Polymers Flashcards
When do addition polymers form?
When unsaturated monomors react
The monomers have C=C
Give an example of an addition polymer:
Poly(alkenes)
What makes poly(alkenes) non-biodegradeable?
Because they are chemically inert due to the strong C-C and C-H bonds and the non-polar nature of the bonds.
The non-polar bonds aren’t susceptible to attack from nucleophiles such as water so cannot be hydrolysed and thus are non-biodegradeable
What two linkages are involved in condensation polymers and what are the two most common types of condensation polymers?
Ester linkages and Amide linkages
Polyesters and Polyamides
What happens in condensation polymerisation?
Two different monomers that add together and a small molecule is usually given off as a side product e.g. H2O or HCl
Give 2 equations to show the formation of a poly(ester)?
dicarboxylic acid + diol –> poly(ester) + water
diacylchloride + diol –> poly(ester) + HCl
Give 2 equations to show the formation of a poly(amide)?
dicarboxylic acid + diamine –> poly(amide) + water
diacyl chloride + diamine –> poly(amide) + HCl
How are condensation polymers formed? Give three ways:
Dicarboxylic acid + diamine
Dicarboxylic acid + diol
Amino acids
What is Kevlar?
A polyamide
What two molecules is Kevlar made from?
benzene-1,4-dicarboxylic acid & 1,4-diaminobenzene
What is nylon 6,6?
A polyamide
What two molecules form Nylon 6,6?
Hexanedioic acid & 1,6-diaminohexane
What are the three types of condensation polymer?
Polyamide, polyester, polypeptide
Give two examples of polyamides?
Kevlar + Nylon 6,6
What two molecules are needed to make a polyamide?
Dicarboxylic acid, diamine
Dicarboxylic acid + diamine –>
polyamide + 2nH20
Where do the two molecules of water come from during the formation of a polyamide?
In order to form the repeating unit, one molecule is lost so the amide linkage can form and the other molecule is lost so that the repeating unit can join to other repeating units.
What is kevlar used in?
Bulletproof vest, sports equipment, car tyres
What is nylon 6,6 used in?
parachute fabric, ropes, clothing, carpets
Give an example of a polyester?
Terylene
What is terylene used in?
Plastic drinks bottles, sheeting and clothes
What is the acronym of terylene?
PET
What is terylene made from?
benzene-1,4-dicarboxylic acid and ethane-1,2-diol
Why are condensation polymers stronger than addition polymers?
Because of the polar C-N and C=O bonds, hydrogen bonds exist between the polymer chains, as well as dipole-dipole and VDW forces.
Why are condensation polymers biodegradeable?
Due to the polar bonds which are susceptible to nucleophilic attack - broken down by hydrolysis slowly
Nucleophiles include water
Why are addition polymers not biodegradeable?
They are chemically inert, due to their molecules being saturated and them having no polar bonds –> unreactive
What is the benefit of using addition polymers in food?
They don’t react due to them being chemically inert
What type of plastics are disposed of using landfill? Give 3 types:
Ones that are:
Too difficult to recycle
Too difficult to separate from other materials
Not enough plastic to extract to make it economically viable
What are the risks of landfill?
Methane released as waste decomposes
Water contamination due to waste leaching
Not very sustainable
Increasingly expensive - land needed
When is incineration used?
When plastics cannot be recycled
What are the risks with incineration?
Could release toxic fumes e.g. burning chlorine based plastics such as PVC as this release HCl gas
What is a benefit to using incineration?
The burning generates energy
How can the risks of incineration be combatted?
Using flue gas scrubbers to neutralise the acidic harmful gases (HCl) –> a base is fired at them
What are 3 ways of disposing of plastics?
Landfill, incineration, recycling
Why is recycling good?
Because most plastics are made from crude oil, crude oil is non-renewable so it reduces the dependency on crude oil.
What are the 2 ways of recycling? Explain:
Cracking and remoulding.
Some plastics e.g. poly(propene) can be remoulded into new objects
Other plastics can be cracked into monomers to be used as organic feedstock for plastics/other substances
4 advantages of recycling plastics?
cheaper than making from scratch
less CO2 than incinerating them
reduces reliance on landfill
preserves non-renewable raw materials e.g. crude oil
4 disadvantages of recycling plastics?
plastics can be contaminated w/ other materials when being recycled
there is a wide variety of different plastics
difficult to remake the original plastic
sorting + processing plastics to be recycled is ££ compared to incinceration
What polymer has hydrogen bonding between the polymer chains?
Kevlar
