Polymers 3.3.12 Flashcards
what are the 3 main types of condensation polymers
- Polypeptides
- Polyamides
- Polyesters
what is condensation polymerisation
2 different monomers with at least 2 functional groups react together .
When they react a link is made , and water is eliminated
where are polypeptides found
In proteins
how are polyamides formed
By reacting diamines and dicarboxylic acids
how are polyesters formed
By reacting a diol and a dicarboxylic acid together
what link is formed when polyamides are formed
amide links
why are dicarboxylic acids and diamines used to form polyamide
They have functional groups either side which allows a chain to be formed
what is kevlar
a polyamide that is used in bulletproof vests , car tyres and some sports equipment as it is light weight but strong
what is kevlar made from
Benzene - 1,4 - dicarboxylic acid and 1,4 - diaminobenzene
what is Nylon 6,6
A polyamide that is used in ropes , carpets , clothing and parachute fabric
what are the 2 examples of polyamides
nylon 6,6 and Kevlar
what is nylon 6,6 made from
Hexanedioic acid and 1,6-diaminohexane
what is the part inside the brackets of a polymer called and what are some rules
The repeating unit .
Do not draw the H2O from both the molecules .
Dont draw the Hydrogens on the ends
what links are formed when polyesters are formed
ester links
what is an example of a polyester
terylene
what is terylene
polyester that is used in plastic drink bottles , sheeting and clothes.
acronym = PET
what is terylene made from
benzene - 1,4- dicarboxylic acid and ethane -1,2-diol
what is hydrolysis of condensation polymers
Condensation polymers can be hydrolysed to produce the original monomers . It’s just the reverse of polymerisation
how do you determine the monomer units produced
-Break the bond in the middle of the amide or ester link of the repeat unit
- Add OH and H to each of the monomer units
what causes the polar bonds in condensation polymers
Caused by C-O and C-N bonds that exist in the polymers
why are condensation polymers stronger than addition polymers
- They’re more rigid and stronger
- Hydrogen bonds exist between the polymer chains as well as dipole - dipole and Van de waals forces
what are synthetic polymers
Made from monomer units and used to make a range of items from plastic bottles , digital technology to non- stick coatings on pans
what are properties of condensation polymers
- Polar and hence susceptible to attack from nucleophiles
- They are biodegradable and broken down by hydrolysis slowly
what are properties of addition polymers
- They’re saturated molecules
- Normally non polar and hence are unreactive
- They are good when used in foods as they don’t react
- However they don’t degrade well in landfill
when is using landfills useful for disposing plastics
• when plastics are too difficult to recycle
• are too difficult to separate from other materials
• There is not enough plastic to extract to make it economically viable
what are the 3 ways of disposing plastics
- Using landfills
- Incineration
- Recycling
what’s are disadvantages of using landfills to dispose plastic
•When waste decomposes in landfill it produces methane which is a greenhouse gas .
• There is also a risk of water contamination from waste leaching
• Not sustainable as large amounts of land is needed
• Becoming increasingly expensive to use land for waste disposal
when is incineration used in disposal of plastics
• if plastics can’t be recycled
• the energy from burning it can be used to generate electricity
what are disadvantages of using incineration when disposing plastics
- Burning plastics can release toxic fumes so these need to be monitored. Particularly chlorine based plastics e.g. PVC which produce harmful HCl gas when burned
what can be used to neutralise acidic gases produced in incineration of disposing plastics
Flue gas scrubbers.
They work by firing a base at the flue gases
what’s the use of recycling plastics
-most plastics are made from crude oil which is a non-renewable resource
- Recycling means reducing dependency on crude oil for making plastics , saving precious resources
what’s another way to allow new production of plastics and other chemicals
Other plastics can be cracked into monomers to be used as an organic feedstock
what are the disadvantages of recycling plastics
- Plastics can be contaminated with other materials when being recycled
- It is difficult to recycle plastics due to the wide variety of different plastics
- It is difficult to remake the original plastic from recycled material
- Sorting and processing plastics to be recycled is expensive compared with incineration
what are the advantages of recycling plastics
- It is cheaper to recycle plastics than make them from scratch
- Less carbon dioxide is produced recycling plastics than incinerating them
- Recycling reduces the reliance on landfill
- Recycling preserves non renewable raw materials such as crude oil
EQ : Explain why polyesters are biodegradable but polyalkenes are not biodegradable (2)
- polyesters are polar so susceptible to be attacked by nucleophiles
- polyalkenes are non polar
EQ : which polymer has hydrogen bonding between the polymer chains (1)
Kevlar
Eq : Name the type of reaction that occurred between the polyester and the aq NaOH . Explain why the aq NaOH reacted with the polyester (3)
Hydrolysis
Delta positive C in polyester reacts with OH-
