Polymers

• Define polymers

  Polymers are very long molecules formed from the linking of a large number of monomers.
• What monomers are used in addition polymerisation?

  Alkenes and substituted alkenes
• What happens in addition polymerisation?

  Many unsaturated monomers joined together - the double bond opens up to form a bond to the next monomer e.g. ethene forms poly(ethene)
• Repeating unit of poly(ethene)

  
• Repeating unit of poly(propene)

  
• Repeating unit of poly(chloroethene)

  
• Uses of poly(ethene)

  Plastic bags and cling film
• Uses of poly(propene)

  Milk crates and ropes
• Uses of poly(chloroethene)/PVC

  Window frames
• Properties of polyalkenes

  - Polymer chains are very long with Van der Waals' forces, which are very strong and have a relatively high melting and boiling point

  Soft - not rigidly held in place by each other
• Define addition polymerisation

  A process in which many alkene monomer molecules react together to give a polymer with no byproducts
• Define condensation polymerisation

  The joining of bifunctional monomers with the elimination of a small molecule such as water or HCl.
• How do you name dicarboxylic acids?

  Name the carbon skeleton first

  Add the word -dioic acid at the end

  No numbers are needed
• Draw benzene-1,4-dicarboxylic acid

  
• How do you name diols?

  Name the carbon skeleton first

  Add the word -diol at the end

  Two numbers are needed to indicate which two carbon atoms the OH groups are attached to
• What do dicarboxylic acids and diols react together to make?

  Esters and water with -OH and -COOH group that can reach out further to make polyesters via condensation reaction
• What does benzene-1,4-dicarboxylic acid and ethane-1,2-diol make via condensation reaction?

  Terylene - used in clothing
• What is a dipeptide?

  2 amino acids joined by a peptide/amide bond in a condensation reaction
• Polypeptide

  A polymer (chain) of many amino acids linked together by peptide bonds.
• Diamines

  Organic compounds characterized by the presence of two amino groups

  
  

  Join two primary amines together
• Naming diamines

  Name the carbon skeleton first

  Add the word diamine at the end

  Two numbers are needed to indicate which two carbon atoms the -NH2 groups are attached to
• What does dicarboxylic acids and diamines form?

  Amide and water that can extend to be polyamide
• What does hexanedioic acid and hexane-1,6-diamine?

  Nylon 6,6 - used to make clothes, ropes and carpets
• What is Kevlar made from?

  Benzene-1,4-diamine and benzene-1,4-dicarboxylic acid
• Properties and uses of Kevlar

  -Very strong

  -Low density

  -Reinforce tyres and aircraft parts

  -Make bulletproof vests
• Properties of polyamides

  Polyamides - Van der Waals' and hydrogen bonding --> making it stronger

  Polyesters have permanent dipole-dipole between the carboxyl bond

  Higher melting point than polyesters
• Define biodegradable

  Substances that can be broken down by microorganisms such as bacteria or fungi
• Biodegradability of addition polymers

  Not biodegradable - polymers persist in the environment

  Unreactive - no polar bonds + strong C-C bonds
• Biodegradability of condensation polymers

  Polyesters - hydrolysed by acids, alkalis and enzymes into dicarboxylic acid and diol, which are biodegradable

  
  

  Polyamides - hydrolysed into diamines and dicarboxylic acid

  
  

  C=O are attacked by nucleophiles -> biodegradable
• Three methods to deal with polymer waste

  -Landfill

  -Incineration

  -Recycling
• Landfills

  Polymer waste is buried in large hole in the ground
• Incineration

  Polymer waste is burned
• Recycling

  Polymer waste is sorted out and re-used
• Disadvantages of landfill

  - Running out of space

  - Expensive for it to be collected and transported

  - Unaesthetic
• Advantages of incineration

  Energy released can be used for heating and generate electricity

  Reduce the need for landfill sites
• Disadvantages of incineration

  Carbon dioxide is made contributing to global warming
• Advantages of recycling

  Reduces emissions of greenhouse gases

  Prevents pollution generated by the use of new materials

  Decreases the amount of materials shipped to landfills

  Preserves natural resources

  Opens up new manufacturing employment opportunities

  Saves energy
• Disadvantages of reccyling

  Expensive as polymers have to collected and sorted out