Polymerisation Flashcards
Addition polymers: rules for drawing?
3
- Breaks the C=C bond and extend out
- Square brackets
- ‘n’ in the bottom right corner
What are addition polymers/ how are they formed?
What products?
Alkenes-> polyalkenes- break C=C double bond
Repeated addition reactions
No secondary product
Properties of polyalkenes?
3
Bonding etc?
- Flammable
- Strong C-C and C-H covalent bonds-> not polarised
- Chemically inert/ unreactive
What are condensation polymers?
Products?
Two different molecules
Reaction between two functional groups
Loss of small molecules eg: H2O, CH2OH or HCl
What molecules must be reacted together to form polyamides?
Why
Dicarboxylic acid
Diamine
Need to be ‘di’ so you can keep adding to the chain on both ends
Polyamide properties?
Broken down?
Susceptible to hydrolysis
Therefore can be broken down so are biodegradable
What molecules are reacted together to form polyesters?
Dicarboxylic acid
Diol - di alcohol
Polyester properties?
Broken down?
Hydrolysis
Are biodegradable
What is kevlar?
Polymer of benzene-1,4-diamine and benzene-1,4-dicarboxylic acid
Thermosoftening plastics aka thermoplastics
Properties and purpose?
Soften when heated
Therefore can be moulded
Thermosoftening plastics aka thermoplastics
Chemistry behind properties?
4
Weak intermolecular forces
which break when heated
So chains slide over each other
When it cools the forces reform
Thermosetting polymers
Purpose?
Cannot be remoulded, moulded only once
Thermosetting polymers
Properties? Chemistry behind
Strong covalent linking bonds
Can only decompose when heated very strongly
Big molecules
Advantages to recycling?
- Saves expensive and non-renewable crude oil
- Save energy needed to refine crude oil
Disadvantages to recylcing?
- Need to be collected, transported and sorted
- Uses lots of man-power and is expensive
