Polymers Flashcards
Alkanes
Saturated, fully bonded, no polarity, low reactivity, single bonds, stable, CnH2n+2
Alkenes
Unsaturated, double bonds, likely to bond and join with other monomers by opening the double bonds up, no methene, CnH2n
Isomer
Different forms of the same formula/chemical
Polymer
Made of many monomers joined together. It is a substance of high average molecular mass made up of small repeating units
Addition polymerisation
When small molecules join together with other molecules by opening up their double bonds
Poly(ethene)
Flexible, cheap, good insulators, stretchy, light. Used for plastic bottles, plastic bags, cling film, laminating paper
Poly(propene)
Flexible, tough. Used for buckets, bowls, crates, thermal underwear, ropes and carpets
Poly(chloroethene)
Can be made flexible or hard, tough, resistant to wear. Used for window frames, clothing, gutters and pipes
Poly(tetrafluroethene)
Tough, slippery, flame resistant, unreactive. Used for no-stick frying pans and stain coating
Properties of plastics
Non biodegradable, easy to colour, waterproof, strong, malleable, thermal and electrical insulator, non toxic
Why is it good to recycle
It is non-biodegradable, occupies too much space in landfills, releases toxic products and gases when combusted/incinerated (carbon dioxide, water, sulfur dioxide, nitrogen oxide, helps conserve resources, but it is expensive and difficult
Depolymerisation
The process of converting a polymer into a monomer or a mixture of monomers
Natural organic polymers
DNA - nucleotides
Protein - amino acids
Starch - glucose
Cornstarch polymers
Biodegradable and environmentally friendly. Made from vegetables high in starch such as potatoes, corn and maize. Used to replace oil based thermoplastics in packaging
Paper foam
Biodegradable, scratch resistant and mouldable. Made from starch based fibres and paper fibres. Used for shaped inserts for packaging
Potatopak
Can be composted, biodegradable. Made from potato starch. Used for biodegradable disposable trays, plates, bowls, cups and containers. Used for pig food or worm food when composted
Condensation polymerisation
Where water is eliminated
Esterification
Makes esters
Functional group
Atom or group of atoms responsible for the properties and reactions of an organic compound
Functional group of polyesters
C=O-O (made by condensation reaction)
Functional group of alcohols
-OH (hydroxyl)
CnH2+1OH
Functional group of carboxylic acids
COOH (carboxyl) double bonded oxygen
CnH2n+1COOH
Functional group of alkanes
Single bonds
Functional group of alkenes
Double bonds
Polyesters, what are they and how are they made?
Synthetic polymers made by condensation polymerisation which the smaller carboxylic acids and alcohol monomers join together to form a longer chain and water is eliminated. The reaction is sped up by using concentrated acids and heat
Beer made from
Barley, hops
Vodka made from
Potatoes
Wine made from
Grapes
Alcohol production
Sugar (carbohydrate) —-> (yeast) ethanol + carbon dioxide
Purpose of sugar in fermentation. Why must it be a glucose solution?
Nutrients for the yeast. 100% glucose makes pure ethanol
Purpose of airlock in fermentation
Must be anaerobic conditions for yeast to produce ethanol (they don’t produce lactic acid like humans)
Purpose of controlled temperature in fermentation
Must be 25°C as that is the optimum temperature for catalytic conditions (yeast are enzymes)
Alcohol reactions
Undergo complete combustion, can be oxidised to form carboxylic acids, react with metals to form hydrogen gas
Production of polyesters
Carboxylic acid + alcohol —> (under acidic conditions) polymers + water
Amide functional group
C=O-N-H
Bromine water experiment with alkanes
Alkanes are saturated and have single bonds. This means that they have no/low polarity and can’t open their bonds to join with the bromine. Therefore, the orange bromine water stays orange when combined with alkanes
Bromine water experiment with alkenes
Alkenes are unsaturated and have double bonds. This means that they have polarity, are unstable and are reactive. Their double bonds open up to join with the bromine in order to be stable and so the bromine water turns from orange to colourless.
H H
| |
H-C-C-H
| |
Br BrWhat is electronegativity?
The tendency of an atom to attract a shared pair of electrons towards itself
But-1ene
Count from carbon where the double bond is connected to (carbon on the left)
H H H H
\ | | |
C=C–C–C–H
/ | |
H H H
But-2ene
H H H
| | |
H–C–C=C–C–H
| | |
H H HFormation of poly(ethene)
The double bonds between the two carbon atoms open up in ethene (monomer now repeating unit). Ethene molecules join together by connecting to these opened up bonds to form poly(ethene) with single bonds by addition polymerisation.
Many monomers -pressure and catalyst-> polymer
How does the repeating unit differ from the monomer in poly(ethene)?
The monomer has double bonds whereas the repeating unit has single bonds that have already opened up and so more monomers are able to add on to make a polymer
General equation for any addition polymerisation
W X W X
\ / | |
C=C —> –(—C-C—)– n
/ \ | |
Y Z Y Z
monomer repeating unit
Naming polymers
- Name by counting the longest chain (MEPB), which is the one with the most carbons.
- Then give the functional group of this e.g. double bond means -ene or -anol
- Look for any side arms branching from it e.g. propyl and this goes before the forename
