polymers

Question 1

describe the main features of addition polymers

Answer 1

monomers-typically alkenes

non-biodegradable due to unreactive non-polar bonds which cannot be hydrolysed

very difficult to convert addition polymer back to its monomers

Question 2

how do you draw a polymer structure and a repeating unit

Answer 2

polymer structure has brackets , repeating unit doesn’t

Question 3

describe the general features of condensation polymers

Answer 3

momomers are difunctional (at opp ends)

biological condensation polymers include proteins

synthetic condensation polymers include polyesters, polyamides

biodegradable as contain polar bonds which attract nucleophiles/acids so therefore can be hydrolysed by enzymes or strong acid/alkali

polyesters typically hydrolysed using alkali, polyamides by acids

Question 4

define monomer

Answer 4

small molecules joined via polymerisation reactions

Question 5

define polymer

Answer 5

long chain molecules made from many smaller molecules (monomers)

Question 6

define addition polymer

Answer 6

long chain saturated polymer made from many unsaturated monomers such as alkenes, no other product formed

Question 7

define condensation polymer

Answer 7

long chain saturated polymer made from amny small saturated monomers with different FGs, small molecules such as waer or HCl released as byproduct

Question 8

give the general reaction used to form polyesters

Answer 8

Question 9

what are the 3 different ways you can make polyamides?

Answer 9

• dicarboxylic acid + diamine
  
  • acid catalyst
  • eqm mixture obtained (yield is <100%)
• diacyl chloride +diamine
  
  • no catalyst as diacyl chloride very reactive
  • complete reaction (higher yield)
  • toxic HCl gases released
• amino acids

Question 10

describe the different ways polymers can be disposed of and the pros/cons of each

Answer 10

• recycling
  
  • physical-melting and remolding existing polymer
  • chemical-cracking into smaller polymer/monomers/new chemicals. this is very expensive however
  • more expensive than landfill/incineration due to cost of sorting, collecting and proccessing
  • product easily contaminated
  • less greenhouse emissions
  • less energy required than to synthesise new polymers = saves on raw material ; cheaper than making new polymers
• landfill
  
  • cheapest/easiest as very kittle equipment required
  • takes up land
  • pollution - polymers take many years to decompose
  • methane released which is a greenhouse gas
• incineration
  
  • used for cities with little land available/hospitals with contaminated waste
  • heat energy released can be used to generate electicity
  • toxic gases released cause acid rain + health problems , greenhouse gases also released
  • expensive due to labour cost, equipment, energy input
  • frees up land
  • less waste sent to landfill

Question 11

why does hydrolysis of this polymer not occur?

Answer 11

the C-C and C-F bonds are too strong