heat and chemical attack - 25What does isotactic mean?Same configuration at regularly spaced positions along the chain eg PVC
- 26What does atactic mean?Completely irregular and random chains
- it forms a non crystalline structure/amorphous - 27What does syndiotactic mean?Still regular chains but more complicated eg every 5th carbon rather than every other
- it's still quite crystalline - 28What are alkenes?Alkenes are hydrocarbons with at least one carbon double covalent bond, this makes the bond angle 120 degrees
- 29How can you test for a double bond?The solution goes colourless to form dibromoalkane
- 30What is an electrophile?Electron pair receptors that are attracted to negatively charged regions
- 31Describe the process of the electrophillic addition of bromine- the double bond repels the bromine causing it to become polarised
- the electron density is unequally distributed
- the bromine nearest the alkene becomes slightly positively charged
- it gives up the bonding electrons to the other Br and bonds to the carbon
- the carbon is positively charged and is called a carbocation
- the other Br bonds with the carbon - 32What is produced when you react an alkene with waterUnder the presence of a sulphuric acid catalyst alcohols are produced
- steam and a phosphoric acid catalyst produces ethanol - 33Describe hydrogen bondingMuch stronger than other intermolecular bonds
- there is a large dipole between a small hydrogen and an electronegative atom
- there needs to be a lone pair on the electronegative atom - 34What are the properties of compounds with hydrogen bondingThey have higher boiling points
- polymers can dissolve due to their ability to form hydrogen bonds - 35What is the primary structure of an alcohol?The OH is attached to the first alkyl group or 1 alkyl group
- 36What is the secondary alcohol?The OH is attached to 2 alkyl groups
- 37What is the tertiary structure of an alcohol?The OH is attached to 3 alkyl groups and no hydrogens
- 38What is the process of oxidising alcohols?Acidified potassium dichromate reduces the ion to green
- a carbonyl group is added (oxygen and carbon)
- we heat it under reflux to stop is from losing volatile components and it contains anti numbing granules to make boiling smoother - 39What is the products of oxidation of alcohols?If it is a primary alcohol then an aldehyde will be produced, this can be oxidised further into a carboxylic acid
- if it is a secondary alcohol then a ketone is produced
- tertiary alcohols don't undergo oxidation as they aren't attached to any hydrogen atoms - 40What is dehydration of alcohols?This forms alkenes by passing over a hot catalyst of aluminium oxide at 300 degrees and then reflux with concentrated sulphuric acid at 170 degrees
- 41What is polystyrene and poly(chloroethene) used for?Poly(chloroethene) is durable and flexible and so used for water pipes and electric wires
Polystyrene is light and a good insulator so it makes disposable cups and crash helmets - 42What is E/Z isomerism?A type of stereoisomerism with the same order but arranged differently in space
- 43What is trans?Trans refers to E isomerism
- this is when the same groups are across the double bond from eachother - 44What is cis?Cis refers to z isomerism
- this is when the two groups are on the same side of the double bond - 45What will the properties of E/Z isomerism be like?They will have the same chemical properties and react with bromine water the same but they will have different physical properties because of the way they're arranged eg E has a slightly higher melting point as the molecule can get closer
- 46What happens when molecules absorb IR radiation?Each bond absorbs energy at a different frequency causing it to vibrate more vigorously
- 47What is the fingerprint region?The fingerprint region is below 1500cm where each molecule has a specific absorption pattern
- 48How do simple diatomic molecules vibrate?They only vibrate in one way - by stretching
Energy to excite the vibration depends on the strength of the bond
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- Fichas sobre Polymer revolution, creado por Adelle Cragg el 01/06/2015.
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- Adelle Cragg
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