3.12 Polymers Flashcards
Define an addition polymer
a long chain formed from many monomers and no other product is formed
How would you work out the structure of a polymer
Define a condensation polymer
In a condensation reaction, two molecules join to form a larger one, with a small molecule such as H2O or HCl being released
What are the two main types of condensation polymers
Polyesters - formed by carboxylic acids and alcohols
Polyamides - formed by carboxylic acids and amines
Show how a polyester forms
Uses of terylene
carpet and clothing
Show an example of a polyamide being formed
State use and properties of nylon
- used in fibres as clothing
properties : elastic, strong abrasion resistant
Uses of Kevlar and it’s properties
- used in manufacture of body armour and crash helmets
properties : strong, light and heat resistant
Every key fact you need to know about addition polymers
- they are not biodegradable
- they have non polar C-C bonds they cannot be hydrolysed
Every key fact you need to know about condensation polymers
- they are biodegradable as they can be hydrolysed under acidic or basic conditions
- delta positive carbon of the C=O bond can be attacked by nucleophiles
Show an example of hydrolysis of polyesters
Show an example of hydrolysis of polyamides
Describe the intermolecular bonding in condensation polymer chains
There is a permanent dipole between C=O bond and van de waals forces between the chains
Polyamides have hydrogen bonding between C=O bond and the N-H bond in a different chain in addition to the van de waals forces
State use of landfills
useful for disposing plastics that are
- too difficult to recycle
- too difficult to separate from other materials
- not enough plastic to extract to make it economically viable
Problems of landfills
- 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 are needed
- it is becoming expensive to use land for waste disposal and there is a need to reduce our reliance on landfill
Use of incerination
- rubbish is burnt and energy produced is used to generate electricity if it cannot be recyled
- volume of rubbish is greatly reduced
problems of incerination
Some toxins can be released on incineration. Modern incinerators can burn more efficiently and most toxins
and pollutants can be removed. Greenhouse gases will still be emitted though.
purpose of recycling plastics
- most plastics made from crude oil which is a non-renewable source
- recycling means reducing dependency on crude oil for plastics
- plastics can be cracked (polymer chain can be broken up) into monomers to be used as an organic feedstock for plastics
advantages of recycling plastics
advantages :
- cheaper to recycle plastics than make them from scratch
- less carbon dioxide produced
- reduces reliance on landfill
disadvantages of recycling plastics
- plastics can be contaminated with other materials when being recycled
- difficult to recycle plastics due to wide variety of different plastics
- difficult to remake the original plastic from the recycled material
What are the two types of polymerisation you need to know and state the molecules they resemble themself with
addition - alkenes
condensation - diols + dicarboxylic acids or diamines + dicarboxylic acids
